From 065e8a4d8122d4616b570496915d2c0e2c78cd6b Mon Sep 17 00:00:00 2001 From: Eduardo Julian Date: Thu, 11 Aug 2022 04:15:07 -0400 Subject: Re-named the "case" macro to "when". --- stdlib/source/test/aedifex/artifact/time/date.lux | 2 +- stdlib/source/test/aedifex/cli.lux | 8 +- stdlib/source/test/aedifex/command/auto.lux | 2 +- stdlib/source/test/aedifex/command/build.lux | 10 +- stdlib/source/test/aedifex/command/pom.lux | 4 +- .../source/test/aedifex/dependency/deployment.lux | 2 +- .../source/test/aedifex/dependency/resolution.lux | 8 +- stdlib/source/test/aedifex/dependency/status.lux | 2 +- stdlib/source/test/aedifex/hash.lux | 6 +- stdlib/source/test/aedifex/metadata/artifact.lux | 4 +- stdlib/source/test/aedifex/metadata/snapshot.lux | 4 +- stdlib/source/test/aedifex/package.lux | 10 +- stdlib/source/test/aedifex/parser.lux | 2 +- stdlib/source/test/aedifex/pom.lux | 4 +- stdlib/source/test/aedifex/project.lux | 4 +- stdlib/source/test/aedifex/repository.lux | 4 +- stdlib/source/test/aedifex/repository/local.lux | 2 +- stdlib/source/test/aedifex/repository/remote.lux | 6 +- stdlib/source/test/lux.lux | 60 +- stdlib/source/test/lux/abstract/apply.lux | 2 +- stdlib/source/test/lux/abstract/codec.lux | 2 +- stdlib/source/test/lux/abstract/enum.lux | 2 +- stdlib/source/test/lux/abstract/equivalence.lux | 8 +- stdlib/source/test/lux/abstract/functor.lux | 8 +- stdlib/source/test/lux/abstract/interval.lux | 8 +- stdlib/source/test/lux/abstract/monad/free.lux | 2 +- stdlib/source/test/lux/control/concatenative.lux | 8 - .../source/test/lux/control/concurrency/actor.lux | 12 +- .../source/test/lux/control/concurrency/async.lux | 8 +- stdlib/source/test/lux/control/concurrency/frp.lux | 12 +- .../test/lux/control/concurrency/semaphore.lux | 10 +- stdlib/source/test/lux/control/continuation.lux | 2 +- stdlib/source/test/lux/control/exception.lux | 14 +- .../source/test/lux/control/function/contract.lux | 4 +- stdlib/source/test/lux/control/function/memo.lux | 4 +- stdlib/source/test/lux/control/function/mixin.lux | 10 +- stdlib/source/test/lux/control/function/mutual.lux | 8 +- .../source/test/lux/control/function/predicate.lux | 4 +- stdlib/source/test/lux/control/maybe.lux | 2 +- stdlib/source/test/lux/control/parser.lux | 12 +- stdlib/source/test/lux/control/pipe.lux | 13 +- stdlib/source/test/lux/control/region.lux | 6 +- stdlib/source/test/lux/control/remember.lux | 14 +- stdlib/source/test/lux/control/try.lux | 6 +- stdlib/source/test/lux/data/binary.lux | 24 +- stdlib/source/test/lux/data/collection/array.lux | 20 +- stdlib/source/test/lux/data/collection/bits.lux | 2 +- .../source/test/lux/data/collection/dictionary.lux | 24 +- .../lux/data/collection/dictionary/ordered.lux | 8 +- stdlib/source/test/lux/data/collection/list.lux | 18 +- stdlib/source/test/lux/data/collection/queue.lux | 4 +- .../test/lux/data/collection/queue/priority.lux | 4 +- .../source/test/lux/data/collection/sequence.lux | 6 +- .../test/lux/data/collection/set/ordered.lux | 4 +- stdlib/source/test/lux/data/collection/stack.lux | 6 +- stdlib/source/test/lux/data/collection/tree.lux | 2 +- .../test/lux/data/collection/tree/finger.lux | 6 +- stdlib/source/test/lux/data/format/json.lux | 10 +- stdlib/source/test/lux/data/format/tar.lux | 38 +- stdlib/source/test/lux/data/format/xml.lux | 2 +- stdlib/source/test/lux/data/sum.lux | 8 +- stdlib/source/test/lux/data/text.lux | 20 +- stdlib/source/test/lux/data/text/escape.lux | 10 +- stdlib/source/test/lux/data/text/regex.lux | 12 +- stdlib/source/test/lux/debug.lux | 6 +- stdlib/source/test/lux/documentation.lux | 2 +- stdlib/source/test/lux/ffi.jvm.lux | 26 +- stdlib/source/test/lux/ffi.lua.lux | 2 +- stdlib/source/test/lux/ffi.old.lux | 12 +- stdlib/source/test/lux/math/logic/fuzzy.lux | 4 +- stdlib/source/test/lux/math/modular.lux | 6 +- stdlib/source/test/lux/math/modulus.lux | 6 +- stdlib/source/test/lux/math/number.lux | 6 +- stdlib/source/test/lux/math/number/i64.lux | 4 +- stdlib/source/test/lux/math/number/ratio.lux | 4 +- stdlib/source/test/lux/meta.lux | 10 +- stdlib/source/test/lux/meta/code.lux | 8 +- .../lux/meta/compiler/language/lux/analysis.lux | 62 +- .../compiler/language/lux/analysis/coverage.lux | 26 +- .../compiler/language/lux/analysis/inference.lux | 6 +- .../meta/compiler/language/lux/analysis/macro.lux | 6 +- .../meta/compiler/language/lux/analysis/module.lux | 22 +- .../compiler/language/lux/analysis/pattern.lux | 8 +- .../meta/compiler/language/lux/analysis/scope.lux | 4 +- .../meta/compiler/language/lux/analysis/type.lux | 12 +- .../meta/compiler/language/lux/phase/analysis.lux | 72 +-- .../compiler/language/lux/phase/analysis/case.lux | 637 --------------------- .../language/lux/phase/analysis/complex.lux | 32 +- .../language/lux/phase/analysis/function.lux | 14 +- .../language/lux/phase/analysis/reference.lux | 12 +- .../language/lux/phase/analysis/simple.lux | 10 +- .../compiler/language/lux/phase/analysis/when.lux | 637 +++++++++++++++++++++ .../meta/compiler/language/lux/phase/extension.lux | 10 +- .../language/lux/phase/extension/analysis/lux.lux | 2 +- .../compiler/language/lux/phase/synthesis/case.lux | 360 ------------ .../language/lux/phase/synthesis/function.lux | 22 +- .../compiler/language/lux/phase/synthesis/loop.lux | 8 +- .../language/lux/phase/synthesis/primitive.lux | 4 +- .../language/lux/phase/synthesis/structure.lux | 4 +- .../language/lux/phase/synthesis/variable.lux | 14 +- .../compiler/language/lux/phase/synthesis/when.lux | 360 ++++++++++++ .../test/lux/meta/compiler/language/lux/syntax.lux | 8 +- .../lux/meta/compiler/language/lux/synthesis.lux | 2 +- .../source/test/lux/meta/compiler/meta/archive.lux | 2 +- .../meta/compiler/meta/archive/module/document.lux | 10 +- .../lux/meta/compiler/meta/archive/registry.lux | 12 +- .../source/test/lux/meta/compiler/meta/cache.lux | 2 +- .../test/lux/meta/compiler/meta/cache/artifact.lux | 4 +- .../test/lux/meta/compiler/meta/cache/module.lux | 4 +- .../test/lux/meta/compiler/meta/cache/purge.lux | 2 +- stdlib/source/test/lux/meta/compiler/meta/cli.lux | 6 +- .../source/test/lux/meta/compiler/meta/export.lux | 4 +- stdlib/source/test/lux/meta/compiler/phase.lux | 20 +- stdlib/source/test/lux/meta/compiler/reference.lux | 8 +- .../test/lux/meta/compiler/reference/variable.lux | 2 +- stdlib/source/test/lux/meta/configuration.lux | 4 +- stdlib/source/test/lux/meta/macro.lux | 10 +- stdlib/source/test/lux/meta/macro/local.lux | 2 +- stdlib/source/test/lux/meta/macro/pattern.lux | 18 +- stdlib/source/test/lux/meta/macro/syntax/check.lux | 2 +- .../test/lux/meta/macro/syntax/declaration.lux | 2 +- .../test/lux/meta/macro/syntax/definition.lux | 6 +- .../source/test/lux/meta/macro/syntax/export.lux | 2 +- stdlib/source/test/lux/meta/macro/syntax/input.lux | 2 +- stdlib/source/test/lux/meta/macro/template.lux | 10 +- stdlib/source/test/lux/meta/static.lux | 8 +- stdlib/source/test/lux/meta/target/js.lux | 18 +- stdlib/source/test/lux/meta/target/jvm.lux | 12 +- stdlib/source/test/lux/meta/target/lua.lux | 12 +- stdlib/source/test/lux/meta/target/python.lux | 10 +- stdlib/source/test/lux/meta/target/ruby.lux | 10 +- stdlib/source/test/lux/meta/type.lux | 16 +- stdlib/source/test/lux/meta/type/check.lux | 48 +- stdlib/source/test/lux/meta/type/dynamic.lux | 6 +- stdlib/source/test/lux/meta/type/refinement.lux | 2 +- stdlib/source/test/lux/meta/type/resource.lux | 2 +- stdlib/source/test/lux/meta/version.lux | 2 +- stdlib/source/test/lux/program.lux | 4 +- stdlib/source/test/lux/world/environment.lux | 4 +- stdlib/source/test/lux/world/file.lux | 40 +- stdlib/source/test/lux/world/file/watch.lux | 12 +- stdlib/source/test/lux/world/net/http/client.lux | 4 +- stdlib/source/test/lux/world/shell.lux | 4 +- stdlib/source/test/lux/world/time.lux | 8 +- stdlib/source/test/lux/world/time/date.lux | 4 +- stdlib/source/test/lux/world/time/day.lux | 4 +- stdlib/source/test/lux/world/time/instant.lux | 2 +- stdlib/source/test/lux/world/time/month.lux | 4 +- stdlib/source/test/lux/world/time/year.lux | 6 +- 149 files changed, 1682 insertions(+), 1697 deletions(-) delete mode 100644 stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/case.lux create mode 100644 stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/when.lux delete mode 100644 stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/case.lux create mode 100644 stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/when.lux (limited to 'stdlib/source/test') diff --git a/stdlib/source/test/aedifex/artifact/time/date.lux b/stdlib/source/test/aedifex/artifact/time/date.lux index e50626c79..5efc00d4e 100644 --- a/stdlib/source/test/aedifex/artifact/time/date.lux +++ b/stdlib/source/test/aedifex/artifact/time/date.lux @@ -60,7 +60,7 @@ (try#each (at /.equivalence = expected)) (try.else false))) (_.coverage [/.year_is_out_of_range] - (case (/.date candidate) + (when (/.date candidate) {try.#Success date} (same? candidate (/.value date)) diff --git a/stdlib/source/test/aedifex/cli.lux b/stdlib/source/test/aedifex/cli.lux index a27e90074..b388866c6 100644 --- a/stdlib/source/test/aedifex/cli.lux +++ b/stdlib/source/test/aedifex/cli.lux @@ -53,13 +53,13 @@ (def (compilation_format value) (-> /.Compilation (List Text)) - (case value + (when value {/.#Build} (list "build") {/.#Test} (list "test"))) (def (format value) (-> /.Command (List Text)) - (case value + (when value {/.#Version} (list "version") {/.#Clean} (list "clean") {/.#POM} (list "pom") @@ -77,7 +77,7 @@ (|> expected ..format (cli.result /.command) - (pipe.case + (pipe.when {try.#Success [names actual]} (and (at (list.equivalence text.equivalence) = (list //.default) names) (at /.equivalence = expected actual)) @@ -95,7 +95,7 @@ ..format (list.partial "with" expected_profile) (cli.result /.command) - (pipe.case + (pipe.when {try.#Success [actual_profile actual_command]} (and (at (list.equivalence text.equivalence) = (list expected_profile //.default) actual_profile) (at /.equivalence = expected_command actual_command)) diff --git a/stdlib/source/test/aedifex/command/auto.lux b/stdlib/source/test/aedifex/command/auto.lux index 5dc092327..b202af97f 100644 --- a/stdlib/source/test/aedifex/command/auto.lux +++ b/stdlib/source/test/aedifex/command/auto.lux @@ -110,7 +110,7 @@ fs (shell.async ($build.good_shell [])) resolution) - (at ! each (|>> (pipe.case + (at ! each (|>> (pipe.when {try.#Failure error} (same? end_signal error) diff --git a/stdlib/source/test/aedifex/command/build.lux b/stdlib/source/test/aedifex/command/build.lux index 9aea4828c..c039b6e9c 100644 --- a/stdlib/source/test/aedifex/command/build.lux +++ b/stdlib/source/test/aedifex/command/build.lux @@ -85,7 +85,7 @@ (def (on_read state) (if error? (exception.except shell.no_more_output []) - (case state + (when state {.#Item head tail} {try.#Success [tail head]} @@ -93,7 +93,7 @@ (exception.except shell.no_more_output [])))) (def (on_fail state) (if error? - (case state + (when state {.#Item head tail} {try.#Success [tail head]} @@ -165,7 +165,7 @@ [outcome (/.do! (@version.echo "") (program.async (program.mock environment.empty home working_directory)) fs shell ///dependency/resolution.empty (with_target empty_profile))] (unit.coverage [/.no_specified_program] - (case outcome + (when outcome {try.#Success _} false @@ -174,7 +174,7 @@ (in (do async.monad [outcome (/.do! (@version.echo "") (program.async (program.mock environment.empty home working_directory)) fs shell ///dependency/resolution.empty profile)] (unit.coverage [/.Lux /.no_available_lux] - (case outcome + (when outcome {try.#Success _} false @@ -234,7 +234,7 @@ actual/1 (at console read_line []) actual/2 (at console read_line []) end! (|> (at console read_line []) - (at ! each (|>> (pipe.case + (at ! each (|>> (pipe.when {try.#Failure error} true diff --git a/stdlib/source/test/aedifex/command/pom.lux b/stdlib/source/test/aedifex/command/pom.lux index 32a10f8a3..0d304f19d 100644 --- a/stdlib/source/test/aedifex/command/pom.lux +++ b/stdlib/source/test/aedifex/command/pom.lux @@ -41,7 +41,7 @@ (in (do [! async.monad] [.let [console (@version.echo "")] outcome (/.do! console fs sample)] - (case outcome + (when outcome {try.#Success _} (do ! [verdict (do ///action.monad @@ -64,7 +64,7 @@ {try.#Failure error} (unit.coverage [/.do!] - (case (the ///.#identity sample) + (when (the ///.#identity sample) {.#Some _} false diff --git a/stdlib/source/test/aedifex/dependency/deployment.lux b/stdlib/source/test/aedifex/dependency/deployment.lux index dbc458897..f94ef4421 100644 --- a/stdlib/source/test/aedifex/dependency/deployment.lux +++ b/stdlib/source/test/aedifex/dependency/deployment.lux @@ -69,7 +69,7 @@ (def (request method url headers input) (do io.monad [_ (is (IO Any) - (case [method input] + (when [method input] [{@http.#Put} {.#Some input}] (atom.update! (dictionary.has url input) cache) diff --git a/stdlib/source/test/aedifex/dependency/resolution.lux b/stdlib/source/test/aedifex/dependency/resolution.lux index 6bc81298e..0f353d828 100644 --- a/stdlib/source/test/aedifex/dependency/resolution.lux +++ b/stdlib/source/test/aedifex/dependency/resolution.lux @@ -265,7 +265,7 @@ [///dependency.#artifact expected_artifact ///dependency.#type ///artifact/type.lux_library])] (unit.coverage [/.one] - (case actual_package + (when actual_package {try.#Success actual_package} (at ///package.equivalence = (has ///package.#origin {///repository/origin.#Remote ""} expected_package) @@ -279,7 +279,7 @@ [///dependency.#artifact expected_artifact ///dependency.#type ///artifact/type.lux_library])] (unit.coverage [] - (case actual_package + (when actual_package {try.#Failure error} (exception.match? error) @@ -314,7 +314,7 @@ [///dependency.#artifact expected_artifact ///dependency.#type ///artifact/type.lux_library])] (unit.coverage [/.any] - (case actual_package + (when actual_package {try.#Success actual_package} (at ///package.equivalence = (has ///package.#origin {///repository/origin.#Remote ""} expected_package) @@ -330,7 +330,7 @@ [///dependency.#artifact expected_artifact ///dependency.#type ///artifact/type.lux_library])] (unit.coverage [/.cannot_resolve] - (case actual_package + (when actual_package {try.#Failure error} (exception.match? /.cannot_resolve error) diff --git a/stdlib/source/test/aedifex/dependency/status.lux b/stdlib/source/test/aedifex/dependency/status.lux index b61d35630..85edbdbf8 100644 --- a/stdlib/source/test/aedifex/dependency/status.lux +++ b/stdlib/source/test/aedifex/dependency/status.lux @@ -40,7 +40,7 @@ (do random.monad [payload (binaryT.random 1)] (_.coverage [/.verified] - (case (/.verified payload) + (when (/.verified payload) {/.#Verified sha1 md5} true diff --git a/stdlib/source/test/aedifex/hash.lux b/stdlib/source/test/aedifex/hash.lux index 61cb569fa..7271458b9 100644 --- a/stdlib/source/test/aedifex/hash.lux +++ b/stdlib/source/test/aedifex/hash.lux @@ -50,13 +50,13 @@ [(do random.monad [expected (..random )] (_.coverage [ ] - (and (case ( (/.data expected)) + (and (when ( (/.data expected)) {try.#Success actual} (at /.equivalence = expected actual) {try.#Failure error} false) - (case ( (at binary.monoid composite + (when ( (at binary.monoid composite (/.data expected) (/.data expected))) {try.#Success actual} @@ -81,7 +81,7 @@ [(do random.monad [expected (..random )] (_.coverage [] - (case (at decoded + (when (at decoded (format (at encoded expected) "AABBCC")) {try.#Success actual} diff --git a/stdlib/source/test/aedifex/metadata/artifact.lux b/stdlib/source/test/aedifex/metadata/artifact.lux index f67d1e130..f2d430fb2 100644 --- a/stdlib/source/test/aedifex/metadata/artifact.lux +++ b/stdlib/source/test/aedifex/metadata/artifact.lux @@ -108,10 +108,10 @@ [wrote? (/.write repository artifact expected) actual (/.read repository artifact)] (unit.coverage [/.write /.read] - (and (case wrote? + (and (when wrote? {try.#Success _} true {try.#Failure _} false) - (case actual + (when actual {try.#Success actual} (at /.equivalence = expected actual) diff --git a/stdlib/source/test/aedifex/metadata/snapshot.lux b/stdlib/source/test/aedifex/metadata/snapshot.lux index b41a6ce15..34965c98a 100644 --- a/stdlib/source/test/aedifex/metadata/snapshot.lux +++ b/stdlib/source/test/aedifex/metadata/snapshot.lux @@ -120,10 +120,10 @@ [wrote? (/.write repository artifact expected) actual (/.read repository artifact)] (unit.coverage [/.write /.read] - (and (case wrote? + (and (when wrote? {try.#Success _} true {try.#Failure _} false) - (case actual + (when actual {try.#Success actual} (at /.equivalence = expected actual) diff --git a/stdlib/source/test/aedifex/package.lux b/stdlib/source/test/aedifex/package.lux index 035765b17..dc03b1671 100644 --- a/stdlib/source/test/aedifex/package.lux +++ b/stdlib/source/test/aedifex/package.lux @@ -76,13 +76,13 @@ [actual_pom binary_pom pom_status] (the /.#pom local) [actual_library library_status] (the /.#library local)] - (and (case (the /.#origin local) + (and (when (the /.#origin local) {//origin.#Local ""} true _ false) (let [expected_sha1 (//hash.sha-1 expected_library) expected_md5 (//hash.md5 expected_library)] (and (same? expected_library actual_library) - (case library_status + (when library_status {//status.#Verified actual_sha1 expected_md5} (and (//hash#= expected_sha1 actual_sha1) (//hash#= expected_md5 expected_md5)) @@ -97,7 +97,7 @@ decoded_pom (at xml.codec decoded xml_pom)] (in (at xml.equivalence = actual_pom decoded_pom))) (try.else false)) - (case pom_status + (when pom_status {//status.#Verified actual_sha1 expected_md5} (and (//hash#= expected_sha1 actual_sha1) (//hash#= expected_md5 expected_md5)) @@ -106,7 +106,7 @@ false)))))) (_.coverage [/.dependencies] (let [expected (the //.#dependencies profile)] - (case (/.dependencies package) + (when (/.dependencies package) {try.#Success actual} (at set.equivalence = expected actual) @@ -114,7 +114,7 @@ false))) (_.coverage [/.repositories] (let [expected (the //.#repositories profile)] - (case (/.repositories package) + (when (/.repositories package) {try.#Success actual} (at set.equivalence = expected actual) diff --git a/stdlib/source/test/aedifex/parser.lux b/stdlib/source/test/aedifex/parser.lux index fb2852701..54cdbc17a 100644 --- a/stdlib/source/test/aedifex/parser.lux +++ b/stdlib/source/test/aedifex/parser.lux @@ -84,7 +84,7 @@ //format.project list (.result /.project) - (pipe.case + (pipe.when {try.#Success actual} (|> expected ..with_empty_profile diff --git a/stdlib/source/test/aedifex/pom.lux b/stdlib/source/test/aedifex/pom.lux index c6283f30d..0484599e0 100644 --- a/stdlib/source/test/aedifex/pom.lux +++ b/stdlib/source/test/aedifex/pom.lux @@ -34,11 +34,11 @@ (do random.monad [expected @profile.random] (_.coverage [/.write /.parser] - (case [(/.write expected) + (when [(/.write expected) (the //.#identity expected)] [{try.#Success pom} {.#Some _}] - (case (.result /.parser (list pom)) + (when (.result /.parser (list pom)) {try.#Success actual} (at //.equivalence = (|> (at //.monoid identity) diff --git a/stdlib/source/test/aedifex/project.lux b/stdlib/source/test/aedifex/project.lux index 2db5873e8..29f8b1215 100644 --- a/stdlib/source/test/aedifex/project.lux +++ b/stdlib/source/test/aedifex/project.lux @@ -84,14 +84,14 @@ (try#each (at //.equivalence = (at //.monoid composite sub_profile super_profile))) (try.else false)))) (_.coverage [/.unknown_profile] - (case (/.profile project fake_name) + (when (/.profile project fake_name) {try.#Success _} false {try.#Failure error} (exception.match? /.unknown_profile error))) (_.coverage [/.circular_dependency] - (case (/.profile circular sub_name) + (when (/.profile circular sub_name) {try.#Success _} false diff --git a/stdlib/source/test/aedifex/repository.lux b/stdlib/source/test/aedifex/repository.lux index 72c36f74b..fbb3ef01b 100644 --- a/stdlib/source/test/aedifex/repository.lux +++ b/stdlib/source/test/aedifex/repository.lux @@ -72,9 +72,9 @@ (def the_description "@") (def (on_download uri state) - (case (dictionary.value uri state) + (when (dictionary.value uri state) {.#Some content} - (case (binary.size content) + (when (binary.size content) 0 (exception.except ..not_found [uri]) _ {try.#Success [state content]}) diff --git a/stdlib/source/test/aedifex/repository/local.lux b/stdlib/source/test/aedifex/repository/local.lux index 52a91bea6..96a07f678 100644 --- a/stdlib/source/test/aedifex/repository/local.lux +++ b/stdlib/source/test/aedifex/repository/local.lux @@ -45,7 +45,7 @@ _ (at repo upload uri expected) actual (at repo download uri)] (unit.coverage [/.repository] - (and (case before_upload + (and (when before_upload {try.#Success _} false {try.#Failure _} true) (|> actual diff --git a/stdlib/source/test/aedifex/repository/remote.lux b/stdlib/source/test/aedifex/repository/remote.lux index a5380ddec..5a1c21316 100644 --- a/stdlib/source/test/aedifex/repository/remote.lux +++ b/stdlib/source/test/aedifex/repository/remote.lux @@ -51,7 +51,7 @@ (dictionary.value "User-Agent") (maybe#each (same? /.user_agent)) (maybe.else false)) - (case [method input] + (when [method input] [{@http.#Get} {.#None}] [http/status.ok [@http.#headers (http.headers (list)) @@ -113,7 +113,7 @@ (let [repo (/.repository (..good_http user password) {.#None} address)] - (case (io.run! (at repo upload uri content)) + (when (io.run! (at repo upload uri content)) {try.#Failure error} (exception.match? /.upload_failure error) @@ -123,7 +123,7 @@ (let [repo (/.repository ..bad_http {.#None} address)] - (case (io.run! (at repo download uri)) + (when (io.run! (at repo download uri)) {try.#Failure error} (exception.match? /.download_failure error) diff --git a/stdlib/source/test/lux.lux b/stdlib/source/test/lux.lux index 4d7a695e8..53d699818 100644 --- a/stdlib/source/test/lux.lux +++ b/stdlib/source/test/lux.lux @@ -129,21 +129,21 @@ expected random.nat] (all _.and (_.coverage [/.try] - (case (/.try expected) + (when (/.try expected) {.#Left _} false {.#Right actual} (n.= expected actual))) (_.coverage [/.undefined] - (case (/.try (/.undefined)) + (when (/.try (/.undefined)) {.#Left _} true {.#Right _} false)) (_.coverage [/.panic!] - (case (/.try (/.panic! expected_error)) + (when (/.try (/.panic! expected_error)) {.#Left actual_error} (text.contains? expected_error actual_error) @@ -160,7 +160,7 @@ e/3 random.nat] (all _.and (_.coverage [/.list] - (case (/.list e/0 e/1) + (when (/.list e/0 e/1) (/.list a/0 a/1) (and (n.= e/0 a/0) (n.= e/1 a/1)) @@ -411,7 +411,7 @@ ... (let [scenario (is (-> Any Bit) ... (function (_ _) ... ... TODO: Remove this hack once Jython is no longer being used as the Python interpreter. - ... (`` (for @.python (case (' [']) + ... (`` (for @.python (when (' [']) ... (^.` [ ... ("lux def" (, [_ {.#Symbol ["" _]}]) [] #0) ... (,, (template.spliced ))]) @@ -419,7 +419,7 @@ ... _ ... false) - ... (case (' [']) + ... (when (' [']) ... (^.` [ (,, (template.spliced ))]) ... true @@ -537,7 +537,7 @@ (_.coverage [/.type_of] (same? /.Nat (/.type_of expected))) (_.coverage [/.Primitive] - (case (/.Primitive "foo" [expected/0 expected/1]) + (when (/.Primitive "foo" [expected/0 expected/1]) {.#Primitive "foo" (list actual/0 actual/1)} (and (same? expected/0 actual/0) (same? expected/1 actual/1)) @@ -545,28 +545,28 @@ _ false)) (_.coverage [/.type_literal] - (and (case (/.type_literal [expected/0 expected/1]) + (and (when (/.type_literal [expected/0 expected/1]) {.#Product actual/0 actual/1} (and (same? expected/0 actual/0) (same? expected/1 actual/1)) _ false) - (case (/.type_literal (/.Or expected/0 expected/1)) + (when (/.type_literal (/.Or expected/0 expected/1)) {.#Sum actual/0 actual/1} (and (same? expected/0 actual/0) (same? expected/1 actual/1)) _ false) - (case (/.type_literal (-> expected/0 expected/1)) + (when (/.type_literal (-> expected/0 expected/1)) {.#Function actual/0 actual/1} (and (same? expected/0 actual/0) (same? expected/1 actual/1)) _ false) - (case (/.type_literal (expected/0 expected/1)) + (when (/.type_literal (expected/0 expected/1)) {.#Apply actual/1 actual/0} (and (same? expected/0 actual/0) (same? expected/1 actual/1)) @@ -668,7 +668,7 @@ (in option/1))] (all _.and (_.coverage [/.static] - (case sample + (when sample (/.static option/0) true (/.static option/1) true _ false)) @@ -906,7 +906,7 @@ {.#Some [item/1 {.#Some [item/2 {.#None}]}]}]})] - (case list + (when list {.#Some [actual/0 {.#Some [actual/1 {.#Some [actual/2 {.#None}]}]}]} (and (same? item/0 actual/0) (same? item/1 actual/1) @@ -926,7 +926,7 @@ [[..#left ..#right ]])) -(def for_case +(def for_when Test (do [! random.monad] [expected_nat (at ! each (n.% 1) random.nat) @@ -938,40 +938,40 @@ expected_text (random.either (in "+0.5") (in "+1.25"))] (all _.and - (_.coverage [/.case] - (and (/.case expected_nat + (_.coverage [/.when] + (and (/.when expected_nat 0 true _ false) - (/.case expected_int + (/.when expected_int +0 true _ false) - (/.case expected_rev + (/.when expected_rev .5 true .25 true _ false) - (/.case expected_frac + (/.when expected_frac +0.5 true +1.25 true _ false) - (/.case expected_text + (/.when expected_text "+0.5" true "+1.25" true _ false) - (/.case [expected_nat expected_int] + (/.when [expected_nat expected_int] [0 +0] true _ false) - (/.case [..#left expected_nat ..#right expected_int] + (/.when [..#left expected_nat ..#right expected_int] [..#left 0 ..#right +0] true _ false) - (/.case (is (Either Nat Int) {.#Left expected_nat}) + (/.when (is (Either Nat Int) {.#Left expected_nat}) {.#Left 0} true _ false) - (/.case (is (Either Nat Int) {.#Right expected_int}) + (/.when (is (Either Nat Int) {.#Right expected_int}) {.#Right +0} true _ false) )) ... (_.coverage [/.pattern] - ... (/.case [..#left expected_nat ..#right expected_int] + ... (/.when [..#left expected_nat ..#right expected_int] ... (!pair 0 +0) ... true @@ -1046,7 +1046,7 @@ (set.member? ..possible_targets (the .#target info)) compiling! - (case (the .#mode info) + (when (the .#mode info) {.#Build} true _ false)] {.#Right [lux (list (code.bit (and conforming_target! @@ -1056,7 +1056,7 @@ (syntax (_ []) (do meta.monad [prelude (meta.module .prelude)] - (in (list (code.bit (case (the .#module_state prelude) + (in (list (code.bit (when (the .#module_state prelude) {.#Active} false _ true))))))) @@ -1095,7 +1095,7 @@ let/2 .local let/3 .local]) - (in (list (code.bit (case (the .#scopes lux_state) + (in (list (code.bit (when (the .#scopes lux_state) (list.partial scope/2 _) (let [locals/2 (the .#locals scope/2) expected_locals/2 (set.of_list text.hash (list fn/2 var/2 let/2 @@ -1114,7 +1114,7 @@ local? (is (-> Ref Bit) (function (_ ref) - (case ref + (when ref {.#Local _} true {.#Captured _} false))) captured? (is (-> Ref Bit) @@ -1181,7 +1181,7 @@ ..for_associative ..for_expansion ..for_value - ..for_case + ..for_when ..for_control_flow ..for_def ..for_meta diff --git a/stdlib/source/test/lux/abstract/apply.lux b/stdlib/source/test/lux/abstract/apply.lux index bc48cff4e..8544e5de6 100644 --- a/stdlib/source/test/lux/abstract/apply.lux +++ b/stdlib/source/test/lux/abstract/apply.lux @@ -26,7 +26,7 @@ (all _.and (_.coverage [/.composite] (let [expected (n.+ left right)] - (case (at (/.composite maybe.monad maybe.apply list.apply) on + (when (at (/.composite maybe.monad maybe.apply list.apply) on {.#Some (list right)} {.#Some (list (n.+ left))}) {.#Some (list actual)} diff --git a/stdlib/source/test/lux/abstract/codec.lux b/stdlib/source/test/lux/abstract/codec.lux index c55c7e311..3f07c30cb 100644 --- a/stdlib/source/test/lux/abstract/codec.lux +++ b/stdlib/source/test/lux/abstract/codec.lux @@ -40,7 +40,7 @@ [expected random.bit] (<| (_.covering /._) (_.coverage [/.composite] - (case (|> expected (at ..codec encoded) (at ..codec decoded)) + (when (|> expected (at ..codec encoded) (at ..codec decoded)) {try.#Success actual} (bit#= expected actual) diff --git a/stdlib/source/test/lux/abstract/enum.lux b/stdlib/source/test/lux/abstract/enum.lux index fc50c636a..0f575f3e6 100644 --- a/stdlib/source/test/lux/abstract/enum.lux +++ b/stdlib/source/test/lux/abstract/enum.lux @@ -38,7 +38,7 @@ can_be_backwards? (at (list.equivalence n.equivalence) = (/.range n.enum start end) (list.reversed (/.range n.enum end start))) - every_element_is_a_successor? (case range + every_element_is_a_successor? (when range {.#Item head tail} (|> (list#mix (function (_ next [verdict prev]) [(and verdict diff --git a/stdlib/source/test/lux/abstract/equivalence.lux b/stdlib/source/test/lux/abstract/equivalence.lux index 14d22ae5f..0689009f6 100644 --- a/stdlib/source/test/lux/abstract/equivalence.lux +++ b/stdlib/source/test/lux/abstract/equivalence.lux @@ -29,9 +29,9 @@ (type Variant (.Variant - {#Case0 Bit} - {#Case1 Int} - {#Case2 Frac})) + {#Case_0 Bit} + {#Case_1 Int} + {#Case_2 Frac})) (type Recursive (Rec Recursive @@ -119,7 +119,7 @@ (/.rec (function (_ equivalence) (implementation (def (= left right) - (case [left right] + (when [left right] [{.#End} {.#End}] true diff --git a/stdlib/source/test/lux/abstract/functor.lux b/stdlib/source/test/lux/abstract/functor.lux index c2e5f18eb..b3eee1741 100644 --- a/stdlib/source/test/lux/abstract/functor.lux +++ b/stdlib/source/test/lux/abstract/functor.lux @@ -54,7 +54,7 @@ (<| (_.covering /._) (all _.and (_.coverage [/.Or /.sum] - (and (case (at (/.sum maybe.functor list.functor) each + (and (when (at (/.sum maybe.functor list.functor) each (n.+ shift) {.#Left {.#Some left}}) {.#Left {.#Some actual}} @@ -62,7 +62,7 @@ _ false) - (case (at (/.sum maybe.functor list.functor) each + (when (at (/.sum maybe.functor list.functor) each (n.+ shift) {.#Right (list right)}) {.#Right (list actual)} @@ -71,7 +71,7 @@ _ false))) (_.coverage [/.And /.product] - (case (at (/.product maybe.functor list.functor) each + (when (at (/.product maybe.functor list.functor) each (n.+ shift) [{.#Some left} (list right)]) [{.#Some actualL} (list actualR)] @@ -81,7 +81,7 @@ _ false)) (_.coverage [/.Then /.composite] - (case (at (/.composite maybe.functor list.functor) each + (when (at (/.composite maybe.functor list.functor) each (n.+ shift) {.#Some (list left)}) {.#Some (list actual)} diff --git a/stdlib/source/test/lux/abstract/interval.lux b/stdlib/source/test/lux/abstract/interval.lux index 8270a88b3..9f43008b2 100644 --- a/stdlib/source/test/lux/abstract/interval.lux +++ b/stdlib/source/test/lux/abstract/interval.lux @@ -142,7 +142,7 @@ [[l m r] (|> (random.set n.hash 3 random.nat) (at ! each (|>> set.list (list.sorted n.<) - (pipe.case + (pipe.when (list b t1 t2) [b t1 t2] @@ -165,7 +165,7 @@ [[b t1 t2] (|> (random.set n.hash 3 random.nat) (at ! each (|>> set.list (list.sorted n.<) - (pipe.case + (pipe.when (list b t1 t2) [b t1 t2] @@ -193,7 +193,7 @@ [x0 x1 x2 x3] (|> (random.set n.hash 4 random.nat) (at ! each (|>> set.list (list.sorted n.<) - (pipe.case + (pipe.when (list x0 x1 x2 x3) [x0 x1 x2 x3] @@ -227,7 +227,7 @@ [x0 x1 x2 x3] (|> (random.set n.hash 4 random.nat) (at ! each (|>> set.list (list.sorted n.<) - (pipe.case + (pipe.when (list x0 x1 x2 x3) [x0 x1 x2 x3] diff --git a/stdlib/source/test/lux/abstract/monad/free.lux b/stdlib/source/test/lux/abstract/monad/free.lux index 7a4375c27..eb67429b2 100644 --- a/stdlib/source/test/lux/abstract/monad/free.lux +++ b/stdlib/source/test/lux/abstract/monad/free.lux @@ -25,7 +25,7 @@ (def (interpret free) (All (_ a) (-> (/.Free List a) (List a))) - (case free + (when free {/.#Pure value} (list value) diff --git a/stdlib/source/test/lux/control/concatenative.lux b/stdlib/source/test/lux/control/concatenative.lux index aec54bebe..b49761269 100644 --- a/stdlib/source/test/lux/control/concatenative.lux +++ b/stdlib/source/test/lux/control/concatenative.lux @@ -280,14 +280,6 @@ (/.push (/.apply_2 n.+)) /.partial /.call)))) - (_.coverage [/.when] - (n.= (if choice - (++ sample) - sample) - (/.value (|>> (/.push sample) - (/.push choice) - (/.push (/.apply_1 ++)) - /.when)))) (_.coverage [/.?] (n.= (if choice (++ sample) diff --git a/stdlib/source/test/lux/control/concurrency/actor.lux b/stdlib/source/test/lux/control/concurrency/actor.lux index 35fbb8027..d11016a4b 100644 --- a/stdlib/source/test/lux/control/concurrency/actor.lux +++ b/stdlib/source/test/lux/control/concurrency/actor.lux @@ -42,7 +42,7 @@ (def (mailed? outcome) (-> (Try Any) Bit) - (case outcome + (when outcome {try.#Success _} true {try.#Failure _} false)) @@ -91,7 +91,7 @@ (function (_ message state self) (do [! async.monad] [outcome (message state self)] - (case outcome + (when outcome {try.#Failure cause} (do ! [_ (async.future (write cause))] @@ -104,7 +104,7 @@ _ (async.delay 100) result (async.future (async.value read))] (unit.coverage [/.poisoned] - (case result + (when result {.#Some error} (exception.match? /.poisoned error) @@ -126,7 +126,7 @@ _ (/.poison! counter)] (/.mail! ++! counter)))] (unit.coverage [/.dead] - (case result + (when result {try.#Success outcome} false @@ -144,7 +144,7 @@ obituary (/.obituary' actor)] (in {try.#Success [actor sent? alive? obituary]})))] (unit.coverage [/.Obituary /.obituary'] - (case result + (when result {try.#Success [actor sent? alive? {.#Some [error state (list single_pending_message)]}]} (and (..mailed? sent?) (not alive?) @@ -165,7 +165,7 @@ (n.= 2 output_2) (n.= 3 output_3))))] (unit.coverage [/.Message /.tell!] - (case result + (when result {try.#Success outcome} outcome diff --git a/stdlib/source/test/lux/control/concurrency/async.lux b/stdlib/source/test/lux/control/concurrency/async.lux index 5ca8704ff..36aba9dfd 100644 --- a/stdlib/source/test/lux/control/concurrency/async.lux +++ b/stdlib/source/test/lux/control/concurrency/async.lux @@ -40,7 +40,7 @@ (do io.monad [?left (/.value left) ?right (/.value right)] - (in (case [?left ?right] + (in (when [?left ?right] [{.#Some left} {.#Some right}] (== left right) @@ -121,7 +121,7 @@ ?right (/.or (/.after waiting_time dummy) (in rightE))] (unit.coverage [/.or] - (case [?left ?right] + (when [?left ?right] [{.#Left leftA} {.#Right rightA}] (n.= (n.+ leftE rightE) (n.+ leftA rightA)) @@ -142,7 +142,7 @@ (/.async []))] ?never (/.future (/.value async))] (unit.coverage [/.value] - (case [?actual ?never] + (when [?actual ?never] [{.#Some actual} {.#None}] (n.= expected actual) @@ -160,7 +160,7 @@ [?none (/.within 0 (/.after waiting_time dummy)) ?actual (/.within waiting_time (in expected))] (unit.coverage [/.within] - (case [?none ?actual] + (when [?none ?actual] [{.#None} {.#Some actual}] (n.= expected actual) diff --git a/stdlib/source/test/lux/control/concurrency/frp.lux b/stdlib/source/test/lux/control/concurrency/frp.lux index a3fe7263c..16cae30d8 100644 --- a/stdlib/source/test/lux/control/concurrency/frp.lux +++ b/stdlib/source/test/lux/control/concurrency/frp.lux @@ -40,7 +40,7 @@ (do io.monad [?left (async.value left) ?right (async.value right)] - (in (case [?left ?right] + (in (when [?left ?right] [{.#Some {.#Some [left _]}} {.#Some {.#Some [right _]}}] (== left right) @@ -50,13 +50,13 @@ (def (take_amount amount_of_polls [channel sink]) (All (_ a) (-> Nat [(/.Channel a) (/.Sink a)] (Async (List a)))) - (case amount_of_polls + (when amount_of_polls 0 (do async.monad [_ (async.future (at sink close))] (in {.#End})) _ (do [! async.monad] [event channel] - (case event + (when event {.#None} (in {.#End}) @@ -86,7 +86,7 @@ ($monad.spec ..injection ..comparison /.monad)) (_.coverage [/.Channel /.Sink /.channel] - (case (io.run! + (when (io.run! (do (try.with io.monad) [.let [[channel sink] (is [(/.Channel Nat) (/.Sink Nat)] (/.channel []))] @@ -97,7 +97,7 @@ (io.run! (do io.monad [?actual (async.value channel)] - (in (case ?actual + (in (when ?actual {.#Some {.#Some [actual _]}} (n.= sample actual) @@ -107,7 +107,7 @@ {try.#Failure error} false)) (_.coverage [/.already_closed] - (case (io.run! + (when (io.run! (do (try.with io.monad) [.let [[channel sink] (is [(/.Channel Nat) (/.Sink Nat)] (/.channel []))] diff --git a/stdlib/source/test/lux/control/concurrency/semaphore.lux b/stdlib/source/test/lux/control/concurrency/semaphore.lux index 19a99f55d..54143c345 100644 --- a/stdlib/source/test/lux/control/concurrency/semaphore.lux +++ b/stdlib/source/test/lux/control/concurrency/semaphore.lux @@ -46,7 +46,7 @@ (in (do async.monad [result (async.within ..delay (/.wait! semaphore))] (unit.coverage [/.semaphore] - (case result + (when result {.#Some _} true @@ -59,7 +59,7 @@ [_ (monad.each ! /.wait! (list.repeated initial_open_positions semaphore)) result (async.within ..delay (/.wait! semaphore))] (unit.coverage [/.wait!] - (case result + (when result {.#Some _} false @@ -75,7 +75,7 @@ open_positions (/.signal! semaphore) result/1 (async.within ..delay block)] (unit.coverage [/.signal!] - (case [result/0 result/1 open_positions] + (when [result/0 result/1 open_positions] [{.#None} {.#Some _} {try.#Success +0}] true @@ -87,7 +87,7 @@ (in (do async.monad [outcome (/.signal! semaphore)] (unit.coverage [/.semaphore_is_maxed_out] - (case outcome + (when outcome {try.#Failure error} (exception.match? /.semaphore_is_maxed_out error) @@ -146,7 +146,7 @@ (do random.monad [raw random.nat] (_.coverage [/.Limit /.limit] - (case [raw (/.limit raw)] + (when [raw (/.limit raw)] [0 {.#None}] true diff --git a/stdlib/source/test/lux/control/continuation.lux b/stdlib/source/test/lux/control/continuation.lux index 8f57a99dc..ce7b9d985 100644 --- a/stdlib/source/test/lux/control/continuation.lux +++ b/stdlib/source/test/lux/control/continuation.lux @@ -72,7 +72,7 @@ visit (is (-> (List Nat) (/.Cont (List Nat) (List Nat))) (function (visit xs) - (case xs + (when xs {.#End} (_#in {.#End}) diff --git a/stdlib/source/test/lux/control/exception.lux b/stdlib/source/test/lux/control/exception.lux index 1021d8522..d90494bd9 100644 --- a/stdlib/source/test/lux/control/exception.lux +++ b/stdlib/source/test/lux/control/exception.lux @@ -39,11 +39,11 @@ (_.for [/.Exception]) (all _.and (_.coverage [/.except] - (case (/.except ..an_exception []) + (when (/.except ..an_exception []) {try.#Success _} false {try.#Failure _} true)) (_.coverage [/.error] - (case (/.except ..an_exception []) + (when (/.except ..an_exception []) {try.#Success _} false @@ -53,7 +53,7 @@ (/.match? ..an_exception (/.error ..an_exception []))) (_.coverage [/.assertion] - (case (/.assertion ..an_exception [] assertion_succeeded?) + (when (/.assertion ..an_exception [] assertion_succeeded?) {try.#Success _} assertion_succeeded? @@ -89,13 +89,13 @@ (text.contains? field1 enumeration) (text.contains? value1 enumeration)))) (_.coverage [/.with] - (and (case (/.with ..an_exception [] {try.#Success expected}) + (and (when (/.with ..an_exception [] {try.#Success expected}) {try.#Success actual} (n.= expected actual) {try.#Failure _} false) - (case (/.with ..an_exception [] {try.#Failure ""}) + (when (/.with ..an_exception [] {try.#Failure ""}) {try.#Success _} false {try.#Failure message} (text#= message (/.error ..an_exception []))) - (case (/.with ..an_exception [] + (when (/.with ..an_exception [] (is (Try Nat) (/.except ..another_exception []))) {try.#Success _} @@ -105,7 +105,7 @@ (and (text.contains? (/.error ..an_exception []) message) (text.contains? (/.error ..another_exception []) message))))) (_.coverage [/.exception] - (case (/.except ..custom_exception [expected]) + (when (/.except ..custom_exception [expected]) {try.#Success _} false diff --git a/stdlib/source/test/lux/control/function/contract.lux b/stdlib/source/test/lux/control/function/contract.lux index 312e7070f..44666a08d 100644 --- a/stdlib/source/test/lux/control/function/contract.lux +++ b/stdlib/source/test/lux/control/function/contract.lux @@ -24,7 +24,7 @@ [expected random.nat]) (all _.and (_.coverage [/.pre /.pre_condition_failed] - (case (try (/.pre (n.even? expected) + (when (try (/.pre (n.even? expected) true)) {try.#Success output} output @@ -34,7 +34,7 @@ error) (not (n.even? expected))))) (_.coverage [/.post /.post_condition_failed] - (case (try (/.post n.odd? + (when (try (/.post n.odd? expected)) {try.#Success actual} (same? expected actual) diff --git a/stdlib/source/test/lux/control/function/memo.lux b/stdlib/source/test/lux/control/function/memo.lux index d1ab63220..8c024ff60 100644 --- a/stdlib/source/test/lux/control/function/memo.lux +++ b/stdlib/source/test/lux/control/function/memo.lux @@ -32,7 +32,7 @@ (def (fibonacci again input) (/.Memo Nat Nat) - (case input + (when input 0 (state#in 0) 1 (state#in 1) _ (do state.monad @@ -110,7 +110,7 @@ (//.mixed /.memoization) (is (//.Mixin Nat (State (Dictionary Nat Nat) Nat)) (function (factorial delegate again input) - (case input + (when input (^.or 0 1) (at state.monad in 1) _ (do state.monad [output' (again (-- input))] diff --git a/stdlib/source/test/lux/control/function/mixin.lux b/stdlib/source/test/lux/control/function/mixin.lux index 9fce7f116..9d403e17d 100644 --- a/stdlib/source/test/lux/control/function/mixin.lux +++ b/stdlib/source/test/lux/control/function/mixin.lux @@ -55,7 +55,7 @@ (_.coverage [/.fixed] (let [factorial (/.fixed (function (_ delegate again input) - (case input + (when input (^.or 0 1) 1 _ (n.* input (again (-- input))))))] (n.= expected @@ -63,7 +63,7 @@ (_.coverage [/.mixed] (let [bottom (is (/.Mixin Nat Nat) (function (_ delegate again input) - (case input + (when input (^.or 0 1) 1 _ (delegate input)))) multiplication (is (/.Mixin Nat Nat) @@ -75,7 +75,7 @@ (_.coverage [/.nothing] (let [loop (is (/.Mixin Nat Nat) (function (_ delegate again input) - (case input + (when input (^.or 0 1) 1 _ (n.* input (delegate (-- input)))))) left (/.fixed (/.mixed /.nothing loop)) @@ -90,7 +90,7 @@ 1)) bottom? (is (Predicate Nat) (function (_ input) - (case input + (when input (^.or 0 1) true _ false))) multiplication (is (/.Mixin Nat Nat) @@ -132,7 +132,7 @@ (let [factorial (/.fixed (/.of_recursive (function (_ again input) - (case input + (when input (^.or 0 1) 1 _ (n.* input (again (-- input)))))))] (n.= expected diff --git a/stdlib/source/test/lux/control/function/mutual.lux b/stdlib/source/test/lux/control/function/mutual.lux index a4bfed417..8f6a7069d 100644 --- a/stdlib/source/test/lux/control/function/mutual.lux +++ b/stdlib/source/test/lux/control/function/mutual.lux @@ -24,13 +24,13 @@ (<| (_.coverage [/.let]) (/.let [(even? number) (-> Nat Bit) - (case number + (when number 0 true _ (odd? (-- number))) (odd? number) (-> Nat Bit) - (case number + (when number 0 false _ (even? (-- number)))] (and (bit#= expected (even? sample)) @@ -39,13 +39,13 @@ (/.def [(even? number) (-> Nat Bit) - (case number + (when number 0 true _ (odd? (-- number)))] [(odd? number) (-> Nat Bit) - (case number + (when number 0 false _ (even? (-- number)))]) diff --git a/stdlib/source/test/lux/control/function/predicate.lux b/stdlib/source/test/lux/control/function/predicate.lux index 6855a1b2d..9a016094c 100644 --- a/stdlib/source/test/lux/control/function/predicate.lux +++ b/stdlib/source/test/lux/control/function/predicate.lux @@ -25,7 +25,7 @@ (def (multiple? factor) (-> Nat (/.Predicate Nat)) - (case factor + (when factor 0 (function.constant false) _ (|>> (n.% factor) (n.= 0)))) @@ -80,7 +80,7 @@ any_even? (is (/.Predicate (List Nat)) (/.rec (function (_ again) (function (_ values) - (case values + (when values {.#End} false diff --git a/stdlib/source/test/lux/control/maybe.lux b/stdlib/source/test/lux/control/maybe.lux index e4efb58b0..d99622737 100644 --- a/stdlib/source/test/lux/control/maybe.lux +++ b/stdlib/source/test/lux/control/maybe.lux @@ -56,7 +56,7 @@ [a (lifted (io#in left)) b (in right)] (in (n.+ a b)))) - (pipe.case + (pipe.when {.#Some actual} (n.= expected actual) diff --git a/stdlib/source/test/lux/control/parser.lux b/stdlib/source/test/lux/control/parser.lux index 9922a79dc..10e897f03 100644 --- a/stdlib/source/test/lux/control/parser.lux +++ b/stdlib/source/test/lux/control/parser.lux @@ -31,7 +31,7 @@ (def (should_fail expected input) (All (_ a) (-> Text (Try a) Bit)) - (case input + (when input {try.#Failure actual} (text#= expected actual) @@ -40,7 +40,7 @@ (def (enforced? parser input) (All (_ s) (-> (Parser s Any) s Bit)) - (case (/.result parser input) + (when (/.result parser input) {try.#Success [_ []]} true @@ -49,7 +49,7 @@ (def (found? parser input) (All (_ s) (-> (Parser s Bit) s Bit)) - (case (/.result parser input) + (when (/.result parser input) {try.#Success [_ .true]} true @@ -58,7 +58,7 @@ (def (fails? input) (All (_ a) (-> (Try a) Bit)) - (case input + (when input {try.#Failure _} true @@ -69,7 +69,7 @@ (syntax (_ [pattern .any then .any input .any]) - (in (list (` (case (, input) + (in (list (` (when (, input) {try.#Success [(,' _) (, pattern)]} (, then) @@ -327,7 +327,7 @@ (def comparison (Comparison (All (_ a i) (Parser i a))) (function (_ == left right) - (case [(/.result left []) (/.result right [])] + (when [(/.result left []) (/.result right [])] [{try.#Success [_ left]} {try.#Success [_ right]}] (== left right) diff --git a/stdlib/source/test/lux/control/pipe.lux b/stdlib/source/test/lux/control/pipe.lux index 50d5bb67f..5f367ab9b 100644 --- a/stdlib/source/test/lux/control/pipe.lux +++ b/stdlib/source/test/lux/control/pipe.lux @@ -51,13 +51,6 @@ (/.if [n.even?] [(/.new "even" [])] [(/.new "odd" [])])))) - (_.coverage [/.when] - (n.= (if (n.even? sample) - (n.* 2 sample) - sample) - (|> sample - (/.when [n.even?] - [(n.* 2)])))) (_.coverage [/.while] (n.= (n.* 10 sample) (|> sample @@ -83,8 +76,8 @@ (and (n.= (++ sample) left) (n.= (-- sample) middle) (text#= (%.nat sample) right)))) - (_.coverage [/.case] - (text#= (case (n.% 10 sample) + (_.coverage [/.when] + (text#= (when (n.% 10 sample) 0 "zero" 1 "one" 2 "two" @@ -98,7 +91,7 @@ _ "???") (|> sample (n.% 10) - (/.case + (/.when 0 "zero" 1 "one" 2 "two" diff --git a/stdlib/source/test/lux/control/region.lux b/stdlib/source/test/lux/control/region.lux index b409a7d24..54e22f811 100644 --- a/stdlib/source/test/lux/control/region.lux +++ b/stdlib/source/test/lux/control/region.lux @@ -34,7 +34,7 @@ (def (success? result) (All (_ a) (-> (Try a) Bit)) - (case result + (when result {try.#Success _} true @@ -43,7 +43,7 @@ (def (throws? exception result) (All (_ e a) (-> (Exception e) (Try a) Bit)) - (case result + (when result {try.#Success _} false @@ -60,7 +60,7 @@ (def comparison (Comparison (All (_ a) (All (_ ! r) (Region r (Thread !) a)))) (function (_ == left right) - (case [(sharing [a] + (when [(sharing [a] (is (Equivalence a) ==) (is (Try a) diff --git a/stdlib/source/test/lux/control/remember.lux b/stdlib/source/test/lux/control/remember.lux index 9e75c00e6..963b3fbc1 100644 --- a/stdlib/source/test/lux/control/remember.lux +++ b/stdlib/source/test/lux/control/remember.lux @@ -39,14 +39,14 @@ (` ((, (code.symbol macro)) (, (code.text (%.date deadline))) (, (code.text message)) - (,* (case focus + (,* (when focus {.#None} (list) {.#Some focus} (list focus)))))) (def (attempt computation) (All (_ a) (-> (Meta a) (Meta (Try a)))) (function (_ compiler) - (case (computation compiler) + (when (computation compiler) {try.#Success [compiler output]} {try.#Success [compiler {try.#Success output}]} @@ -57,7 +57,7 @@ (-> Date Text (Maybe Code) Text Bit) (and (text.contains? (%.date deadline) failure) (text.contains? message failure) - (case focus + (when focus {.#None} true @@ -80,27 +80,27 @@ should_fail1 (..attempt (expansion.complete (..memory macro yesterday message {.#Some expected}))) should_succeed0 (..attempt (expansion.complete (..memory macro tomorrow message {.#None}))) should_succeed1 (..attempt (expansion.complete (..memory macro tomorrow message {.#Some expected})))] - (in (list (code.bit (and (case should_fail0 + (in (list (code.bit (and (when should_fail0 {try.#Failure error} (and (test_failure yesterday message {.#None} error) (text.contains? extra error)) _ false) - (case should_fail1 + (when should_fail1 {try.#Failure error} (and (test_failure yesterday message {.#Some expected} error) (text.contains? extra error)) _ false) - (case should_succeed0 + (when should_succeed0 {try.#Success (list)} true _ false) - (case should_succeed1 + (when should_succeed1 {try.#Success (list actual)} (same? expected actual) diff --git a/stdlib/source/test/lux/control/try.lux b/stdlib/source/test/lux/control/try.lux index 857d67ac5..00aac612f 100644 --- a/stdlib/source/test/lux/control/try.lux +++ b/stdlib/source/test/lux/control/try.lux @@ -60,7 +60,7 @@ (n.= expected (/.trusted {/.#Success expected}))) (_.coverage [/.of_maybe] - (case [(/.of_maybe {.#Some expected}) + (when [(/.of_maybe {.#Some expected}) (/.of_maybe {.#None})] [{/.#Success actual} {/.#Failure _}] (n.= expected actual) @@ -68,7 +68,7 @@ _ false)) (_.coverage [/.maybe] - (case [(/.maybe {/.#Success expected}) + (when [(/.maybe {/.#Success expected}) (/.maybe (is (/.Try Nat) {/.#Failure error}))] [{.#Some actual} {.#None}] (n.= expected actual) @@ -87,7 +87,7 @@ b (in alternative)] (in (n.+ a b))) io.run! - (pipe.case + (pipe.when {/.#Success result} (n.= (n.+ expected alternative) result) diff --git a/stdlib/source/test/lux/data/binary.lux b/stdlib/source/test/lux/data/binary.lux index 296867c13..05c3c2c6a 100644 --- a/stdlib/source/test/lux/data/binary.lux +++ b/stdlib/source/test/lux/data/binary.lux @@ -54,7 +54,7 @@ (def !expect (template (_ ) - [(case + [(when true @@ -68,7 +68,7 @@ (|> value (at utf8.codec encoded) (at utf8.codec decoded) - (pipe.case + (pipe.when {try.#Success converted} (text#= value converted) @@ -423,7 +423,7 @@ (def (succeed result) (-> (Try Bit) Bit) - (case result + (when result {try.#Failure _} false @@ -443,7 +443,7 @@ (def (throws? exception try) (All (_ e a) (-> (Exception e) (Try a) Bit)) - (case try + (when try {try.#Failure error} (exception.match? exception error) @@ -454,7 +454,7 @@ (-> Nat (-> Nat /.Binary (Try Nat)) (-> Nat Nat /.Binary (Try Any)) Nat Bit) (let [bytes (i64.left_shifted power 1) binary (/.empty bytes) - cap (case bytes + cap (when bytes 8 (-- 0) _ (|> 1 (i64.left_shifted (n.* 8 bytes)) --)) capped_value (i64.and cap value)] @@ -499,7 +499,7 @@ [(_.coverage [ ] (let [bytes (i64.left_shifted 1) binary (!.empty bytes) - cap (case bytes + cap (when bytes 8 (-- 0) _ (|> 1 (i64.left_shifted (n.* 8 bytes)) --)) capped_value (i64.and cap value) @@ -517,7 +517,7 @@ (_.coverage [!.slice] (let [random_slice (!.slice offset length sample) idxs (is (List Nat) - (case length + (when length 0 (list) _ (enum.range n.enum 0 (-- length)))) reader (function (_ binary idx) @@ -578,13 +578,13 @@ (_.coverage [/.slice] (let [random_slice (try.trusted (/.slice offset length sample)) idxs (is (List Nat) - (case length + (when length 0 (list) _ (enum.range n.enum 0 (-- length)))) reader (function (_ binary idx) (/.bits_8 idx binary))] (and (n.= length (/.size random_slice)) - (case [(monad.each try.monad (|>> (n.+ offset) (reader sample)) idxs) + (when [(monad.each try.monad (|>> (n.+ offset) (reader sample)) idxs) (monad.each try.monad (reader random_slice) idxs)] [{try.#Success binary_vals} {try.#Success slice_vals}] (at (list.equivalence n.equivalence) = binary_vals slice_vals) @@ -594,14 +594,14 @@ (_.coverage [/.slice_out_of_bounds] (and (throws? /.slice_out_of_bounds (/.slice size size sample)) (let [verdict (throws? /.slice_out_of_bounds (/.slice offset size sample))] - (case offset + (when offset 0 (not verdict) _ verdict)))) (_.coverage [/.after] (and (at /.equivalence = sample (/.after 0 sample)) (at /.equivalence = (/.empty 0) (/.after size sample)) (n.= (n.- offset size) (/.size (/.after offset sample))) - (case (list.reversed (..as_list sample)) + (when (list.reversed (..as_list sample)) {.#End} false @@ -609,7 +609,7 @@ (n.= (list.mix n.+ 0 tail) (/.mix n.+ 0 (/.after 1 sample)))))) (_.coverage [/.copy!] - (and (case (/.copy! size 0 sample 0 (/.empty size)) + (and (when (/.copy! size 0 sample 0 (/.empty size)) {try.#Success output} (and (not (same? sample output)) (at /.equivalence = sample output)) diff --git a/stdlib/source/test/lux/data/collection/array.lux b/stdlib/source/test/lux/data/collection/array.lux index f12014f24..b13c77f6b 100644 --- a/stdlib/source/test/lux/data/collection/array.lux +++ b/stdlib/source/test/lux/data/collection/array.lux @@ -70,7 +70,7 @@ {.#Some (at n.decimal encoded value)} {.#None})))] (_.coverage [/.one] - (case [(|> evens + (when [(|> evens (/#each (at n.decimal encoded)) (/.item 0)) (/.one choose evens)] @@ -87,12 +87,12 @@ (/.example n.even? the_array) (list.example n.even? (/.list {.#None} the_array)))) (_.coverage [/.example'] - (case [(/.example n.even? the_array) + (when [(/.example n.even? the_array) (/.example' (function (_ idx member) (n.even? member)) the_array)] [{.#Some expected} {.#Some [idx actual]}] - (case (/.item idx the_array) + (when (/.item idx the_array) {.#Some again} (and (n.= expected actual) (n.= actual again)) @@ -156,7 +156,7 @@ (n.= size (!.size (is (Array Nat) (!.empty size))))) (_.coverage [!.primitive] - (case !.Array + (when !.Array (<| {.#Named (symbol !.Array)} {.#UnivQ (list)} {.#Primitive nominal_type (list {.#Parameter 1})}) @@ -281,7 +281,7 @@ (!.example n.even? the_array) (list.example n.even? (!.list {.#None} the_array)))) (_.coverage [!.example'] - (case [(!.example n.even? the_array) + (when [(!.example n.even? the_array) (!.example' (function (_ idx member) (n.even? member)) the_array)] @@ -324,7 +324,7 @@ (n.= size (/.size (is (Array Nat) (/.empty size))))) (_.coverage [/.primitive] - (case /.Array + (when /.Array (<| {.#Named (symbol /.Array)} {.#Named (symbol !.Array)} {.#UnivQ (list)} @@ -337,7 +337,7 @@ (let [the_array (|> (/.empty 2) (is (Array Nat)) (/.has! 0 expected))] - (case [(/.item 0 the_array) + (when [(/.item 0 the_array) (/.item 1 the_array)] [{.#Some actual} {.#None}] (n.= expected actual) @@ -348,7 +348,7 @@ (let [the_array (|> (/.empty 1) (is (Array Nat)) (/.has! 0 expected))] - (case [(/.item 0 the_array) + (when [(/.item 0 the_array) (/.item 0 (/.lacks! 0 the_array))] [{.#Some actual} {.#None}] (n.= expected actual) @@ -372,7 +372,7 @@ (is (Array Nat)) (/.has! 0 base) (/.revised! 0 (n.+ shift)))] - (case (/.item 0 the_array) + (when (/.item 0 the_array) {.#Some actual} (n.= expected actual) @@ -384,7 +384,7 @@ (/.has! 0 base) (/.upsert! 0 dummy (n.+ shift)) (/.upsert! 1 base (n.+ shift)))] - (case [(/.item 0 the_array) + (when [(/.item 0 the_array) (/.item 1 the_array)] [{.#Some actual/0} {.#Some actual/1}] (and (n.= expected actual/0) diff --git a/stdlib/source/test/lux/data/collection/bits.lux b/stdlib/source/test/lux/data/collection/bits.lux index 379cfd131..2a134ab17 100644 --- a/stdlib/source/test/lux/data/collection/bits.lux +++ b/stdlib/source/test/lux/data/collection/bits.lux @@ -26,7 +26,7 @@ (Random Bits) (do [! random.monad] [size (at ! each (n.% 1,000) random.nat)] - (case size + (when size 0 (in /.empty) _ (do [! random.monad] [idx (|> random.nat (at ! each (n.% size)))] diff --git a/stdlib/source/test/lux/data/collection/dictionary.lux b/stdlib/source/test/lux/data/collection/dictionary.lux index 369bddd2d..d02d9f3a4 100644 --- a/stdlib/source/test/lux/data/collection/dictionary.lux +++ b/stdlib/source/test/lux/data/collection/dictionary.lux @@ -44,7 +44,7 @@ (n.= size (/.size dict))) (_.coverage [/.empty?] - (case size + (when size 0 (/.empty? dict) _ (not (/.empty? dict)))) @@ -147,26 +147,26 @@ (/.keys dict))) (_.coverage [/.value] - (and (list.every? (function (_ key) (case (/.value key dict) + (and (list.every? (function (_ key) (when (/.value key dict) {.#Some _} true _ false)) (/.keys dict)) - (case (/.value non_key dict) + (when (/.value non_key dict) {.#Some _} false _ true))) (_.coverage [/.has] (and (n.= (++ (/.size dict)) (/.size (/.has non_key test_val dict))) - (case (/.value non_key (/.has non_key test_val dict)) + (when (/.value non_key (/.has non_key test_val dict)) {.#Some v} (n.= test_val v) _ true))) (_.coverage [/.has' /.key_already_exists] (let [can_put_new_keys! - (case (/.has' non_key test_val dict) + (when (/.has' non_key test_val dict) {try.#Success dict} - (case (/.value non_key dict) + (when (/.value non_key dict) {.#Some v} (n.= test_val v) _ true) @@ -176,7 +176,7 @@ cannot_put_old_keys! (or (n.= 0 size) (let [first_key (|> dict /.keys list.head maybe.trusted)] - (case (/.has' first_key test_val dict) + (when (/.has' first_key test_val dict) {try.#Success _} false @@ -189,7 +189,7 @@ (and (let [base (/.has non_key test_val dict)] (and (/.key? base non_key) (not (/.key? (/.lacks non_key base) non_key)))) - (case (list.head (/.keys dict)) + (when (list.head (/.keys dict)) {.#None} true @@ -200,7 +200,7 @@ (_.coverage [/.revised] (let [base (/.has non_key test_val dict) updt (/.revised non_key ++ base)] - (case [(/.value non_key base) (/.value non_key updt)] + (when [(/.value non_key base) (/.value non_key updt)] [{.#Some x} {.#Some y}] (n.= (++ x) y) @@ -209,7 +209,7 @@ (_.coverage [/.revised'] (let [can_upsert_new_key! - (case (/.value non_key (/.revised' non_key test_val ++ dict)) + (when (/.value non_key (/.revised' non_key test_val ++ dict)) {.#Some inserted} (n.= (++ test_val) inserted) @@ -217,12 +217,12 @@ false) can_upsert_old_key! - (case (list.head (/.entries dict)) + (when (list.head (/.entries dict)) {.#None} true {.#Some [known_key known_value]} - (case (/.value known_key (/.revised' known_key test_val ++ dict)) + (when (/.value known_key (/.revised' known_key test_val ++ dict)) {.#Some updated} (n.= (++ known_value) updated) diff --git a/stdlib/source/test/lux/data/collection/dictionary/ordered.lux b/stdlib/source/test/lux/data/collection/dictionary/ordered.lux index 7736202d0..951d6c891 100644 --- a/stdlib/source/test/lux/data/collection/dictionary/ordered.lux +++ b/stdlib/source/test/lux/data/collection/dictionary/ordered.lux @@ -27,7 +27,7 @@ (def .public (dictionary order gen_key gen_value size) (All (_ k v) (-> (Order k) (Random k) (Random v) Nat (Random (/.Dictionary k v)))) - (case size + (when size 0 (random#in (/.empty order)) @@ -75,7 +75,7 @@ (_.coverage [/.empty] (/.empty? (/.empty n.order))) (_.coverage [/.min] - (case [(/.min sample) (list.head sorted_values)] + (when [(/.min sample) (list.head sorted_values)] [{.#None} {.#None}] true @@ -85,7 +85,7 @@ _ false)) (_.coverage [/.max] - (case [(/.max sample) (list.last sorted_values)] + (when [(/.max sample) (list.last sorted_values)] [{.#None} {.#None}] true @@ -116,7 +116,7 @@ (/.size sample+)))))) (_.coverage [/.value] (let [sample+ (/.has extra_key extra_value sample)] - (case [(/.value extra_key sample) + (when [(/.value extra_key sample) (/.value extra_key sample+)] [{.#None} {.#Some actual}] (n.= extra_value actual) diff --git a/stdlib/source/test/lux/data/collection/list.lux b/stdlib/source/test/lux/data/collection/list.lux index 6bb1808f7..bd1e684d7 100644 --- a/stdlib/source/test/lux/data/collection/list.lux +++ b/stdlib/source/test/lux/data/collection/list.lux @@ -77,7 +77,7 @@ [a (lifted (io#in parameter)) b (in subject)] (in (n.+ a b)))) - (pipe.case + (pipe.when (list actual) (n.= expected actual) @@ -169,7 +169,7 @@ has_correct_values!))) (_.coverage [/.item] (/.every? (function (_ [index expected]) - (case (/.item index sample) + (when (/.item index sample) {.#Some actual} (n.= expected actual) @@ -177,13 +177,13 @@ false)) (/.enumeration sample))) (do ! - [index (case size + [index (when size 0 random.nat _ (at ! each (n.% size) random.nat)) .let [changed? (/#= sample (/.revised index ++ sample)) same? (/#= sample (/.revised size ++ sample))]] (_.coverage [/.revised] - (case size + (when size 0 (and changed? same?) _ (not changed?)))) @@ -250,7 +250,7 @@ (,, (with_template [ 
]
                      [(all _.and
                            (_.coverage []
-                             (case [(
 sample) ( sample)]
+                             (when [(
 sample) ( sample)]
                                [{.#Item expected _} {.#Some actual}]
                                (n.= expected actual)
 
@@ -260,7 +260,7 @@
                                _
                                false))
                            (_.coverage []
-                             (case [(
 sample) ( sample)]
+                             (when [(
 sample) ( sample)]
                                [{.#Item _ expected} {.#Some actual}]
                                (/#= (
 expected) actual)
 
@@ -298,7 +298,7 @@
                                    /.size
                                    (n.% 2)
                                    (n.= 0))]
-               (case (/.pairs sample/0)
+               (when (/.pairs sample/0)
                  {.#Some pairs/0}
                  (and even_sized?
                       (n.= (n./ 2 (/.size sample/0))
@@ -384,7 +384,7 @@
       [sample ..random]
       (all _.and
            (_.coverage [/.one]
-             (case [(|> sample
+             (when [(|> sample
                         (/.only n.even?)
                         (/#each (at n.decimal encoded))
                         /.head)
@@ -404,7 +404,7 @@
                      (/#each (at n.decimal encoded)))
                  (/.all choice sample)))
            (_.coverage [/.example]
-             (case (/.example n.even? sample)
+             (when (/.example n.even? sample)
                {.#Some found}
                (n.even? found)
 
diff --git a/stdlib/source/test/lux/data/collection/queue.lux b/stdlib/source/test/lux/data/collection/queue.lux
index b1889edc9..99511bab5 100644
--- a/stdlib/source/test/lux/data/collection/queue.lux
+++ b/stdlib/source/test/lux/data/collection/queue.lux
@@ -60,7 +60,7 @@
                  (and empty_is_empty!
                       all_empty_queues_look_the_same!)))
              (_.coverage [/.front]
-               (case [members (/.front sample)]
+               (when [members (/.front sample)]
                  [{.#Item head tail} {.#Some first}]
                  (n.= head first)
                  
@@ -95,7 +95,7 @@
                       new_member_is_identified!
                       has_expected_order!)))
              (_.coverage [/.next]
-               (case members
+               (when members
                  {.#Item target expected}
                  (let [popped (/.next sample)
 
diff --git a/stdlib/source/test/lux/data/collection/queue/priority.lux b/stdlib/source/test/lux/data/collection/queue/priority.lux
index b0ca6a4f9..b7a1028fe 100644
--- a/stdlib/source/test/lux/data/collection/queue/priority.lux
+++ b/stdlib/source/test/lux/data/collection/queue/priority.lux
@@ -49,14 +49,14 @@
              (_.coverage [/.empty]
                (/.empty? /.empty))
              (_.coverage [/.front]
-               (case (/.front sample)
+               (when (/.front sample)
                  {.#Some first}
                  (n.> 0 (/.size sample))
                  
                  {.#None}
                  (/.empty? sample)))
              (_.coverage [/.member?]
-               (case (/.front sample)
+               (when (/.front sample)
                  {.#Some first}
                  (/.member? n.equivalence sample first)
                  
diff --git a/stdlib/source/test/lux/data/collection/sequence.lux b/stdlib/source/test/lux/data/collection/sequence.lux
index dac8c85a5..a24d05ed6 100644
--- a/stdlib/source/test/lux/data/collection/sequence.lux
+++ b/stdlib/source/test/lux/data/collection/sequence.lux
@@ -94,7 +94,7 @@
             .let [sample (|> sample set.list /.of_list)]]
            (all _.and
                 (_.coverage [/.item]
-                  (case (/.item good_index sample)
+                  (when (/.item good_index sample)
                     {try.#Success member}
                     (/.member? n.equivalence sample member)
                     
@@ -119,7 +119,7 @@
                 (_.coverage [/.index_out_of_bounds]
                   (let [fails! (is (All (_ a) (-> (Try a) Bit))
                                    (function (_ situation)
-                                     (case situation
+                                     (when situation
                                        {try.#Success member}
                                        false
                                        
@@ -201,7 +201,7 @@
                                          (if (n.even? value)
                                            {.#Some (at n.decimal encoded value)}
                                            {.#None})))]
-                        (case [(|> sample
+                        (when [(|> sample
                                    (/.only n.even?)
                                    (/#each (at n.decimal encoded))
                                    (/.item 0))
diff --git a/stdlib/source/test/lux/data/collection/set/ordered.lux b/stdlib/source/test/lux/data/collection/set/ordered.lux
index cc68dbb85..cedc2db15 100644
--- a/stdlib/source/test/lux/data/collection/set/ordered.lux
+++ b/stdlib/source/test/lux/data/collection/set/ordered.lux
@@ -26,7 +26,7 @@
 
 (def .public (random size order gen_value)
   (All (_ a) (-> Nat (Order a) (Random a) (Random (Set a))))
-  (case size
+  (when size
     0
     (random#in (/.empty order))
 
@@ -74,7 +74,7 @@
                        (/#= setL)))
                  (,, (with_template [ ]
                        [(_.coverage []
-                          (case ( setL)
+                          (when ( setL)
                             {.#Some value}
                             (|> setL /.list (list.every? ( value)))
 
diff --git a/stdlib/source/test/lux/data/collection/stack.lux b/stdlib/source/test/lux/data/collection/stack.lux
index 51357230f..22935a5f9 100644
--- a/stdlib/source/test/lux/data/collection/stack.lux
+++ b/stdlib/source/test/lux/data/collection/stack.lux
@@ -45,14 +45,14 @@
              (_.coverage [/.empty]
                (/.empty? /.empty))
              (_.coverage [/.value]
-               (case (/.value sample)
+               (when (/.value sample)
                  {.#None}
                  (/.empty? sample)
                  
                  {.#Some _}
                  (not (/.empty? sample))))
              (_.coverage [/.next]
-               (case (/.next sample)
+               (when (/.next sample)
                  {.#None}
                  (/.empty? sample)
                  
@@ -61,7 +61,7 @@
                      sample
                      (/.top top remaining))))
              (_.coverage [/.top]
-               (case (/.next (/.top expected_top sample))
+               (when (/.next (/.top expected_top sample))
                  {.#Some [actual_top actual_sample]}
                  (and (same? expected_top actual_top)
                       (same? sample actual_sample))
diff --git a/stdlib/source/test/lux/data/collection/tree.lux b/stdlib/source/test/lux/data/collection/tree.lux
index 1193c4e9e..8f7ef89da 100644
--- a/stdlib/source/test/lux/data/collection/tree.lux
+++ b/stdlib/source/test/lux/data/collection/tree.lux
@@ -31,7 +31,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
diff --git a/stdlib/source/test/lux/data/collection/tree/finger.lux b/stdlib/source/test/lux/data/collection/tree/finger.lux
index f291a6e51..ff6e1b62f 100644
--- a/stdlib/source/test/lux/data/collection/tree/finger.lux
+++ b/stdlib/source/test/lux/data/collection/tree/finger.lux
@@ -51,20 +51,20 @@
                                        (at ..builder leaf tag_left expected_left)
                                        (at ..builder leaf tag_right expected_right))))))
              (_.coverage [/.root]
-               (and (case (/.root (at ..builder leaf tag_left expected_left))
+               (and (when (/.root (at ..builder leaf tag_left expected_left))
                       {.#Left actual}
                       (n.= expected_left actual)
                       
                       {.#Right _}
                       false)
-                    (case (/.root (at ..builder branch
+                    (when (/.root (at ..builder branch
                                       (at ..builder leaf tag_left expected_left)
                                       (at ..builder leaf tag_right expected_right)))
                       {.#Left _}
                       false
                       
                       {.#Right [left right]}
-                      (case [(/.root left)
+                      (when [(/.root left)
                              (/.root right)]
                         [{.#Left actual_left} {.#Left actual_right}]
                         (and (n.= expected_left actual_left)
diff --git a/stdlib/source/test/lux/data/format/json.lux b/stdlib/source/test/lux/data/format/json.lux
index d39552093..0b5dca612 100644
--- a/stdlib/source/test/lux/data/format/json.lux
+++ b/stdlib/source/test/lux/data/format/json.lux
@@ -54,7 +54,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
@@ -152,7 +152,7 @@
                   expected_string (random.unicode 1)
                   [boolean_field number_field string_field] (|> (random.set text.hash 3 (random.unicode 3))
                                                                 (at ! each (|>> set.list
-                                                                                (pipe.case
+                                                                                (pipe.when
                                                                                   (list boolean_field number_field string_field)
                                                                                   [boolean_field number_field string_field]
 
@@ -312,7 +312,7 @@
                  (_.coverage [/.Null /.null?]
                    (at bit.equivalence =
                        (/.null? sample)
-                       (case sample
+                       (when sample
                          {/.#Null} true
                          _ false))))
                (do random.monad
@@ -331,7 +331,7 @@
                         object (/.object expected)]]
                  (all _.and
                       (_.coverage [/.object /.fields]
-                        (case (/.fields object)
+                        (when (/.fields object)
                           {try.#Success actual}
                           (at (list.equivalence text.equivalence) =
                               (list#each product.left expected)
@@ -362,7 +362,7 @@
                                     (try.else false))
 
                                 cannot_find_unknown_key!
-                                (case (/.field unknown object)
+                                (when (/.field unknown object)
                                   {try.#Success _}
                                   false
 
diff --git a/stdlib/source/test/lux/data/format/tar.lux b/stdlib/source/test/lux/data/format/tar.lux
index 1101f9ca1..a858db473 100644
--- a/stdlib/source/test/lux/data/format/tar.lux
+++ b/stdlib/source/test/lux/data/format/tar.lux
@@ -47,7 +47,7 @@
                                    /.path_size)]
            (`` (all _.and
                     (_.coverage [/.path /.from_path]
-                      (case (/.path expected)
+                      (when (/.path expected)
                         {try.#Success actual}
                         (text#= expected
                                 (/.from_path actual))
@@ -57,14 +57,14 @@
                     (_.coverage [/.no_path]
                       (text#= "" (/.from_path /.no_path)))
                     (_.coverage [/.path_size /.path_is_too_long]
-                      (case (/.path invalid)
+                      (when (/.path invalid)
                         {try.#Success _}
                         false
 
                         {try.#Failure error}
                         (exception.match? /.path_is_too_long error)))
                     (_.coverage [/.not_ascii]
-                      (case (/.path not_ascii)
+                      (when (/.path not_ascii)
                         {try.#Success actual}
                         false
 
@@ -82,7 +82,7 @@
                                    /.name_size)]
            (`` (all _.and
                     (_.coverage [/.name /.from_name]
-                      (case (/.name expected)
+                      (when (/.name expected)
                         {try.#Success actual}
                         (text#= expected
                                 (/.from_name actual))
@@ -90,14 +90,14 @@
                         {try.#Failure error}
                         false))
                     (_.coverage [/.name_size /.name_is_too_long]
-                      (case (/.name invalid)
+                      (when (/.name invalid)
                         {try.#Success _}
                         false
 
                         {try.#Failure error}
                         (exception.match? /.name_is_too_long error)))
                     (_.coverage [/.not_ascii]
-                      (case (/.name not_ascii)
+                      (when (/.name not_ascii)
                         {try.#Success actual}
                         false
 
@@ -113,7 +113,7 @@
             invalid (|> random.nat (at ! each (n.max /.small_limit)))]
            (`` (all _.and
                     (_.coverage [/.small /.from_small]
-                      (case (/.small expected)
+                      (when (/.small expected)
                         {try.#Success actual}
                         (n.= expected
                              (/.from_small actual))
@@ -121,7 +121,7 @@
                         {try.#Failure error}
                         false))
                     (_.coverage [/.small_limit /.not_a_small_number]
-                      (case (/.small invalid)
+                      (when (/.small invalid)
                         {try.#Success actual}
                         false
 
@@ -137,7 +137,7 @@
             invalid (|> random.nat (at ! each (n.max /.big_limit)))]
            (`` (all _.and
                     (_.coverage [/.big /.from_big]
-                      (case (/.big expected)
+                      (when (/.big expected)
                         {try.#Success actual}
                         (n.= expected
                              (/.from_big actual))
@@ -145,7 +145,7 @@
                         {try.#Failure error}
                         false))
                     (_.coverage [/.big_limit /.not_a_big_number]
-                      (case (/.big invalid)
+                      (when (/.big invalid)
                         {try.#Success actual}
                         false
 
@@ -175,7 +175,7 @@
                              tar (|> (sequence.sequence { expected_path})
                                      (\\format.result /.format)
                                      (.result /.parser))]
-                            (in (case (sequence.list tar)
+                            (in (when (sequence.list tar)
                                   (list { actual_path})
                                   (text#= (/.from_path expected_path)
                                           (/.from_path actual_path))
@@ -204,7 +204,7 @@
                                                                             expected_content]})
                                                  (\\format.result /.format)
                                                  (.result /.parser))]
-                                        (in (case (sequence.list tar)
+                                        (in (when (sequence.list tar)
                                               (list { [actual_path actual_moment actual_mode actual_ownership actual_content]})
                                               (let [seconds (is (-> Instant Int)
                                                                 (|>> instant.relative (duration.ticks duration.second)))]
@@ -262,7 +262,7 @@
                                                                     content]})
                                      (\\format.result /.format)
                                      (.result /.parser))]
-                            (in (case (sequence.list tar)
+                            (in (when (sequence.list tar)
                                   (list {/.#Normal [_ _ actual_mode _ _]})
                                   (n.= (/.mode expected_mode)
                                        (/.mode actual_mode))
@@ -285,7 +285,7 @@
                                                                            content]})
                                             (\\format.result /.format)
                                             (.result /.parser))]
-                                   (in (case (sequence.list tar)
+                                   (in (when (sequence.list tar)
                                          (list {/.#Normal [_ _ actual_mode _ _]})
                                          (n.= (/.mode )
                                               (/.mode actual_mode))
@@ -324,14 +324,14 @@
     (_.for [/.Ownership /.Owner /.ID]
            (all _.and
                 (_.coverage [/.name_size /.name_is_too_long]
-                  (case (/.name invalid)
+                  (when (/.name invalid)
                     {try.#Success _}
                     false
 
                     {try.#Failure error}
                     (exception.match? /.name_is_too_long error)))
                 (_.coverage [/.not_ascii]
-                  (case (/.name not_ascii)
+                  (when (/.name not_ascii)
                     {try.#Success actual}
                     false
 
@@ -352,7 +352,7 @@
                                                                 content]})
                                  (\\format.result /.format)
                                  (.result /.parser))]
-                        (in (case (sequence.list tar)
+                        (in (when (sequence.list tar)
                               (list {/.#Normal [_ _ _ actual_ownership _]})
                               (and (text#= (/.from_name expected)
                                            (/.from_name (the [/.#user /.#name] actual_ownership)))
@@ -376,7 +376,7 @@
                                                                 content]})
                                  (\\format.result /.format)
                                  (.result /.parser))]
-                        (in (case (sequence.list tar)
+                        (in (when (sequence.list tar)
                               (list {/.#Normal [_ _ _ actual_ownership _]})
                               (and (text#= (/.from_name /.anonymous)
                                            (/.from_name (the [/.#user /.#name] actual_ownership)))
@@ -407,7 +407,7 @@
                    (try.else false)))
              (_.coverage [/.invalid_end_of_archive]
                (let [dump (\\format.result /.format sequence.empty)]
-                 (case (.result /.parser (binary#composite dump dump))
+                 (when (.result /.parser (binary#composite dump dump))
                    {try.#Success _}
                    false
                    
diff --git a/stdlib/source/test/lux/data/format/xml.lux b/stdlib/source/test/lux/data/format/xml.lux
index c4cccc987..44e3c2553 100644
--- a/stdlib/source/test/lux/data/format/xml.lux
+++ b/stdlib/source/test/lux/data/format/xml.lux
@@ -35,7 +35,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
diff --git a/stdlib/source/test/lux/data/sum.lux b/stdlib/source/test/lux/data/sum.lux
index 11430bb32..b0956f5ba 100644
--- a/stdlib/source/test/lux/data/sum.lux
+++ b/stdlib/source/test/lux/data/sum.lux
@@ -40,13 +40,13 @@
              (_.coverage [/.left]
                (|> (/.left expected)
                    (is (Or Nat Nat))
-                   (pipe.case
+                   (pipe.when
                      {0 #0 actual} (n.= expected actual)
                      _ false)))
              (_.coverage [/.right]
                (|> (/.right expected)
                    (is (Or Nat Nat))
-                   (pipe.case
+                   (pipe.when
                      {0 #1 actual} (n.= expected actual)
                      _ false)))
              (_.coverage [/.either]
@@ -62,11 +62,11 @@
                (and (|> (/.left expected)
                         (is (Or Nat Nat))
                         (/.then (n.+ shift) (n.- shift))
-                        (pipe.case {0 #0 actual} (n.= (n.+ shift expected) actual) _ false))
+                        (pipe.when {0 #0 actual} (n.= (n.+ shift expected) actual) _ false))
                     (|> (/.right expected)
                         (is (Or Nat Nat))
                         (/.then (n.+ shift) (n.- shift))
-                        (pipe.case {0 #1 actual} (n.= (n.- shift expected) actual) _ false))))
+                        (pipe.when {0 #1 actual} (n.= (n.- shift expected) actual) _ false))))
              (do !
                [size (at ! each (n.% 5) random.nat)
                 expected (random.list size random.nat)]
diff --git a/stdlib/source/test/lux/data/text.lux b/stdlib/source/test/lux/data/text.lux
index dca84b015..97fe18d59 100644
--- a/stdlib/source/test/lux/data/text.lux
+++ b/stdlib/source/test/lux/data/text.lux
@@ -195,7 +195,7 @@
                (do random.monad
                  [sample (random.maybe random.nat)]
                  (_.coverage [\\format.maybe]
-                   (case sample
+                   (when sample
                      {.#None}
                      true
                      
@@ -215,7 +215,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
@@ -224,7 +224,7 @@
 
 (def (should_fail' sample parser exception)
   (All (_ a e) (-> Text (\\parser.Parser a) (Exception e) Bit))
-  (case (\\parser.result parser sample)
+  (when (\\parser.result parser sample)
     {try.#Failure error}
     (exception.match? exception error)
     
@@ -233,7 +233,7 @@
 
 (def (should_fail sample parser)
   (All (_ a) (-> Text (\\parser.Parser a) Bit))
-  (case (\\parser.result parser sample)
+  (when (\\parser.result parser sample)
     {try.#Failure _}
     true
     
@@ -259,7 +259,7 @@
           range (at ! each (|>> (nat.% 50) (nat.+ 10)) random.nat)
           .let [limit (nat.+ offset range)]
           expected (at ! each (|>> (nat.% range) (nat.+ offset) /.of_char) random.nat)
-          out_of_range (case offset
+          out_of_range (when offset
                          0 (at ! each (|>> (nat.% 10) ++ (nat.+ limit) /.of_char) random.nat)
                          _ (at ! each (|>> (nat.% offset) /.of_char) random.nat))]
          (_.coverage [\\parser.range]
@@ -745,9 +745,9 @@
           .let [sample (|> characters set.list /.together)]
           expected (at ! each (nat.% size) random.nat)]
          (_.coverage [/.char]
-           (case (/.char expected sample)
+           (when (/.char expected sample)
              {.#Some char}
-             (case (/.index (/.of_char char) sample)
+             (when (/.index (/.of_char char) sample)
                {.#Some actual}
                (nat.= expected actual)
 
@@ -803,7 +803,7 @@
                (at /.monoid composite post static)
                (/.replaced_once pre post (at /.monoid composite pre static))))
          (_.coverage [/.split_by]
-           (case (/.split_by static (all (at /.monoid composite) pre static post))
+           (when (/.split_by static (all (at /.monoid composite) pre static post))
              {.#Some [left right]}
              (and (at /.equivalence = pre left)
                   (at /.equivalence = post right))
@@ -883,7 +883,7 @@
              (all _.and
                   (_.coverage [/.split_at]
                     (|> (/.split_at sizeL sample)
-                        (pipe.case
+                        (pipe.when
                           {.#Right [_l _r]}
                           (and (/#= sampleL _l)
                                (/#= sampleR _r)
@@ -896,7 +896,7 @@
                          (/.clip sizeL (nat.- sizeL (/.size sample)) sample)
                          (/.clip_since sizeL sample)
                          (/.clip_since 0 sample)]
-                        (pipe.case
+                        (pipe.when
                           [{.#Right _l} {.#Right _r} {.#Right _r'} {.#Right _f}]
                           (and (/#= sampleL _l)
                                (/#= sampleR _r)
diff --git a/stdlib/source/test/lux/data/text/escape.lux b/stdlib/source/test/lux/data/text/escape.lux
index 1ac4b1904..554aaa16f 100644
--- a/stdlib/source/test/lux/data/text/escape.lux
+++ b/stdlib/source/test/lux/data/text/escape.lux
@@ -107,7 +107,7 @@
                  (if (or (/.escapable? left)
                          (/.escapable? right))
                    (let [escaped (/.escaped expected)]
-                     (case (/.un_escaped escaped)
+                     (when (/.un_escaped escaped)
                        {try.#Success un_escaped}
                        (and (not (text#= escaped expected))
                             (text#= un_escaped expected))
@@ -119,7 +119,7 @@
              [dummy (|> (random.char unicode.character)
                         (at ! each text.of_char))]
              (_.coverage [/.dangling_escape]
-               (case (/.un_escaped (format (/.escaped dummy) "\"))
+               (when (/.un_escaped (format (/.escaped dummy) "\"))
                  {try.#Success _}
                  false
 
@@ -130,7 +130,7 @@
                         (random.only (|>> (set.member? ..valid_sigils) not))
                         (at ! each text.of_char))]
              (_.coverage [/.invalid_escape]
-               (case (/.un_escaped (format "\" dummy))
+               (when (/.un_escaped (format "\" dummy))
                  {try.#Success _}
                  false
 
@@ -141,12 +141,12 @@
                             (at ! each (n.% (hex "1000"))))
               code (|> (random.unicode 4)
                        (random.only (function (_ code)
-                                      (case (at n.hex decoded code)
+                                      (when (at n.hex decoded code)
                                         {try.#Failure error} true
                                         {try.#Success _} false))))]
              (_.coverage [/.invalid_unicode_escape]
                (template.let [(!invalid )
-                              [(case (/.un_escaped (format "\u" ))
+                              [(when (/.un_escaped (format "\u" ))
                                  {try.#Success _}
                                  false
 
diff --git a/stdlib/source/test/lux/data/text/regex.lux b/stdlib/source/test/lux/data/text/regex.lux
index d5be70ce1..1b1b8ec95 100644
--- a/stdlib/source/test/lux/data/text/regex.lux
+++ b/stdlib/source/test/lux/data/text/regex.lux
@@ -28,7 +28,7 @@
   (-> (Parser Text) Text Bit)
   (|> input
       (.result regex)
-      (pipe.case
+      (pipe.when
         {try.#Success parsed}
         (text#= parsed input)
 
@@ -39,7 +39,7 @@
   (-> Text (Parser Text) Text Bit)
   (|> input
       (.result regex)
-      (pipe.case
+      (pipe.when
         {try.#Success parsed}
         (text#= test parsed)
 
@@ -50,7 +50,7 @@
   (All (_ a) (-> (Parser a) Text Bit))
   (|> input
       (.result regex)
-      (pipe.case
+      (pipe.when
         {try.#Failure _}
         true
 
@@ -64,7 +64,7 @@
     (macro.with_symbols [g!message g!_]
       (in (list (` (|> (, input)
                        (.result (, regex))
-                       (pipe.case
+                       (pipe.when
                          {try.#Success (, pattern)}
                          true
 
@@ -282,7 +282,7 @@
 (def expands?
   (syntax (_ [form .any])
     (function (_ lux)
-      {try.#Success [lux (list (code.bit (case (expansion.single form lux)
+      {try.#Success [lux (list (code.bit (when (expansion.single form lux)
                                            {try.#Success _}
                                            true
 
@@ -310,7 +310,7 @@
               sample2 (random.unicode 3)
               sample3 (random.unicode 4)]
              (_.coverage [/.pattern]
-               (case (format sample1 "-" sample2 "-" sample3)
+               (when (format sample1 "-" sample2 "-" sample3)
                  (/.pattern "(.{3})-(.{3})-(.{4})"
                             [_ match1 match2 match3])
                  (and (text#= sample1 match1)
diff --git a/stdlib/source/test/lux/debug.lux b/stdlib/source/test/lux/debug.lux
index 6332cfa59..1612f17b4 100644
--- a/stdlib/source/test/lux/debug.lux
+++ b/stdlib/source/test/lux/debug.lux
@@ -78,7 +78,7 @@
     [sample_bit random.bit
      sample_int random.int
      sample_frac random.frac]
-    (in (`` (and (case (/.representation (type_literal [Bit Int Frac])
+    (in (`` (and (when (/.representation (type_literal [Bit Int Frac])
                                          [sample_bit sample_int sample_frac])
                    {try.#Success actual}
                    (text#= (format "[" (%.bit sample_bit)
@@ -186,7 +186,7 @@
                           ))
                     )))
          (_.coverage [/.cannot_represent_value]
-           (case (/.representation (-> Nat Nat) (|>>))
+           (when (/.representation (-> Nat Nat) (|>>))
              {try.#Success representation}
              false
 
@@ -221,7 +221,7 @@
 (def macro_error
   (syntax (_ [macro .any])
     (function (_ compiler)
-      (case ((expansion.complete macro) compiler)
+      (when ((expansion.complete macro) compiler)
         {try.#Failure error}
         {try.#Success [compiler (list (code.text error))]}
         
diff --git a/stdlib/source/test/lux/documentation.lux b/stdlib/source/test/lux/documentation.lux
index 2d162fb2a..f691453e1 100644
--- a/stdlib/source/test/lux/documentation.lux
+++ b/stdlib/source/test/lux/documentation.lux
@@ -25,7 +25,7 @@
 (def macro_error
   (syntax (_ [macro .any])
     (function (_ compiler)
-      {try.#Success [compiler (list (code.bit (case ((expansion.complete macro) compiler)
+      {try.#Success [compiler (list (code.bit (when ((expansion.complete macro) compiler)
                                                 {try.#Failure error}
                                                 true
                                                 
diff --git a/stdlib/source/test/lux/ffi.jvm.lux b/stdlib/source/test/lux/ffi.jvm.lux
index 5b3e2bb80..d7d05321d 100644
--- a/stdlib/source/test/lux/ffi.jvm.lux
+++ b/stdlib/source/test/lux/ffi.jvm.lux
@@ -78,7 +78,7 @@
     (function (_ lux)
       (|> (expansion.single expression)
           (meta.result lux)
-          (pipe.case
+          (pipe.when
             {try.#Success expansion}
             {try.#Failure "OOPS!"}
             
@@ -169,10 +169,10 @@
          bit/0 random.bit]
         (all _.and
              (_.coverage [/.as]
-               (and (case (/.as java/lang/String sample) {.#Some _} true {.#None} false)
-                    (case (/.as java/lang/Long sample) {.#Some _} false {.#None} true)
-                    (case (/.as java/lang/Object sample) {.#Some _} true {.#None} false)
-                    (case (/.as java/lang/Object (/.null)) {.#Some _} false {.#None} true)))
+               (and (when (/.as java/lang/String sample) {.#Some _} true {.#None} false)
+                    (when (/.as java/lang/Long sample) {.#Some _} false {.#None} true)
+                    (when (/.as java/lang/Object sample) {.#Some _} true {.#None} false)
+                    (when (/.as java/lang/Object (/.null)) {.#Some _} false {.#None} true)))
              (_.coverage [/.synchronized]
                (/.synchronized sample true))
              (_.coverage [/.class_for]
@@ -183,7 +183,7 @@
              (_.coverage [/.???]
                (and (|> (/.??? (/.null))
                         (is (Maybe java/lang/Object))
-                        (pipe.case
+                        (pipe.when
                           {.#None}
                           true
                           
@@ -191,7 +191,7 @@
                           false))
                     (|> (/.??? sample)
                         (is (Maybe java/lang/Object))
-                        (pipe.case
+                        (pipe.when
                           {.#Some _}
                           true
                           
@@ -331,14 +331,14 @@
                          (/.as_long (.int expected))
                          (panic! "YOLO"))))
            example/1!
-           (and (case (test/TestInterface1::actual1 (/.as_boolean false) object/1)
+           (and (when (test/TestInterface1::actual1 (/.as_boolean false) object/1)
                   {try.#Success actual}
                   (same? (is Any expected)
                          (is Any actual))
                   
                   {try.#Failure error}
                   false)
-                (case (test/TestInterface1::actual1 (/.as_boolean true) object/1)
+                (when (test/TestInterface1::actual1 (/.as_boolean true) object/1)
                   {try.#Success actual}
                   false
                   
@@ -572,14 +572,14 @@
 
            object/1 (test/TestClass1::new (/.as_long (.int expected)))
            example/1!
-           (and (case (test/TestInterface1::actual1 (/.as_boolean false) object/1)
+           (and (when (test/TestInterface1::actual1 (/.as_boolean false) object/1)
                   {try.#Success actual}
                   (n.= expected
                        (.nat (/.of_long actual)))
                   
                   {try.#Failure error}
                   false)
-                (case (test/TestInterface1::actual1 (/.as_boolean true) object/1)
+                (when (test/TestInterface1::actual1 (/.as_boolean true) object/1)
                   {try.#Success actual}
                   false
                   
@@ -680,7 +680,7 @@
     (function (_ lux)
       (|> (expansion.single expression)
           (meta.result lux)
-          (pipe.case
+          (pipe.when
             {try.#Success expansion}
             true
             
@@ -720,7 +720,7 @@
                       (try.else false))
                   (|> (list (code.local var/2))
                       (.result type_variable)
-                      (pipe.case
+                      (pipe.when
                         {try.#Failure error}
                         (exception.match? /.unknown_type_variable error)
                         
diff --git a/stdlib/source/test/lux/ffi.lua.lux b/stdlib/source/test/lux/ffi.lua.lux
index a3a036d34..d2d81a6b3 100644
--- a/stdlib/source/test/lux/ffi.lua.lux
+++ b/stdlib/source/test/lux/ffi.lua.lux
@@ -58,7 +58,7 @@
                          (is (Ex (_ a) (/.Object a))))
                      true))
                  (_.coverage [/.import]
-                   (case (io.run! (..os/getenv string))
+                   (when (io.run! (..os/getenv string))
                      {.#Some _} true
                      {.#None} true))
 
diff --git a/stdlib/source/test/lux/ffi.old.lux b/stdlib/source/test/lux/ffi.old.lux
index ce7164514..5feb469ec 100644
--- a/stdlib/source/test/lux/ffi.old.lux
+++ b/stdlib/source/test/lux/ffi.old.lux
@@ -184,14 +184,14 @@
                 (not (/.null? sample))))
          (_.coverage [/.???]
            (and (|> (is (Maybe java/lang/Object) (/.??? (/.null)))
-                    (pipe.case
+                    (pipe.when
                       {.#None}
                       true
                       
                       _
                       false))
                 (|> (is (Maybe java/lang/Object) (/.??? sample))
-                    (pipe.case
+                    (pipe.when
                       {.#Some _}
                       true
                       
@@ -210,10 +210,10 @@
      increase random.int]
     (all _.and
          (_.coverage [/.as]
-           (and (case (/.as java/lang/String sample) {.#Some _} true {.#None} false)
-                (case (/.as java/lang/Long sample) {.#Some _} false {.#None} true)
-                (case (/.as java/lang/Object sample) {.#Some _} true {.#None} false)
-                (case (/.as java/lang/Object (/.null)) {.#Some _} false {.#None} true)))
+           (and (when (/.as java/lang/String sample) {.#Some _} true {.#None} false)
+                (when (/.as java/lang/Long sample) {.#Some _} false {.#None} true)
+                (when (/.as java/lang/Object sample) {.#Some _} true {.#None} false)
+                (when (/.as java/lang/Object (/.null)) {.#Some _} false {.#None} true)))
          (_.coverage [/.synchronized]
            (/.synchronized sample true))
          (_.coverage [/.class_for /.import]
diff --git a/stdlib/source/test/lux/math/logic/fuzzy.lux b/stdlib/source/test/lux/math/logic/fuzzy.lux
index dd2f7d00a..345578ead 100644
--- a/stdlib/source/test/lux/math/logic/fuzzy.lux
+++ b/stdlib/source/test/lux/math/logic/fuzzy.lux
@@ -92,7 +92,7 @@
          (random.set r.hash 4)
          (at ! each (|>> set.list (list.sorted r.<)))
          (random.one (function (_ thresholds)
-                       (case thresholds
+                       (when thresholds
                          (list threshold_0 threshold_1 threshold_2 threshold_3)
                          {.#Some [threshold_0 threshold_1 threshold_2 threshold_3]}
 
@@ -176,7 +176,7 @@
              (random.set r.hash 4)
              (at ! each (|>> set.list (list.sorted r.<)))
              (random.one (function (_ thresholds)
-                           (case thresholds
+                           (when thresholds
                              (list threshold_0 threshold_1 threshold_2 threshold_3)
                              {.#Some [threshold_0 threshold_1 threshold_2 threshold_3]}
 
diff --git a/stdlib/source/test/lux/math/modular.lux b/stdlib/source/test/lux/math/modular.lux
index 2e959b428..44610bd3c 100644
--- a/stdlib/source/test/lux/math/modular.lux
+++ b/stdlib/source/test/lux/math/modular.lux
@@ -66,7 +66,7 @@
                         ($codec.spec /.equivalence (/.codec subject::%) (..random subject::%)))
 
                  (_.coverage [/.incorrect_modulus]
-                   (case (|> param
+                   (when (|> param
                              (at (/.codec param::%) encoded)
                              (at (/.codec subject::%) decoded))
                      {try.#Failure error}
@@ -98,7 +98,7 @@
                    (let [one (/.modular (/.modulus subject) +1)
                          co_prime? (i.co_prime? (//.divisor (/.modulus subject))
                                                 (/.value subject))]
-                     (case (/.inverse subject)
+                     (when (/.inverse subject)
                        {.#Some subject^-1}
                        (and co_prime?
                             (|> subject
@@ -118,7 +118,7 @@
                                  adapt
                                  (/.= subject))))))
                  (_.coverage [/.moduli_are_not_equal]
-                   (case (/.adapter subject::% param::%)
+                   (when (/.adapter subject::% param::%)
                      {try.#Failure error}
                      (exception.match? /.moduli_are_not_equal error)
                      
diff --git a/stdlib/source/test/lux/math/modulus.lux b/stdlib/source/test/lux/math/modulus.lux
index c1f61a289..49c406b9b 100644
--- a/stdlib/source/test/lux/math/modulus.lux
+++ b/stdlib/source/test/lux/math/modulus.lux
@@ -23,7 +23,7 @@
   (syntax (_ [])
     (do meta.monad
       [divisor meta.seed]
-      (in (list (code.int (case divisor
+      (in (list (code.int (when divisor
                             0 +1
                             _ (.int divisor))))))))
 
@@ -43,14 +43,14 @@
          dividend random.int]
         (all _.and
              (_.coverage [/.modulus /.divisor]
-               (case (/.modulus divisor)
+               (when (/.modulus divisor)
                  {try.#Success modulus}
                  (i.= divisor (/.divisor modulus))
                  
                  {try.#Failure error}
                  (i.= +0 divisor)))
              (_.coverage [/.zero_cannot_be_a_modulus]
-               (case (/.modulus +0)
+               (when (/.modulus +0)
                  {try.#Failure error}
                  (exception.match? /.zero_cannot_be_a_modulus error)
 
diff --git a/stdlib/source/test/lux/math/number.lux b/stdlib/source/test/lux/math/number.lux
index d5d9fb557..536448d48 100644
--- a/stdlib/source/test/lux/math/number.lux
+++ b/stdlib/source/test/lux/math/number.lux
@@ -35,7 +35,7 @@
       (all _.and
            (_.coverage [/.bin]
              (`` (and (,, (with_template [<=>  ]
-                            [(case (at  decoded (..clean_commas ))
+                            [(when (at  decoded (..clean_commas ))
                                {try.#Success actual}
                                (<=> (/.bin ) actual)
 
@@ -54,7 +54,7 @@
                             )))))
            (_.coverage [/.oct]
              (`` (and (,, (with_template [<=>  ]
-                            [(case (at  decoded (..clean_commas ))
+                            [(when (at  decoded (..clean_commas ))
                                {try.#Success actual}
                                (<=> (/.oct ) actual)
 
@@ -73,7 +73,7 @@
                             )))))
            (_.coverage [/.hex]
              (`` (and (,, (with_template [<=>  ]
-                            [(case (at  decoded (..clean_commas ))
+                            [(when (at  decoded (..clean_commas ))
                                {try.#Success actual}
                                (<=> (/.hex ) actual)
 
diff --git a/stdlib/source/test/lux/math/number/i64.lux b/stdlib/source/test/lux/math/number/i64.lux
index 6b4081342..025c41346 100644
--- a/stdlib/source/test/lux/math/number/i64.lux
+++ b/stdlib/source/test/lux/math/number/i64.lux
@@ -103,7 +103,7 @@
                 .let [spare (n.- size /.width)]
                 offset (at ! each (n.% spare) random.nat)]
                (_.coverage [/.region]
-                 (case size
+                 (when size
                    0 (/#= /.false (/.region offset size))
                    _ (/#= (|> pattern
                               ... NNNNYYYYNNNN
@@ -124,7 +124,7 @@
   (_.for [/.Sub]
          (do [! random.monad]
            [size (at ! each (n.% /.width) random.nat)]
-           (case (/.sub size)
+           (when (/.sub size)
              {.#None}
              (_.coverage [/.sub]
                (n.= 0 size))
diff --git a/stdlib/source/test/lux/math/number/ratio.lux b/stdlib/source/test/lux/math/number/ratio.lux
index b81cc91c6..74c9a9ca7 100644
--- a/stdlib/source/test/lux/math/number/ratio.lux
+++ b/stdlib/source/test/lux/math/number/ratio.lux
@@ -79,7 +79,7 @@
                              (maybe.else false))
 
                          with_denominator!
-                         (case (/.nat (/.ratio numerator denominator))
+                         (when (/.nat (/.ratio numerator denominator))
                            {.#Some factor}
                            (and (n.= 0 (n.% denominator numerator))
                                 (n.= numerator (n.* factor denominator)))
@@ -111,7 +111,7 @@
                          div (|> right (/.- rem) (/./ left))]
                      (and (/.= right
                                (|> div (/.* left) (/.+ rem)))
-                          (case (/.nat div)
+                          (when (/.nat div)
                             {.#Some _} true
                             {.#None}   false)))))
                (do random.monad
diff --git a/stdlib/source/test/lux/meta.lux b/stdlib/source/test/lux/meta.lux
index 98081de7f..fa3fd7f7a 100644
--- a/stdlib/source/test/lux/meta.lux
+++ b/stdlib/source/test/lux/meta.lux
@@ -77,7 +77,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
         true
        _ false)]))
 
@@ -432,7 +432,7 @@
                                            (list [expected_short
                                                   {.#Alias [expected_macro_module expected_short]}]))
                        macro_globals (is (List [Text .Global])
-                                         (case def_type
+                                         (when def_type
                                            {.#Some def_type}
                                            (list [expected_short
                                                   {.#Definition [exported? def_type expected_value]}])
@@ -548,7 +548,7 @@
                                            (list [expected_short
                                                   {.#Alias [expected_macro_module expected_short]}]))
                        macro_globals (is (List [Text .Global])
-                                         (case def_type
+                                         (when def_type
                                            {.#Some def_type}
                                            (list [expected_short
                                                   {.#Definition [exported? def_type expected_value]}])
@@ -846,7 +846,7 @@
                                               (random.set text.hash 5)
                                               (at ! each set.list)
                                               (random.one (function (_ values)
-                                                            (case values
+                                                            (when values
                                                               (list name_0 name_1 name_2 name_3 name_4)
                                                               {.#Some [name_0 name_1 name_2 name_3 name_4]}
 
@@ -971,7 +971,7 @@
 (def (comparison init)
   (-> Lux (Comparison Meta))
   (function (_ == left right)
-    (case [(/.result init left)
+    (when [(/.result init left)
            (/.result init right)]
       [{try.#Success left} {try.#Success right}]
       (== left right)
diff --git a/stdlib/source/test/lux/meta/code.lux b/stdlib/source/test/lux/meta/code.lux
index 80c1bbe65..7e35b1c9f 100644
--- a/stdlib/source/test/lux/meta/code.lux
+++ b/stdlib/source/test/lux/meta/code.lux
@@ -39,7 +39,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
@@ -207,7 +207,7 @@
                             (text.size source_code))
         start (is Source
                   [location.dummy 0 source_code])]
-    (case (parse start)
+    (when (parse start)
       {.#Left [end error]}
       {try.#Failure error}
       
@@ -250,7 +250,7 @@
                  [(do [! random.monad]
                     [expected ]
                     (_.coverage []
-                      (and (case (..read (/.format ( expected)))
+                      (and (when (..read (/.format ( expected)))
                              {try.#Success actual}
                              (at /.equivalence =
                                  actual
@@ -276,7 +276,7 @@
                  [(do [! random.monad]
                     [expected ]
                     (_.coverage []
-                      (and (case (..read (/.format ( expected)))
+                      (and (when (..read (/.format ( expected)))
                              {try.#Success actual}
                              (at /.equivalence =
                                  actual
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis.lux
index 4fdb983a1..69e3885f8 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis.lux
@@ -67,7 +67,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
 
@@ -91,7 +91,7 @@
                    (_.coverage [\\parser.result \\parser.any]
                      (|> (list expected)
                          (\\parser.result \\parser.any)
-                         (pipe.case
+                         (pipe.when
                            {try.#Success actual}
                            (at /.equivalence = expected actual)
 
@@ -103,7 +103,7 @@
                           (_.coverage []
                             (|> (list ( expected))
                                 (\\parser.result )
-                                (pipe.case
+                                (pipe.when
                                   {try.#Success actual}
                                   (<=> expected actual)
 
@@ -131,7 +131,7 @@
                    (_.coverage [\\parser.tuple]
                      (|> (list (/.tuple (list (/.bit expected))))
                          (\\parser.result (\\parser.tuple \\parser.bit))
-                         (pipe.case
+                         (pipe.when
                            {try.#Success actual}
                            (bit#= expected actual)
 
@@ -160,7 +160,7 @@
                    (_.coverage [\\parser.cannot_parse]
                      (and (|> (list (/.bit expected))
                               (\\parser.result \\parser.nat)
-                              (pipe.case
+                              (pipe.when
                                 {try.#Success _}
                                 false
 
@@ -168,7 +168,7 @@
                                 (exception.match? \\parser.cannot_parse error)))
                           (|> (list)
                               (\\parser.result \\parser.bit)
-                              (pipe.case
+                              (pipe.when
                                 {try.#Success _}
                                 false
 
@@ -179,7 +179,7 @@
                    (_.coverage [\\parser.unconsumed_input]
                      (|> (list (/.bit expected) (/.bit expected))
                          (\\parser.result \\parser.bit)
-                         (pipe.case
+                         (pipe.when
                            {try.#Success _}
                            false
 
@@ -205,7 +205,7 @@
   (-> Nat (Random /.Analysis))
   (<| random.rec
       (function (_ random))
-      (let [random|case (all random.and
+      (let [random|when (all random.and
                              random
                              (..random_match multiplicity random)
                              )
@@ -225,7 +225,7 @@
            /simple.random
            (/complex.random multiplicity random)
            /reference.random
-           random|case
+           random|when
            random|function
            random|apply
            random|extension
@@ -242,7 +242,7 @@
      text (random.lower_case 1)]
     (`` (all _.and
              (_.coverage [/.unit]
-               (case (/.unit)
+               (when (/.unit)
                  (/.unit)
                  true
                  
@@ -250,7 +250,7 @@
                  false))
              (,, (with_template [ ]
                    [(_.coverage []
-                      (case ( )
+                      (when ( )
                         ( actual)
                         (same?  actual)
                         
@@ -277,7 +277,7 @@
            (let [expected (if expected_right?
                             expected_right
                             expected_left)]
-             (case (/.variant [expected_lefts expected_right? expected])
+             (when (/.variant [expected_lefts expected_right? expected])
                (/.variant [actual_lefts actual_right? actual])
                (and (same? expected_lefts actual_lefts)
                     (same? expected_right? actual_right?)
@@ -286,7 +286,7 @@
                _
                false)))
          (_.coverage [/.tuple]
-           (case (/.tuple (list expected_left expected_right))
+           (when (/.tuple (list expected_left expected_right))
              (/.tuple (list actual_left actual_right))
              (and (same? expected_left actual_left)
                   (same? expected_right actual_right))
@@ -304,7 +304,7 @@
     (`` (all _.and
              (,, (with_template [ ]
                    [(_.coverage []
-                      (case ( )
+                      (when ( )
                         ( actual)
                         (same?  actual)
 
@@ -320,7 +320,7 @@
 
 (def tagged?
   (template (_  )
-    [(case 
+    [(when 
        { _}
        true
 
@@ -336,7 +336,7 @@
      expected_parameter/1 (..random 2)]
     (all _.and
          (_.coverage [/.reified /.reification]
-           (case (|> [expected_abstraction (list expected_parameter/0 expected_parameter/1)]
+           (when (|> [expected_abstraction (list expected_parameter/0 expected_parameter/1)]
                      /.reified
                      /.reification)
              [actual_abstraction (list actual_parameter/0 actual_parameter/1)]
@@ -347,7 +347,7 @@
              _
              false))
          (_.coverage [/.no_op]
-           (case (/.no_op expected_parameter/0)
+           (when (/.no_op expected_parameter/0)
              (/.no_op actual)
              (same? expected_parameter/0 actual)
 
@@ -355,15 +355,15 @@
              false))
          )))
 
-(def test|case
+(def test|when
   Test
   (do random.monad
     [expected_input (..random 2)
      expected_match (random_match 2 (..random 2))]
     (all _.and
-         (_.coverage [/.case]
-           (case (/.case [expected_input expected_match])
-             (/.case [actual_input actual_match])
+         (_.coverage [/.when]
+           (when (/.when [expected_input expected_match])
+             (/.when [actual_input actual_match])
              (and (same? expected_input actual_input)
                   (same? expected_match actual_match))
 
@@ -405,7 +405,7 @@
              (|> (/.failure expected_error)
                  (phase.result [extension.#bundle extension.empty
                                 extension.#state state/0])
-                 (pipe.case
+                 (pipe.when
                    {try.#Failure actual_error}
                    (and (text.contains? expected_error actual_error)
                         (text.contains? (location.format location/0) actual_error))
@@ -416,7 +416,7 @@
              (|> (/.except  [])
                  (phase.result [extension.#bundle extension.empty
                                 extension.#state state/0])
-                 (pipe.case
+                 (pipe.when
                    {try.#Failure actual_error}
                    (and (text.contains? (exception.error  []) actual_error)
                         (text.contains? (location.format location/0) actual_error))
@@ -428,7 +428,7 @@
                  (/.with_exception  [])
                  (phase.result [extension.#bundle extension.empty
                                 extension.#state state/0])
-                 (pipe.case
+                 (pipe.when
                    {try.#Failure actual_error}
                    (and (text.contains? expected_error actual_error)
                         (text.contains? (exception.error  []) actual_error)
@@ -440,7 +440,7 @@
              (and (|> (/.assertion  [] false)
                       (phase.result [extension.#bundle extension.empty
                                      extension.#state state/0])
-                      (pipe.case
+                      (pipe.when
                         {try.#Failure actual_error}
                         (and (text.contains? (exception.error  []) actual_error)
                              (text.contains? (location.format location/0) actual_error))
@@ -450,7 +450,7 @@
                   (|> (/.assertion  [] true)
                       (phase.result [extension.#bundle extension.empty
                                      extension.#state state/0])
-                      (pipe.case
+                      (pipe.when
                         {try.#Success _}
                         true
 
@@ -496,7 +496,7 @@
                   (list.empty? (the .#modules it))
                   (list.empty? (the .#scopes it))
                   (list.empty? (the [.#type_context .#var_bindings] it))
-                  (case (the .#source it)
+                  (when (the .#source it)
                     [location 0 ""]
                     (same? location.dummy location)
 
@@ -508,7 +508,7 @@
                  (extension.read (|>> (the .#current_module) (maybe.else ""))))
                (phase.result [extension.#bundle extension.empty
                               extension.#state state])
-               (pipe.case
+               (pipe.when
                  {try.#Success actual}
                  (same? expected_module actual)
 
@@ -535,7 +535,7 @@
                    (extension.read (the .#location)))
                  (phase.result [extension.#bundle extension.empty
                                 extension.#state state])
-                 (pipe.case
+                 (pipe.when
                    {try.#Success actual}
                    (same? expected actual)
 
@@ -564,7 +564,7 @@
                    (extension.read (the .#source)))
                  (phase.result [extension.#bundle extension.empty
                                 extension.#state state])
-                 (pipe.case
+                 (pipe.when
                    {try.#Success actual}
                    (same? expected actual)
 
@@ -605,7 +605,7 @@
              (_.for [/.Reification]
                     ..test|reification)
              (_.for [/.Branch /.Branch' /.Match /.Match']
-                    ..test|case)
+                    ..test|when)
              (_.for [/.Operation /.Phase /.Handler /.Bundle]
                     ..test|phase)
              (_.for [/.State+]
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/coverage.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/coverage.lux
index 7272d6c98..0268893df 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/coverage.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/coverage.lux
@@ -60,11 +60,11 @@
            (all random.and
                 (random.maybe (random#in ..spread))
                 (do [! random.monad]
-                  [cases ..random_tag
-                   cases (random.set n.hash cases ..random_tag)]
-                  (|> cases
+                  [whens ..random_tag
+                   whens (random.set n.hash whens ..random_tag)]
+                  (|> whens
                       set.list
-                      (monad.each ! (function (_ case) (at ! each (|>> [case]) again)))
+                      (monad.each ! (function (_ when) (at ! each (|>> [when]) again)))
                       (at ! each (dictionary.of_list n.hash))))
                 )
            (random.and again again)
@@ -121,7 +121,7 @@
                  (in [(|> coverages
                           (list.only (|>> /.exhaustive? not))
                           list.reversed
-                          (pipe.case
+                          (pipe.when
                             {.#End}
                             {/.#Exhaustive}
                             
@@ -140,7 +140,7 @@
 
 (def (failure? exception it)
   (All (_ a) (-> (Exception a) (Try /.Coverage) Bit))
-  (case it
+  (when it
     {try.#Failure error}
     (exception.match? exception error)
 
@@ -212,22 +212,22 @@
          .let [random_tag (random#each (n.% expected_maximum) random.nat)]
          tag/0 random_tag
          tag/1 (random.only (|>> (n.= tag/0) not) random_tag)
-         .let [cases (dictionary.of_list n.hash (list [tag/0 expected/0]
+         .let [whens (dictionary.of_list n.hash (list [tag/0 expected/0]
                                                       [tag/1 expected/1]))
                expected_minimum (++ (n.max tag/0 tag/1))]]
         (all _.and
              (_.coverage [/.minimum]
-               (and (n.= expected_minimum (/.minimum [{.#None} cases]))
-                    (n.= expected_maximum (/.minimum [{.#Some expected_maximum} cases]))))
+               (and (n.= expected_minimum (/.minimum [{.#None} whens]))
+                    (n.= expected_maximum (/.minimum [{.#Some expected_maximum} whens]))))
              (_.coverage [/.maximum]
-               (and (n.= n#top (/.maximum [{.#None} cases]))
-                    (n.= expected_maximum (/.maximum [{.#Some expected_maximum} cases]))))
+               (and (n.= n#top (/.maximum [{.#None} whens]))
+                    (n.= expected_maximum (/.maximum [{.#Some expected_maximum} whens]))))
              ))))
 
 (def random_value_pattern
   (Random [/.Coverage Pattern])
   (random.only (function (_ [coverage pattern])
-                 (case coverage
+                 (when coverage
                    (^.or {/.#Alt _} {/.#Seq _})
                    false
 
@@ -245,7 +245,7 @@
          [expected/2 pattern/2] (random.only (all predicate.and
                                                   (|>> product.left (/#= expected/0) not)
                                                   (|>> product.left (/#= expected/1) not)
-                                                  (|>> product.left (pipe.case {/.#Variant _} false _ true)))
+                                                  (|>> product.left (pipe.when {/.#Variant _} false _ true)))
                                              ..random_value_pattern)
 
          bit random.bit
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/inference.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/inference.lux
index 127af213b..9fa7c48ba 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/inference.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/inference.lux
@@ -75,7 +75,7 @@
 
 (def (fails? exception try)
   (All (_ e a) (-> (Exception e) (Try a) Bit))
-  (case try
+  (when try
     {try.#Success _}
     false
     
@@ -239,7 +239,7 @@
                                        [inferT (/.variant lefts right? variant)
                                         [_ [it _]] (|> (/.general archive.empty ..analysis inferT (list term))
                                                        //type.inferring)]
-                                       (case inferred
+                                       (when inferred
                                          {.#Some inferred}
                                          (//type.check
                                           (do check.monad
@@ -339,7 +339,7 @@
                                [inference (/.record arity record)
                                 [_ [it _]] (|> (/.general archive.empty ..analysis inference terms)
                                                //type.inferring)]
-                               (case expected
+                               (when expected
                                  {.#Some expected}
                                  (//type.check
                                   (do check.monad
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/macro.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/macro.lux
index 2d29df1d8..8c93097e9 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/macro.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/macro.lux
@@ -65,7 +65,7 @@
          .let [singular (<| (as Macro)
                             (is Macro')
                             (function (_ inputs state)
-                              (case (list.item choice inputs)
+                              (when (list.item choice inputs)
                                 {.#Some it}
                                 {try.#Success [state (list it)]}
 
@@ -87,7 +87,7 @@
            (_.coverage [/.expansion_failed]
              (|> (/.expansion ..expander name singular (list))
                  (meta.result lux)
-                 (pipe.case
+                 (pipe.when
                    {try.#Failure it}
                    (and (text.contains? expected_error it)
                         (text.contains? (the exception.#label /.expansion_failed) it))
@@ -102,7 +102,7 @@
            (_.coverage [/.must_have_single_expansion]
              (|> (/.single_expansion ..expander name multiple (list mono))
                  (meta.result lux)
-                 (pipe.case
+                 (pipe.when
                    {try.#Failure it}
                    (text.contains? (the exception.#label /.must_have_single_expansion) it)
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/module.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/module.lux
index 4bb9269cf..58a2e03fa 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/module.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/module.lux
@@ -51,7 +51,7 @@
        (list.empty? (the .#module_aliases it))
        (list.empty? (the .#definitions it))
        (list.empty? (the .#imports it))
-       (case (the .#module_state it)
+       (when (the .#module_state it)
          {.#Active}
          true
          
@@ -122,7 +122,7 @@
                  (in it))
                (/phase.result state)
                (try#each (|>> (the .#module_aliases)
-                              (pipe.case
+                              (pipe.when
                                 (list [actual_alias actual_import])
                                 (and (same? expected_alias actual_alias)
                                      (same? expected_import actual_import))
@@ -166,7 +166,7 @@
                                    [_ (
 name)]
                                    ( name)))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _}
                                  false
                                  
@@ -184,7 +184,7 @@
                (and (,, (with_template []
                           [(|> ( name)
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _}
                                  false
                                  
@@ -225,7 +225,7 @@
                           [(|> (/.with hash module_name
                                  (/.define def_name ))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _} true
                                  {try.#Failure _} false))]
 
@@ -239,7 +239,7 @@
                             [_ (/.define def_name definition)]
                             (/.define alias_name alias)))
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} true
                           {try.#Failure _} false)))))
          (_.coverage [/.cannot_define_more_than_once]
@@ -249,7 +249,7 @@
                                    [_ (/.define def_name )]
                                    (/.define def_name )))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _} false
                                  {try.#Failure _} true))]
 
@@ -264,7 +264,7 @@
                              _ (/.define alias_name alias)]
                             (/.define alias_name alias)))
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} false
                           {try.#Failure _} true)))))
          )))
@@ -299,7 +299,7 @@
                                    (monad.each ! (|>> [module_name]  /extension.lifted)
                                                (list.partial labels|head labels|tail))))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _} 
                                  {try.#Failure _} (not )))]
 
@@ -315,7 +315,7 @@
                                     _ (/.define def_name {.#Type [public? it { [labels|head labels|tail]}]})]
                                    (/.declare_labels  (list.partial labels|head labels|tail) public? it)))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _}
                                  false
                                  
@@ -332,7 +332,7 @@
                                     _ (/.define def_name {.#Type [public? it { [labels|head labels|tail]}]})]
                                    (/.declare_labels  (list.partial labels|head labels|tail) public? it)))
                                (/phase.result state)
-                               (pipe.case
+                               (pipe.when
                                  {try.#Success _}
                                  false
                                  
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/pattern.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/pattern.lux
index 74faec932..a228e3fd3 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/pattern.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/pattern.lux
@@ -56,7 +56,7 @@
                  (bit#= (at /.equivalence = left right)
                         (text#= (/.format left) (/.format right))))
                (_.coverage [/.unit]
-                 (case (/.unit)
+                 (when (/.unit)
                    (/.unit)
                    true
 
@@ -64,7 +64,7 @@
                    false))
                (,, (with_template [ ]
                      [(_.coverage []
-                        (case ( )
+                        (when ( )
                           ( actual)
                           (same?  actual)
 
@@ -80,7 +80,7 @@
                      [/.text expected_text]
                      ))
                (_.coverage [/.variant]
-                 (case (/.variant [expected_lefts expected_right? (/.text expected_text)])
+                 (when (/.variant [expected_lefts expected_right? (/.text expected_text)])
                    (/.variant [actual_lefts actual_right? (/.text actual_text)])
                    (and (same? expected_lefts actual_lefts)
                         (same? expected_right? actual_right?)
@@ -89,7 +89,7 @@
                    _
                    false))
                (_.coverage [/.tuple]
-                 (case (/.tuple (list (/.bit expected_bit)
+                 (when (/.tuple (list (/.bit expected_bit)
                                       (/.nat expected_nat)
                                       (/.int expected_int)
                                       (/.rev expected_rev)
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/scope.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/scope.lux
index bc2c63519..fe46fa6ae 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/scope.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/scope.lux
@@ -38,7 +38,7 @@
   [(def ( expected_type expected_register [actual_type actual_var])
      (-> Type Register [Type Variable] Bit)
      (and (same? expected_type actual_type)
-          (case actual_var
+          (when actual_var
             { actual_register}
             (n.= expected_register actual_register)
             
@@ -66,7 +66,7 @@
                    /.with
                    (//phase.result state)
                    (try#each (|>> product.right
-                                  (pipe.case
+                                  (pipe.when
                                     {.#None} true
                                     {.#Some _} false)))
                    (try.else false)))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/type.lux b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/type.lux
index 8afc7c8fc..c360ea593 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/analysis/type.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/analysis/type.lux
@@ -59,7 +59,7 @@
                         (/module.with 0 module)
                         (/phase#each product.right)
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} true
                           {try.#Failure _} false))
                     (|> (/.inference dummy)
@@ -67,7 +67,7 @@
                         (/module.with 0 module)
                         (/phase#each product.right)
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} false
                           {try.#Failure _} true))
                     (|> (/.inference expected)
@@ -75,7 +75,7 @@
                         (/module.with 0 module)
                         (/phase#each product.right)
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} false
                           {try.#Failure _} true))))
              (_.coverage [/.inferring]
@@ -96,7 +96,7 @@
                    (/module.with 0 module)
                    (/phase#each product.right)
                    (/phase.result state)
-                   (pipe.case
+                   (pipe.when
                      {try.#Success _} true
                      {try.#Failure _} false)))
              (_.coverage [/.existential /.existential?]
@@ -117,7 +117,7 @@
                         (/module.with 0 module)
                         (/phase#each product.right)
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} true
                           {try.#Failure _} false))
                     (|> (do /phase.monad
@@ -130,7 +130,7 @@
                         (/module.with 0 module)
                         (/phase#each product.right)
                         (/phase.result state)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success _} false
                           {try.#Failure _} true))))
              ))))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis.lux
index 7595b7a87..06fc6be98 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis.lux
@@ -46,7 +46,7 @@
   ["[1][0]" complex]
   ["[1][0]" reference]
   ["[1][0]" function]
-  ["[1][0]" case]])
+  ["[1][0]" when]])
 
 (def (eval archive type term)
   Eval
@@ -65,7 +65,7 @@
                          (/.phase ..expander archive.empty)
                          //type.inferring)]
           (in (and (type#= .Any :it:)
-                   (case it
+                   (when it
                      (//.unit)
                      true
 
@@ -88,7 +88,7 @@
                                          (/.phase ..expander archive.empty)
                                          //type.inferring)]
                           (in (and (type#=  :it:)
-                                   (case it
+                                   (when it
                                      ( it)
                                      (same?  it)
 
@@ -129,7 +129,7 @@
                        [it (|> (code.variant (list (code.nat 0) (code.bit false) (` [])))
                                (/.phase ..expander archive.empty)
                                (//type.expecting :variant:))]
-                       (in (case it
+                       (in (when it
                              (//.variant [0 .false (//.unit)])
                              true
 
@@ -145,7 +145,7 @@
                               [it (|> (code.variant (list (code.nat ) (code.bit ) ( )))
                                       (/.phase ..expander archive.empty)
                                       (//type.expecting :variant:))]
-                              (in (case it
+                              (in (when it
                                     (//.variant [  ( actual)])
                                     (same?  actual)
 
@@ -171,7 +171,7 @@
                it (|> (code.variant (list (code.nat 0) (code.bit false)))
                       (/.phase ..expander archive.empty)
                       (//type.expecting :either:))]
-              (in (case it
+              (in (when it
                     (//.variant [0 .false (//.unit)])
                     true
 
@@ -197,7 +197,7 @@
                                           (code.text text/0)))
                       (/.phase ..expander archive.empty)
                       (//type.expecting :either:))]
-              (in (case it
+              (in (when it
                     (//.variant [0 #1 (//.tuple (list (//.unit)
                                                       (//.bit bit/?)
                                                       (//.nat nat/?)
@@ -243,7 +243,7 @@
                                       //type.inferring)]
                        (in (and (type#= :variant:
                                         :it:)
-                                (case it
+                                (when it
                                   (//.variant [0 .false (//.unit)])
                                   true
 
@@ -262,7 +262,7 @@
                                              //type.inferring)]
                               (in (and (type#= :variant:
                                                :it:)
-                                       (case it
+                                       (when it
                                          (//.variant [  ( actual)])
                                          (same?  actual)
 
@@ -293,7 +293,7 @@
                              //type.inferring)]
               (in (and (type#= :either:
                                :it:)
-                       (case it
+                       (when it
                          (//.variant [0 .false (//.unit)])
                          true
 
@@ -323,7 +323,7 @@
                              //type.inferring)]
               (in (and (type#= :either:
                                :it:)
-                       (case it
+                       (when it
                          (//.variant [0 #1 (//.tuple (list (//.unit)
                                                            (//.bit bit/?)
                                                            (//.nat nat/?)
@@ -365,7 +365,7 @@
                          //type.inferring)]
           (in (and (type#= (type_literal [.Any .Bit .Nat .Int .Rev .Frac .Text])
                            :it:)
-                   (case it
+                   (when it
                      (//.tuple (list (//.unit)
                                      (//.bit bit/?)
                                      (//.nat nat/?)
@@ -408,7 +408,7 @@
                          //type.inferring)]
           (in (and (type#= :record:
                            :it:)
-                   (case it
+                   (when it
                      (//.tuple (list (//.unit)
                                      (//.bit bit/?)
                                      (//.nat nat/?)
@@ -443,7 +443,7 @@
                              //type.inferring)]
               (in (and (type#= (All (_ a) (-> a .Nat))
                                :it:)
-                       (case it
+                       (when it
                          {//.#Function (list) (//.nat nat/?)}
                          (same? nat/0 nat/?)
 
@@ -464,7 +464,7 @@
                              //type.inferring)]
               (in (and (type#= (All (_ a) (-> a (All (_ b) (-> b .Nat))))
                                :it:)
-                       (case it
+                       (when it
                          {//.#Function (list) {//.#Function (list) (//.nat nat/?)}}
                          (same? nat/0 nat/?)
 
@@ -485,7 +485,7 @@
                              //type.inferring)]
               (in (and (type#= (All (_ a) (-> a (All (_ b) (-> b b))))
                                :it:)
-                       (case it
+                       (when it
                          {//.#Function (list) {//.#Function (list) (//.local 1)}}
                          true
 
@@ -504,7 +504,7 @@
                                   (, $parameter/0))))
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
-              (in (and (case it
+              (in (and (when it
                          {//.#Function (list) {//.#Function (list (//.local 1)) (//.foreign 0)}}
                          true
 
@@ -530,7 +530,7 @@
          ...                           (, $abstraction/1))))
          ...                      (/.phase ..expander archive.empty)
          ...                      //type.inferring)]
-         ...       (in (case it
+         ...       (in (when it
          ...             {//.#Function (list) {//.#Function (list) (//.local 0)}}
          ...             true
 
@@ -548,7 +548,7 @@
          ...                           (, $abstraction/0))))
          ...                      (/.phase ..expander archive.empty)
          ...                      //type.inferring)]
-         ...       (in (case it
+         ...       (in (when it
          ...             {//.#Function (list) {//.#Function (list (//.local 0)) (//.foreign 0)}}
          ...             true
 
@@ -573,7 +573,7 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (type#= .Bit :it:)
-                       (case it
+                       (when it
                          {//.#Apply (//.nat nat/?)
                                     {//.#Function (list) (//.bit bit/?)}}
                          (and (same? bit/0 bit/?)
@@ -594,7 +594,7 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (type#= .Nat :it:)
-                       (case it
+                       (when it
                          {//.#Apply (//.nat nat/?)
                                     {//.#Function (list) (//.local 1)}}
                          (same? nat/0 nat/?)
@@ -616,7 +616,7 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (check.subsumes? (All (_ a) (-> a Bit)) :it:)
-                       (case it
+                       (when it
                          {//.#Apply (//.nat nat/?)
                                     {//.#Function (list)
                                                   {//.#Function (list) (//.bit bit/?)}}}
@@ -643,7 +643,7 @@
                          (/.phase ..expander archive.empty)
                          //type.inferring)]
           (in (and (type#= .Text :it:)
-                   (case it
+                   (when it
                      {//.#Extension "lux text concat" (list (//.text left) (//.text right))}
                      (and (same? text/0 left)
                           (same? text/0 right))
@@ -676,8 +676,8 @@
                                              (/.phase ..expander archive.empty)
                                              //type.inferring)]
                               (in (and (type#= .Frac :it:)
-                                       (case it
-                                         {//.#Case ( input/?)
+                                       (when it
+                                         {//.#When ( input/?)
                                                    [[//.#when (//pattern.bind 0)
                                                      //.#then (//.frac frac/?)]
                                                     (list)]}
@@ -701,8 +701,8 @@
                                              (/.phase ..expander archive.empty)
                                              //type.inferring)]
                               (in (and (type#= .Frac :it:)
-                                       (case it
-                                         {//.#Case ( input/?)
+                                       (when it
+                                         {//.#When ( input/?)
                                                    [[//.#when ( pattern/?)
                                                      //.#then (//.frac frac/?)]
                                                     (list [//.#when (//pattern.bind 0)
@@ -738,8 +738,8 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (type#= .Frac :it:)
-                       (case it
-                         {//.#Case (//.bit bit/?)
+                       (when it
+                         {//.#When (//.bit bit/?)
                                    [[//.#when (//pattern.bit .false)
                                      //.#then (//.frac false/?)]
                                     (list [//.#when (//pattern.bit .true)
@@ -769,8 +769,8 @@
                                              (/.phase ..expander archive.empty)
                                              //type.inferring)]
                               (in (and (type#= .Frac :it:)
-                                       (case it
-                                         {//.#Case (//.variant [  ( analysis/?)])
+                                       (when it
+                                         {//.#When (//.variant [  ( analysis/?)])
                                                    [[//.#when (//pattern.variant [  ( pattern/?)])
                                                      //.#then (//.frac match/?)]
                                                     (list [//.#when (//pattern.bind 0)
@@ -808,8 +808,8 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (type#= .Frac :it:)
-                       (case it
-                         {//.#Case (//.tuple (list (//.bit bit/?) (//.nat nat/?)))
+                       (when it
+                         {//.#When (//.tuple (list (//.bit bit/?) (//.nat nat/?)))
                                    [[//.#when (//pattern.tuple (list (//pattern.bit .false) (//pattern.bind 0)))
                                      //.#then (//.frac false/?)]
                                     (list [//.#when (//pattern.tuple (list (//pattern.bit .true) (//pattern.bind 0)))
@@ -851,8 +851,8 @@
                              (/.phase ..expander archive.empty)
                              //type.inferring)]
               (in (and (type#= .Frac :it:)
-                       (case it
-                         {//.#Case (//.tuple (list (//.unit)
+                       (when it
+                         {//.#When (//.tuple (list (//.unit)
                                                    (//.bit bit/?)
                                                    (//.nat nat/?)
                                                    (//.int int/?)
@@ -964,5 +964,5 @@
            /complex.test
            /reference.test
            /function.test
-           /case.test
+           /when.test
            )))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/case.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/case.lux
deleted file mode 100644
index 16d10e01a..000000000
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/case.lux
+++ /dev/null
@@ -1,637 +0,0 @@
-(.require
- [library
-  [lux (.except)
-   [abstract
-    [monad (.only do)]]
-   [control
-    ["[0]" try (.only Try) (.use "[1]#[0]" functor)]
-    ["[0]" exception]]
-   [data
-    ["[0]" product]
-    ["[0]" text (.only)
-     ["%" \\format]]]
-   [math
-    ["[0]" random]]
-   [meta
-    ["[0]" code]
-    ["[0]" macro]
-    ["[0]" type (.use "[1]#[0]" equivalence)
-     ["[0]" check]]]
-   [test
-    ["_" property (.only Test)]]]]
- [\\library
-  ["[0]" / (.only)
-   ["/[1]" // (.only)
-    [//
-     ["[1][0]" extension (.only)
-      ["[1]/[0]" analysis
-       ["[1]" lux]]]
-     [//
-      ["[1][0]" analysis (.only)
-       [evaluation (.only Eval)]
-       ["[2][0]" macro]
-       ["[2][0]" scope]
-       ["[2][0]" module]
-       ["[2][0]" coverage]
-       ["[2][0]" type (.only)
-        ["$[1]" \\test]]
-       ["[2][0]" inference
-        ["$[1]" \\test]]]
-      [///
-       ["[1][0]" phase (.use "[1]#[0]" monad)]
-       [meta
-        ["[0]" archive]]]]]]]])
-
-(def (eval archive type term)
-  Eval
-  (//phase#in []))
-
-(def (expander macro inputs state)
-  //macro.Expander
-  {try.#Success ((macro.function macro) inputs state)})
-
-(def analysis
-  //analysis.Phase
-  (//.phase ..expander))
-
-(def test|tuple
-  Test
-  (do [! random.monad]
-    [lux $//type.random_state
-     .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-                  //extension.#state lux]]
-     module/0 (random.lower_case 1)
-     name/0 (at ! each (|>> [module/0]) (random.lower_case 2))
-     [input/0 simple/0] $//inference.simple_parameter
-     [input/1 simple/1] $//inference.simple_parameter
-     [input/2 simple/2] $//inference.simple_parameter
-     $binding/0 (at ! each code.local (random.lower_case 3))
-     $binding/1 (at ! each code.local (random.lower_case 4))
-     $binding/2 (at ! each code.local (random.lower_case 5))]
-    (all _.and
-         (_.coverage [/.tuple]
-           (let [tuple? (is (-> Type Type Bit)
-                            (function (_ :input: :expected:)
-                              (and (|> :input:
-                                       /.tuple
-                                       (check.result check.fresh_context)
-                                       (try#each (|>> product.right (type#= :expected:)))
-                                       (try.else false))
-                                   (|> (do check.monad
-                                         [[@var :var:] check.var
-                                          _ (check.check :var: :input:)]
-                                         (/.tuple :var:))
-                                       (check.result check.fresh_context)
-                                       (try#each (|>> product.right (type#= :expected:)))
-                                       (try.else false)))))]
-             (and (tuple? input/0
-                          (type.anonymous input/0))
-                  (tuple? (Tuple input/0 input/1 input/2)
-                          (Tuple input/0 input/1 input/2))
-                  (tuple? {.#Named name/0 (Tuple input/0 input/1 input/2)}
-                          (Tuple input/0 input/1 input/2))
-                  (tuple? (All (_ a b c) (Tuple input/0 input/1 input/2))
-                          (Tuple (All (_ a b c) input/0)
-                                 (All (_ a b c) input/1)
-                                 (All (_ a b c) input/2)))
-                  (tuple? (type_literal ((All (_ a b c) (Tuple a b c)) input/0 input/1 input/2))
-                          (Tuple input/0 input/1 input/2))
-                  (|> (do check.monad
-                        [[@var :var:] check.var
-                         _ (check.bind (All (_ a b c) (Tuple a b c)) @var)]
-                        (/.tuple (type_literal (:var: input/0 input/1 input/2))))
-                      (check.result check.fresh_context)
-                      (try#each (|>> product.right (type#= (Tuple input/0 input/1 input/2))))
-                      (try.else false))
-                  (|> (do check.monad
-                        [[@0 :0:] check.existential
-                         [@1 :1:] check.existential
-                         [_ :tuple:] (/.tuple (Ex (_ a b c) (Tuple a input/1 c)))
-                         context check.context
-                         _ (check.with context)
-                         _ (check.check (Tuple :0: input/1 :1:) :tuple:)
-                         _ (check.with context)
-                         _ (check.check :tuple: (Tuple :0: input/1 :1:))]
-                        (in true))
-                      (check.result check.fresh_context)
-                      (try.else false)))))
-         (_.coverage [/.non_tuple]
-           (and (|> (do check.monad
-                      [[@var :var:] check.var
-                       _ (/.tuple :var:)]
-                      (in false))
-                    (check.result check.fresh_context)
-                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
-                (|> (do check.monad
-                      [[@var :var:] check.var
-                       _ (/.tuple (type_literal (:var: input/0 input/1 input/2)))]
-                      (in false))
-                    (check.result check.fresh_context)
-                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
-                (|> (do check.monad
-                      [_ (/.tuple (type_literal (input/0 input/1 input/2)))]
-                      (in false))
-                    (check.result check.fresh_context)
-                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
-                (|> (do check.monad
-                      [[@var :var:] check.var
-                       _ (check.bind input/0 @var)
-                       _ (/.tuple (type_literal (:var: input/1 input/2)))]
-                      (in false))
-                    (check.result check.fresh_context)
-                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))))
-         )))
-
-(def (test|case lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
-  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
-  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-               //extension.#state lux]
-        case? (is (-> Code (List [Code Code]) Bit)
-                  (function (_ input branches)
-                    (|> (do //phase.monad
-                          [analysis (|> (/.case ..analysis branches archive.empty input)
-                                        (//type.expecting output/0))]
-                          (in true))
-                        //scope.with
-                        (//module.with 0 module/0)
-                        (//phase#each (|>> product.right product.right))
-                        (//phase.result state)
-                        (try.else false))))
-
-        body_types_mismatch!
-        (and (not (case? (code.bit bit/0) (list [(` #0) body/1]
-                                                [(` #1) body/1])))
-             (not (case? (code.bit bit/0) (list [(` #0) body/0]
-                                                [(` #1) body/1]))))
-
-        input_types_mismatch!
-        (and (not (case? (code.nat nat/0) (list [(` #0) body/0]
-                                                [(` #1) body/0])))
-             (not (case? (code.bit bit/0) (list [(code.nat nat/0) body/0]
-                                                [$binding/0 body/0]))))
-
-        handles_singletons!
-        (and (case? simple/0 (list [(` [(, $binding/0)]) body/0]))
-             (case? simple/0 (list [(` [(, simple/0)]) body/0]
-                                   [(` [(, $binding/0)]) body/0]))
-             (case? (code.bit bit/0) (list [(` [#0]) body/0]
-                                           [(` [#1]) body/0])))
-
-        can_infer_body!
-        (|> (do //phase.monad
-              [[:actual: analysis] (|> (code.bit bit/0)
-                                       (/.case ..analysis
-                                         (list [(` #0) body/0]
-                                               [(` #1) body/0])
-                                         archive.empty)
-                                       //type.inferring)]
-              (in (type#= output/0 :actual:)))
-            //scope.with
-            (//module.with 0 module/0)
-            (//phase#each (|>> product.right product.right))
-            (//phase.result state)
-            (try.else false))
-
-        ensures_consistent_bodies!
-        (|> (do //phase.monad
-              [[:actual: analysis] (|> (code.bit bit/0)
-                                       (/.case ..analysis
-                                         (list [(` #0) body/0]
-                                               [(` #1) body/1])
-                                         archive.empty)
-                                       //type.inferring)]
-              (in false))
-            //scope.with
-            (//module.with 0 module/0)
-            (//phase#each (|>> product.right product.right))
-            (//phase.result state)
-            (try.else true))]
-    (and body_types_mismatch!
-         input_types_mismatch!
-         handles_singletons!
-         can_infer_body!
-         ensures_consistent_bodies!
-
-         (case? (` [])
-                (list [(` []) body/0]))
-         (case? (` [])
-                (list [$binding/0 body/0]))
-
-         (case? (code.bit bit/0) (list [(` #0) body/0]
-                                       [(` #1) body/0]))
-         (case? (code.bit bit/0) (list [(` #1) body/0]
-                                       [(` #0) body/0]))
-
-         (case? simple/0 (list [$binding/0 body/0]))
-         (case? simple/0 (list [simple/0 body/0]
-                               [$binding/0 body/0]))
-         
-         (case? (` [(, simple/0) (, simple/1) (, simple/2)])
-                (list [$binding/0 body/0]))
-         (case? (` [(, simple/0) (, simple/1) (, simple/2)])
-                (list [(` [(, $binding/0) (, $binding/1)]) body/0]))
-         (case? (` [(, simple/0) (, simple/1) (, simple/2)])
-                (list [(` [(, simple/0) (, simple/1) (, simple/2)]) body/0]
-                      ... 000
-                      [(` [(, $binding/0) (, simple/1) (, simple/2)]) body/0]
-                      ... 001
-                      [(` [(, simple/0) (, $binding/1) (, simple/2)]) body/0]
-                      ... 010
-                      [(` [(, $binding/0) (, $binding/1) (, simple/2)]) body/0]
-                      ... 011
-                      [(` [(, simple/0) (, simple/1) (, $binding/2)]) body/0]
-                      ... 100
-                      [(` [(, $binding/0) (, simple/1) (, $binding/2)]) body/0]
-                      ... 101
-                      [(` [(, simple/0) (, $binding/1) (, $binding/2)]) body/0]
-                      ... 110
-                      [(` [(, $binding/0) (, $binding/1) (, $binding/2)]) body/0]
-                      ... 111
-                      )))))
-
-(def (test|redundancy lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] bit/0)
-  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] Bit Bit)
-  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-               //extension.#state lux]
-        redundant? (is (-> Code (List [Code Code]) Bit)
-                       (function (_ input branches)
-                         (|> (do //phase.monad
-                               [analysis (|> (/.case ..analysis branches archive.empty input)
-                                             (//type.expecting output/0))]
-                               (in true))
-                             //scope.with
-                             (//module.with 0 module/0)
-                             (//phase#each (|>> product.right product.right))
-                             (//phase.result state)
-                             (exception.otherwise (text.contains? (the exception.#label //coverage.redundancy))))))]
-    (and (redundant? (` [])
-                     (list [(` []) body/0]
-                           [(` []) body/0]))
-         (redundant? (` [])
-                     (list [$binding/0 body/0]
-                           [$binding/0 body/0]))
-         (redundant? (code.bit bit/0) (list [(` #0) body/0]
-                                            [(` #1) body/0]
-                                            [(` #0) body/0]))
-         (redundant? (code.bit bit/0) (list [(` #0) body/0]
-                                            [(` #1) body/0]
-                                            [(` #1) body/0]))
-         (redundant? (code.bit bit/0) (list [(` #0) body/0]
-                                            [(` #1) body/0]
-                                            [$binding/0 body/0]))
-         (redundant? simple/0 (list [$binding/0 body/0]
-                                    [$binding/0 body/0]))
-         (redundant? simple/0 (list [simple/0 body/0]
-                                    [$binding/0 body/0]
-                                    [$binding/0 body/0]))
-         (redundant? simple/0 (list [$binding/0 body/0]
-                                    [simple/0 body/0]))
-         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
-                     (list [$binding/0 body/0]
-                           [$binding/0 body/0]))
-         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
-                     (list [(` [(, $binding/0) (, $binding/1)]) body/0]
-                           [(` [(, $binding/0) (, $binding/1)]) body/0]))
-         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
-                     (list [(` [(, $binding/0) (, $binding/1)]) body/0]
-                           [$binding/0 body/0]))
-         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
-                     (list [$binding/0 body/0]
-                           [(` [(, $binding/0) (, $binding/1)]) body/0])))))
-
-(def (test|variant lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
-  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
-  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-               //extension.#state lux]
-        
-        tag/0 (%.code $binding/0)
-        tag/1 (%.code $binding/1)
-        tag/2 (%.code $binding/2)
-
-        tags/* (list tag/0 tag/1 tag/2)
-        :variant: {.#Named [module/0 name/0] (type.variant (list input/0 input/1 input/2))}
-
-        tag/0 (code.symbol [module/0 tag/0])
-        tag/1 (code.symbol [module/0 tag/1])
-        tag/2 (code.symbol [module/0 tag/2])
-        
-        variant? (is (-> Code (List [Code Code]) Bit)
-                     (function (_ input branches)
-                       (|> (do //phase.monad
-                             [_ (//module.declare_labels false tags/* false :variant:)
-                              analysis (|> (/.case ..analysis branches archive.empty input)
-                                           (//type.expecting output/0))]
-                             (in true))
-                           //scope.with
-                           (//module.with 0 module/0)
-                           (//phase#each (|>> product.right product.right))
-                           (//phase.result state)
-                           (try.else false))))
-
-        can_bind!
-        (and (variant? (` {(, tag/0) (, simple/0)})
-                       (list [$binding/0 body/0]))
-             (variant? (` {(, tag/1) (, simple/1)})
-                       (list [$binding/0 body/0]))
-             (variant? (` {(, tag/2) (, simple/2)})
-                       (list [$binding/0 body/0])))
-
-        can_bind_variant!
-        (variant? (` {(, tag/0) (, simple/0)})
-                  (list [(` {(, tag/0) (, $binding/0)}) body/0]
-                        [(` {(, tag/1) (, $binding/1)}) body/0]
-                        [(` {(, tag/2) (, $binding/2)}) body/0]))
-
-        can_bind_sum!
-        (variant? (` {(, tag/0) (, simple/0)})
-                  (list [(` {0 #0 (, $binding/0)}) body/0]
-                        [(` {1 #0 (, $binding/1)}) body/0]
-                        [(` {1 #1 (, $binding/2)}) body/0]))
-
-        can_check_exhaustiveness!
-        (variant? (` {(, tag/0) (, simple/0)})
-                  (list [(` {(, tag/0) (, simple/0)}) body/0]
-                        [(` {(, tag/0) (, $binding/0)}) body/0]
-
-                        [(` {(, tag/1) (, simple/1)}) body/0]
-                        [(` {(, tag/1) (, $binding/1)}) body/0]
-
-                        [(` {(, tag/2) (, simple/2)}) body/0]
-                        [(` {(, tag/2) (, $binding/2)}) body/0]))
-
-        can_bind_partial_variant!
-        (variant? (` {(, tag/0) (, simple/0)})
-                  (list [(` {(, tag/0) (, $binding/0)}) body/0]
-                        [(` {0 #1 (, $binding/1)}) body/0]))]
-    (and can_bind!
-         can_bind_variant!
-         can_bind_sum!
-         can_check_exhaustiveness!
-         can_bind_partial_variant!
-         )))
-
-(def (test|record lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
-  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
-  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-               //extension.#state lux]
-        
-        slot/0 (%.code $binding/0)
-        slot/1 (%.code $binding/1)
-        slot/2 (%.code $binding/2)
-
-        slots/* (list slot/0 slot/1 slot/2)
-        :record: {.#Named [module/0 name/0] (type.tuple (list input/0 input/1 input/2))}
-
-        slot/0 (code.symbol [module/0 slot/0])
-        slot/1 (code.symbol [module/0 slot/1])
-        slot/2 (code.symbol [module/0 slot/2])
-        
-        record? (is (-> Code (List [Code Code]) Bit)
-                    (function (_ input branches)
-                      (|> (do //phase.monad
-                            [_ (//module.declare_labels true slots/* false :record:)
-                             analysis (|> (/.case ..analysis branches archive.empty input)
-                                          (//type.expecting output/0))]
-                            (in true))
-                          //scope.with
-                          (//module.with 0 module/0)
-                          (//phase#each (|>> product.right product.right))
-                          (//phase.result state)
-                          (try.else false))))
-
-        can_bind!
-        (record? (` [(, slot/0) (, simple/0)
-                     (, slot/1) (, simple/1)
-                     (, slot/2) (, simple/2)])
-                 (list [$binding/0 body/0]))
-
-        can_bind_record!
-        (record? (` [(, slot/0) (, simple/0)
-                     (, slot/1) (, simple/1)
-                     (, slot/2) (, simple/2)])
-                 (list [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, $binding/2)]) body/0]))
-
-        can_bind_tuple!
-        (record? (` [(, slot/0) (, simple/0)
-                     (, slot/1) (, simple/1)
-                     (, slot/2) (, simple/2)])
-                 (list [(` [(, $binding/0) (, $binding/1) (, $binding/2)]) body/0]))
-
-        can_deduce_record!
-        (record? (` [(, simple/0)
-                     (, simple/1)
-                     (, simple/2)])
-                 (list [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, $binding/2)]) body/0]))
-
-        can_check_exhaustiveness!
-        (record? (` [(, slot/0) (, simple/0)
-                     (, slot/1) (, simple/1)
-                     (, slot/2) (, simple/2)])
-                 (list [(` [(, slot/0) (, simple/0)
-                            (, slot/1) (, simple/1)
-                            (, slot/2) (, simple/2)]) body/0]
-                       ... 000
-                       [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, simple/1)
-                            (, slot/2) (, simple/2)]) body/0]
-                       ... 001
-                       [(` [(, slot/0) (, simple/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, simple/2)]) body/0]
-                       ... 010
-                       [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, simple/2)]) body/0]
-                       ... 011
-                       [(` [(, slot/0) (, simple/0)
-                            (, slot/1) (, simple/1)
-                            (, slot/2) (, $binding/2)]) body/0]
-                       ... 100
-                       [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, simple/1)
-                            (, slot/2) (, $binding/2)]) body/0]
-                       ... 101
-                       [(` [(, slot/0) (, simple/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, $binding/2)]) body/0]
-                       ... 110
-                       [(` [(, slot/0) (, $binding/0)
-                            (, slot/1) (, $binding/1)
-                            (, slot/2) (, $binding/2)]) body/0]
-                       ... 111
-                       ))
-
-        cannot_repeat_slot!
-        (not (record? (` [(, slot/0) (, simple/0)
-                          (, slot/1) (, simple/1)
-                          (, slot/2) (, simple/2)])
-                      (list [(` [(, slot/0) (, $binding/0)
-                                 (, slot/1) (, $binding/1)
-                                 (, slot/2) (, $binding/2)
-                                 (, slot/2) (, $binding/2)]) body/0])))
-
-        cannot_omit_slot!
-        (not (record? (` [(, slot/0) (, simple/0)
-                          (, slot/1) (, simple/1)
-                          (, slot/2) (, simple/2)])
-                      (list [(` [(, slot/0) (, $binding/0)
-                                 (, slot/1) (, $binding/1)]) body/0])))
-
-        can_bind_partial_tuple!
-        (record? (` [(, slot/0) (, simple/0)
-                     (, slot/1) (, simple/1)
-                     (, slot/2) (, simple/2)])
-                 (list [(` [(, $binding/0) (, $binding/1)]) body/0]))]
-    (and can_bind!
-         can_bind_record!
-         can_bind_tuple!
-         can_deduce_record!
-         can_check_exhaustiveness!
-         cannot_repeat_slot!
-         cannot_omit_slot!
-         can_bind_partial_tuple!)))
-
-(def .public test
-  Test
-  (<| (_.covering /._)
-      (do [! random.monad]
-        [lux $//type.random_state
-         .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-                      //extension.#state lux]]
-         module/0 (random.lower_case 1)
-         name/0 (random.lower_case 2)
-         [input/0 simple/0] $//inference.simple_parameter
-         [input/1 simple/1] $//inference.simple_parameter
-         [input/2 simple/2] $//inference.simple_parameter
-         [output/0 body/0] $//inference.simple_parameter
-         [output/1 body/1] (random.only (|>> product.left (same? output/0) not)
-                                        $//inference.simple_parameter)
-         $binding/0 (at ! each code.local (random.lower_case 3))
-         $binding/1 (at ! each code.local (random.lower_case 4))
-         $binding/2 (at ! each code.local (random.lower_case 5))
-         extension/0 (at ! each code.text (random.lower_case 6))
-         bit/0 random.bit
-         nat/0 random.nat]
-        (all _.and
-             (_.coverage [/.case]
-               (and (test|case lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
-                    (test|redundancy lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/1] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [bit/0])
-                    (test|variant lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
-                    (test|record lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])))
-             (_.coverage [/.empty_branches]
-               (|> (do //phase.monad
-                     [analysis (|> (/.case ..analysis (list) archive.empty simple/0)
-                                   (//type.expecting output/0))]
-                     (in false))
-                   //scope.with
-                   (//module.with 0 module/0)
-                   (//phase#each (|>> product.right product.right))
-                   (//phase.result state)
-                   (exception.otherwise (text.contains? (the exception.#label /.empty_branches)))))
-             (_.coverage [/.non_exhaustive]
-               (let [non_exhaustive? (is (-> (List [Code Code]) Bit)
-                                         (function (_ branches)
-                                           (|> (do //phase.monad
-                                                 [analysis (|> (/.case ..analysis branches archive.empty simple/0)
-                                                               (//type.expecting output/0))]
-                                                 (in false))
-                                               //scope.with
-                                               (//module.with 0 module/0)
-                                               (//phase#each (|>> product.right product.right))
-                                               (//phase.result state)
-                                               (exception.otherwise (text.contains? (the exception.#label /.non_exhaustive))))))]
-                 (and (non_exhaustive? (list [simple/0 body/0]))
-                      (not (non_exhaustive? (list [simple/0 body/0]
-                                                  [$binding/0 body/0]))))))
-             (_.coverage [/.invalid]
-               (let [invalid? (is (-> (List [Code Code]) Bit)
-                                  (function (_ branches)
-                                    (|> (do //phase.monad
-                                          [analysis (|> (/.case ..analysis branches archive.empty simple/0)
-                                                        (//type.expecting output/0))]
-                                          (in false))
-                                        //scope.with
-                                        (//module.with 0 module/0)
-                                        (//phase#each (|>> product.right product.right))
-                                        (//phase.result state)
-                                        (exception.otherwise (text.contains? (the exception.#label /.invalid))))))]
-                 (and (invalid? (list [(` ((, extension/0) (, $binding/0) (, $binding/1) (, $binding/2)))
-                                       body/0]))
-                      (invalid? (list [(` {(, extension/0) (, $binding/0) (, $binding/1) (, $binding/2)})
-                                       body/0]))
-                      (invalid? (list [(` {[] (, $binding/0) (, $binding/1) (, $binding/2)})
-                                       body/0])))))
-             (_.coverage [/.sum_has_no_case]
-               (let [tag/0 (%.code $binding/0)
-                     tag/1 (%.code $binding/1)
-                     tag/2 (%.code $binding/2)
-
-                     tags/* (list tag/0 tag/1 tag/2)
-                     :variant: {.#Named [module/0 name/0] (type.variant (list input/0 input/1 input/2))}
-
-                     tag/0 (code.symbol [module/0 tag/0])
-                     tag/1 (code.symbol [module/0 tag/1])
-                     tag/2 (code.symbol [module/0 tag/2])]
-                 (|> (do //phase.monad
-                       [_ (//module.declare_labels false tags/* false :variant:)
-                        analysis (|> (` {(, tag/0) (, simple/0)})
-                                     (/.case ..analysis
-                                       (list [(` {0 #0 (, $binding/0)}) body/0]
-                                             [(` {1 #0 (, $binding/1)}) body/0]
-                                             [(` {2 #0 (, $binding/2)}) body/0]
-                                             [(` {2 #1 (, $binding/2)}) body/0])
-                                       archive.empty)
-                                     (//type.expecting output/0))]
-                       (in false))
-                     //scope.with
-                     (//module.with 0 module/0)
-                     (//phase#each (|>> product.right product.right))
-                     (//phase.result state)
-                     (exception.otherwise (text.contains? (the exception.#label /.sum_has_no_case))))))
-             (_.coverage [/.mismatch]
-               (let [slot/0 (%.code $binding/0)
-                     slot/1 (%.code $binding/1)
-                     slot/2 (%.code $binding/2)
-
-                     slots/* (list slot/0 slot/1 slot/2)
-                     :record: {.#Named [module/0 name/0] (type.tuple (list input/0 input/1 input/2))}
-
-                     slot/0 (code.symbol [module/0 slot/0])
-                     slot/1 (code.symbol [module/0 slot/1])
-                     slot/2 (code.symbol [module/0 slot/2])]
-                 (and (|> (do //phase.monad
-                            [analysis (|> (` (, simple/0))
-                                          (/.case ..analysis
-                                            (list [(` {0 #0 (, $binding/0)}) body/0]
-                                                  [(` {1 #0 (, $binding/1)}) body/0]
-                                                  [(` {1 #1 (, $binding/2)}) body/0])
-                                            archive.empty)
-                                          (//type.expecting output/0))]
-                            (in false))
-                          //scope.with
-                          (//module.with 0 module/0)
-                          (//phase#each (|>> product.right product.right))
-                          (//phase.result state)
-                          (exception.otherwise (text.contains? (the exception.#label /.mismatch))))
-                      (|> (do //phase.monad
-                            [_ (//module.declare_labels true slots/* false :record:)
-                             analysis (|> (` (, simple/0))
-                                          (/.case ..analysis
-                                            (list [(` [(, slot/0) (, $binding/0)
-                                                       (, slot/1) (, $binding/1)
-                                                       (, slot/2) (, $binding/2)]) body/0])
-                                            archive.empty)
-                                          (//type.expecting output/0))]
-                            (in false))
-                          //scope.with
-                          (//module.with 0 module/0)
-                          (//phase#each (|>> product.right product.right))
-                          (//phase.result state)
-                          (exception.otherwise (text.contains? (the exception.#label /.mismatch)))))))
-             
-             ..test|tuple
-             ))))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/complex.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/complex.lux
index 294251023..6586ac1db 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/complex.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/complex.lux
@@ -81,7 +81,7 @@
 
 (def (failure? exception try)
   (All (_ e a) (-> (Exception e) (Try a) Bit))
-  (case try
+  (when try
     {try.#Success _}
     false
     
@@ -105,7 +105,7 @@
 
 (def (analysed? expected actual)
   (-> Code Analysis Bit)
-  (case [expected actual]
+  (when [expected actual]
     [[_ {.#Tuple (list)}] (//analysis.unit)]
     true
 
@@ -150,7 +150,7 @@
                             (|> (do //phase.monad
                                   [analysis (|> (/.sum ..analysis lefts right? archive.empty code)
                                                 (//type.expecting type))]
-                                  (in (case analysis
+                                  (in (when analysis
                                         (//analysis.variant [lefts' right?' analysis])
                                         (and (n.= lefts lefts')
                                              (bit#= right? right?')
@@ -169,7 +169,7 @@
                          _ (//type.check (check.check varT variantT))
                          analysis (|> (/.sum ..analysis lefts right? archive.empty tagC)
                                       (//type.expecting varT))]
-                        (in (case analysis
+                        (in (when analysis
                               (//analysis.variant [lefts' right?' it])
                               (and (n.= lefts lefts')
                                    (bit#= right? right?')
@@ -242,7 +242,7 @@
                                                [_ (//module.declare_labels false tags false variantT)
                                                 analysis (|> (/.variant ..analysis tag archive.empty tagC)
                                                              (//type.expecting variantT))]
-                                               (in (case analysis
+                                               (in (when analysis
                                                      (//analysis.variant [lefts' right?' analysis])
                                                      (and (n.= lefts lefts')
                                                           (bit#= right? right?')
@@ -260,7 +260,7 @@
                                                [_ (//module.declare_labels false tags false variantT)
                                                 [actualT analysis] (|> (/.variant ..analysis tag archive.empty tagC)
                                                                        //type.inferring)]
-                                               (in (case analysis
+                                               (in (when analysis
                                                      (//analysis.variant [lefts' right?' analysis])
                                                      (and (n.= lefts lefts')
                                                           (bit#= right? right?')
@@ -307,7 +307,7 @@
                                       [analysis (|> expected
                                                     (/.product ..analysis archive.empty)
                                                     (//type.expecting type))]
-                                      (in (case analysis
+                                      (in (when analysis
                                             (//analysis.tuple actual)
                                             (and (n.= (list.size expected)
                                                       (list.size actual))
@@ -332,7 +332,7 @@
                          analysis (|> expected
                                       (/.product ..analysis archive.empty)
                                       (//type.expecting varT))]
-                        (in (case analysis
+                        (in (when analysis
                               (//analysis.tuple actual)
                               (and (n.= (list.size expected)
                                         (list.size actual))
@@ -350,7 +350,7 @@
                         [[:inferred: analysis] (|> expected
                                                    (/.product ..analysis archive.empty)
                                                    //type.inferring)]
-                        (in (case analysis
+                        (in (when analysis
                               (//analysis.tuple actual)
                               (and (n.= (list.size expected)
                                         (list.size actual))
@@ -373,7 +373,7 @@
                                                   (/.product ..analysis archive.empty
                                                              (list term/0 term/1 term/2 term/2 term/2))))
                          :inferred: (//type.check (check.clean (list @var) :inferred:))]
-                        (in (case analysis
+                        (in (when analysis
                               (//analysis.tuple (list analysis/0 analysis/1 (//analysis.tuple (list analysis/2 analysis/3 analysis/4))))
                               (and (type#= (Tuple type/0 type/1 type/2 type/2 type/2)
                                            :inferred:)
@@ -393,7 +393,7 @@
                         [analysis (|> (list term/0 term/1 (code.tuple (list term/2 term/2 term/2)))
                                       (/.product ..analysis archive.empty)
                                       (//type.expecting (Tuple type/0 type/1 type/2 type/2 type/2)))]
-                        (in (case analysis
+                        (in (when analysis
                               (//analysis.tuple (list analysis/0 analysis/1 (//analysis.tuple (list analysis/2 analysis/3 analysis/4))))
                               (and (..analysed? term/0 analysis/0)
                                    (..analysed? term/1 analysis/1)
@@ -465,7 +465,7 @@
            head_slot/0 (|> slots/0 list.head maybe.trusted)
            head_term/0 (|> types/*,terms/* list.head maybe.trusted product.right)
            head_slot/1 (|> slots/1 list.head maybe.trusted)
-           slots/01 (case slots/1
+           slots/01 (when slots/1
                       {.#Item _ tail}
                       {.#Item head_slot/0 tail}
 
@@ -481,7 +481,7 @@
                                    (//module.with 0 module)
                                    (//phase#each product.right)
                                    (//phase.result state)
-                                   (pipe.case
+                                   (pipe.when
                                      {try.#Success {.#Some actual}}
                                      (let [(open "list#[0]") (list.equivalence (product.equivalence symbol.equivalence code.equivalence))]
                                        (list#= expected (list.reversed actual)))
@@ -493,7 +493,7 @@
                   (normal? expected_record local_record)
                   (|> (/.normal false tuple)
                       (//phase.result state)
-                      (pipe.case
+                      (pipe.when
                         {try.#Success {.#None}}
                         true
                         
@@ -511,7 +511,7 @@
                                     (//module.with 0 module)
                                     (//phase#each (|>> product.right product.right))
                                     (//phase.result state)
-                                    (pipe.case
+                                    (pipe.when
                                       {try.#Success {.#Some [actual_arity actual_tuple actual_type]}}
                                       (and (n.= arity actual_arity)
                                            (at code.equivalence = (code.tuple tuple) (code.tuple actual_tuple))
@@ -523,7 +523,7 @@
                            (function (_ pattern_matching?)
                              (|> (/.order false (list))
                                  (//phase.result state)
-                                 (pipe.case
+                                 (pipe.when
                                    {try.#Success {.#Some [0 (list) actual_type]}}
                                    (same? .Any actual_type)
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/function.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/function.lux
index 41d0ff3f1..ad9af9331 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/function.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/function.lux
@@ -89,7 +89,7 @@
                                         [analysis (|> (/.function ..analysis function/0 argument/0 archive.empty
                                                         output_term)
                                                       (//type.expecting function_type))]
-                                        (in (case analysis
+                                        (in (when analysis
                                               {//analysis.#Function it}
                                               (? it)
 
@@ -108,7 +108,7 @@
                                         [[:actual: analysis] (|> (/.function ..analysis function/0 argument/0 archive.empty
                                                                    term)
                                                                  //type.inferring)]
-                                        (in (case analysis
+                                        (in (when analysis
                                               {//analysis.#Function [actual_env actual_body]}
                                               (type#= :expected: :actual:)
 
@@ -138,7 +138,7 @@
                   (function?' (-> input/0 input/1 input/0) (` ([(, $function/1) (, $argument/1)] (, $argument/0)))
                               (function (_ [outer body])
                                 (and (list.empty? outer)
-                                     (case body
+                                     (when body
                                        {//analysis.#Function [inner body]}
                                        (n.= 1 (list.size inner))
 
@@ -147,7 +147,7 @@
                   (function?' (-> input/0 input/1 input/1) (` ([(, $function/1) (, $argument/1)] (, $argument/1)))
                               (function (_ [outer body])
                                 (and (list.empty? outer)
-                                     (case body
+                                     (when body
                                        {//analysis.#Function [inner body]}
                                        (n.= 0 (list.size inner))
 
@@ -160,7 +160,7 @@
                          analysis (|> (/.function ..analysis function/0 argument/0 archive.empty
                                         term/0)
                                       (//type.expecting :var:))]
-                        (in (case analysis
+                        (in (when analysis
                               {//analysis.#Function [actual_env actual_body]}
                               true
 
@@ -182,7 +182,7 @@
                  [analysis (|> (/.function ..analysis function/0 argument/0 archive.empty
                                  term/1)
                                (//type.expecting (-> input/0 output/0)))]
-                 (in (case analysis
+                 (in (when analysis
                        {//analysis.#Function [actual_env actual_body]}
                        true
 
@@ -217,7 +217,7 @@
                                                                             (' []))
                                                                    //type.inferring)]
                                           (in (and (check.subsumes? :expected: :actual:)
-                                                   (case analysis
+                                                   (when analysis
                                                      {//analysis.#Apply _}
                                                      true
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/reference.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/reference.lux
index 060f7cbd1..613cfb643 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/reference.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/reference.lux
@@ -55,7 +55,7 @@
                          (//phase#each product.right)
                          (//phase.result state)
                          (try#each (|>> product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.local 0)]
                                           (type#= expected_type actual_type)
 
@@ -74,7 +74,7 @@
                          (//phase.result state)
                          (try#each (|>> product.right
                                         product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.foreign 0)]
                                           (type#= expected_type actual_type)
 
@@ -90,7 +90,7 @@
                          (//module.with 0 expected_module)
                          (//phase.result state)
                          (try#each (|>> product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.constant [actual_module actual_name])]
                                           (and (type#= expected_type actual_type)
                                                (same? expected_module actual_module)
@@ -110,7 +110,7 @@
                          (//module.with 0 expected_module)
                          (//phase.result state)
                          (try#each (|>> product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.constant [actual_module actual_name])]
                                           (and (type#= expected_type actual_type)
                                                (same? import actual_module)
@@ -131,7 +131,7 @@
                          (//module.with 0 expected_module)
                          (//phase.result state)
                          (try#each (|>> product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.constant [actual_module actual_name])]
                                           (and (type#= expected_type actual_type)
                                                (same? import actual_module)
@@ -152,7 +152,7 @@
                          (//module.with 0 expected_module)
                          (//phase.result state)
                          (try#each (|>> product.right
-                                        (pipe.case
+                                        (pipe.when
                                           [actual_type (//analysis.constant [actual_module actual_name])]
                                           (and (type#= .Type actual_type)
                                                (same? expected_module actual_module)
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/simple.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/simple.lux
index d4b76212d..f8adedaa1 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/simple.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/simple.lux
@@ -35,7 +35,7 @@
            (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
-           (pipe.case
+           (pipe.when
              {try.#Success analysis}
              (? analysis)
 
@@ -47,7 +47,7 @@
            (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
-           (pipe.case
+           (pipe.when
              {try.#Failure error}
              true
 
@@ -59,7 +59,7 @@
            (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
-           (pipe.case
+           (pipe.when
              {try.#Success [inferred analysis]}
              (and (type#= type inferred)
                   (? analysis))
@@ -71,7 +71,7 @@
   (template (_  )
     [(is (->  Analysis Bit)
          (function (_ expected)
-           (|>> (pipe.case
+           (|>> (pipe.when
                   ( actual)
                   (same? expected actual)
 
@@ -89,7 +89,7 @@
         (`` (all _.and
                  (_.coverage [/.unit]
                    (..analysis state module .Any /.unit
-                     (|>> (pipe.case
+                     (|>> (pipe.when
                             (/analysis.unit)
                             true
                             
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/when.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/when.lux
new file mode 100644
index 000000000..03b491fa7
--- /dev/null
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/analysis/when.lux
@@ -0,0 +1,637 @@
+(.require
+ [library
+  [lux (.except)
+   [abstract
+    [monad (.only do)]]
+   [control
+    ["[0]" try (.only Try) (.use "[1]#[0]" functor)]
+    ["[0]" exception]]
+   [data
+    ["[0]" product]
+    ["[0]" text (.only)
+     ["%" \\format]]]
+   [math
+    ["[0]" random]]
+   [meta
+    ["[0]" code]
+    ["[0]" macro]
+    ["[0]" type (.use "[1]#[0]" equivalence)
+     ["[0]" check]]]
+   [test
+    ["_" property (.only Test)]]]]
+ [\\library
+  ["[0]" / (.only)
+   ["/[1]" // (.only)
+    [//
+     ["[1][0]" extension (.only)
+      ["[1]/[0]" analysis
+       ["[1]" lux]]]
+     [//
+      ["[1][0]" analysis (.only)
+       [evaluation (.only Eval)]
+       ["[2][0]" macro]
+       ["[2][0]" scope]
+       ["[2][0]" module]
+       ["[2][0]" coverage]
+       ["[2][0]" type (.only)
+        ["$[1]" \\test]]
+       ["[2][0]" inference
+        ["$[1]" \\test]]]
+      [///
+       ["[1][0]" phase (.use "[1]#[0]" monad)]
+       [meta
+        ["[0]" archive]]]]]]]])
+
+(def (eval archive type term)
+  Eval
+  (//phase#in []))
+
+(def (expander macro inputs state)
+  //macro.Expander
+  {try.#Success ((macro.function macro) inputs state)})
+
+(def analysis
+  //analysis.Phase
+  (//.phase ..expander))
+
+(def test|tuple
+  Test
+  (do [! random.monad]
+    [lux $//type.random_state
+     .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+                  //extension.#state lux]]
+     module/0 (random.lower_case 1)
+     name/0 (at ! each (|>> [module/0]) (random.lower_case 2))
+     [input/0 simple/0] $//inference.simple_parameter
+     [input/1 simple/1] $//inference.simple_parameter
+     [input/2 simple/2] $//inference.simple_parameter
+     $binding/0 (at ! each code.local (random.lower_case 3))
+     $binding/1 (at ! each code.local (random.lower_case 4))
+     $binding/2 (at ! each code.local (random.lower_case 5))]
+    (all _.and
+         (_.coverage [/.tuple]
+           (let [tuple? (is (-> Type Type Bit)
+                            (function (_ :input: :expected:)
+                              (and (|> :input:
+                                       /.tuple
+                                       (check.result check.fresh_context)
+                                       (try#each (|>> product.right (type#= :expected:)))
+                                       (try.else false))
+                                   (|> (do check.monad
+                                         [[@var :var:] check.var
+                                          _ (check.check :var: :input:)]
+                                         (/.tuple :var:))
+                                       (check.result check.fresh_context)
+                                       (try#each (|>> product.right (type#= :expected:)))
+                                       (try.else false)))))]
+             (and (tuple? input/0
+                          (type.anonymous input/0))
+                  (tuple? (Tuple input/0 input/1 input/2)
+                          (Tuple input/0 input/1 input/2))
+                  (tuple? {.#Named name/0 (Tuple input/0 input/1 input/2)}
+                          (Tuple input/0 input/1 input/2))
+                  (tuple? (All (_ a b c) (Tuple input/0 input/1 input/2))
+                          (Tuple (All (_ a b c) input/0)
+                                 (All (_ a b c) input/1)
+                                 (All (_ a b c) input/2)))
+                  (tuple? (type_literal ((All (_ a b c) (Tuple a b c)) input/0 input/1 input/2))
+                          (Tuple input/0 input/1 input/2))
+                  (|> (do check.monad
+                        [[@var :var:] check.var
+                         _ (check.bind (All (_ a b c) (Tuple a b c)) @var)]
+                        (/.tuple (type_literal (:var: input/0 input/1 input/2))))
+                      (check.result check.fresh_context)
+                      (try#each (|>> product.right (type#= (Tuple input/0 input/1 input/2))))
+                      (try.else false))
+                  (|> (do check.monad
+                        [[@0 :0:] check.existential
+                         [@1 :1:] check.existential
+                         [_ :tuple:] (/.tuple (Ex (_ a b c) (Tuple a input/1 c)))
+                         context check.context
+                         _ (check.with context)
+                         _ (check.check (Tuple :0: input/1 :1:) :tuple:)
+                         _ (check.with context)
+                         _ (check.check :tuple: (Tuple :0: input/1 :1:))]
+                        (in true))
+                      (check.result check.fresh_context)
+                      (try.else false)))))
+         (_.coverage [/.non_tuple]
+           (and (|> (do check.monad
+                      [[@var :var:] check.var
+                       _ (/.tuple :var:)]
+                      (in false))
+                    (check.result check.fresh_context)
+                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
+                (|> (do check.monad
+                      [[@var :var:] check.var
+                       _ (/.tuple (type_literal (:var: input/0 input/1 input/2)))]
+                      (in false))
+                    (check.result check.fresh_context)
+                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
+                (|> (do check.monad
+                      [_ (/.tuple (type_literal (input/0 input/1 input/2)))]
+                      (in false))
+                    (check.result check.fresh_context)
+                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))
+                (|> (do check.monad
+                      [[@var :var:] check.var
+                       _ (check.bind input/0 @var)
+                       _ (/.tuple (type_literal (:var: input/1 input/2)))]
+                      (in false))
+                    (check.result check.fresh_context)
+                    (exception.otherwise (text.contains? (the exception.#label /.non_tuple))))))
+         )))
+
+(def (test|when lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
+  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
+  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+               //extension.#state lux]
+        when? (is (-> Code (List [Code Code]) Bit)
+                  (function (_ input branches)
+                    (|> (do //phase.monad
+                          [analysis (|> (/.when ..analysis branches archive.empty input)
+                                        (//type.expecting output/0))]
+                          (in true))
+                        //scope.with
+                        (//module.with 0 module/0)
+                        (//phase#each (|>> product.right product.right))
+                        (//phase.result state)
+                        (try.else false))))
+
+        body_types_mismatch!
+        (and (not (when? (code.bit bit/0) (list [(` #0) body/1]
+                                                [(` #1) body/1])))
+             (not (when? (code.bit bit/0) (list [(` #0) body/0]
+                                                [(` #1) body/1]))))
+
+        input_types_mismatch!
+        (and (not (when? (code.nat nat/0) (list [(` #0) body/0]
+                                                [(` #1) body/0])))
+             (not (when? (code.bit bit/0) (list [(code.nat nat/0) body/0]
+                                                [$binding/0 body/0]))))
+
+        handles_singletons!
+        (and (when? simple/0 (list [(` [(, $binding/0)]) body/0]))
+             (when? simple/0 (list [(` [(, simple/0)]) body/0]
+                                   [(` [(, $binding/0)]) body/0]))
+             (when? (code.bit bit/0) (list [(` [#0]) body/0]
+                                           [(` [#1]) body/0])))
+
+        can_infer_body!
+        (|> (do //phase.monad
+              [[:actual: analysis] (|> (code.bit bit/0)
+                                       (/.when ..analysis
+                                         (list [(` #0) body/0]
+                                               [(` #1) body/0])
+                                         archive.empty)
+                                       //type.inferring)]
+              (in (type#= output/0 :actual:)))
+            //scope.with
+            (//module.with 0 module/0)
+            (//phase#each (|>> product.right product.right))
+            (//phase.result state)
+            (try.else false))
+
+        ensures_consistent_bodies!
+        (|> (do //phase.monad
+              [[:actual: analysis] (|> (code.bit bit/0)
+                                       (/.when ..analysis
+                                         (list [(` #0) body/0]
+                                               [(` #1) body/1])
+                                         archive.empty)
+                                       //type.inferring)]
+              (in false))
+            //scope.with
+            (//module.with 0 module/0)
+            (//phase#each (|>> product.right product.right))
+            (//phase.result state)
+            (try.else true))]
+    (and body_types_mismatch!
+         input_types_mismatch!
+         handles_singletons!
+         can_infer_body!
+         ensures_consistent_bodies!
+
+         (when? (` [])
+                (list [(` []) body/0]))
+         (when? (` [])
+                (list [$binding/0 body/0]))
+
+         (when? (code.bit bit/0) (list [(` #0) body/0]
+                                       [(` #1) body/0]))
+         (when? (code.bit bit/0) (list [(` #1) body/0]
+                                       [(` #0) body/0]))
+
+         (when? simple/0 (list [$binding/0 body/0]))
+         (when? simple/0 (list [simple/0 body/0]
+                               [$binding/0 body/0]))
+         
+         (when? (` [(, simple/0) (, simple/1) (, simple/2)])
+                (list [$binding/0 body/0]))
+         (when? (` [(, simple/0) (, simple/1) (, simple/2)])
+                (list [(` [(, $binding/0) (, $binding/1)]) body/0]))
+         (when? (` [(, simple/0) (, simple/1) (, simple/2)])
+                (list [(` [(, simple/0) (, simple/1) (, simple/2)]) body/0]
+                      ... 000
+                      [(` [(, $binding/0) (, simple/1) (, simple/2)]) body/0]
+                      ... 001
+                      [(` [(, simple/0) (, $binding/1) (, simple/2)]) body/0]
+                      ... 010
+                      [(` [(, $binding/0) (, $binding/1) (, simple/2)]) body/0]
+                      ... 011
+                      [(` [(, simple/0) (, simple/1) (, $binding/2)]) body/0]
+                      ... 100
+                      [(` [(, $binding/0) (, simple/1) (, $binding/2)]) body/0]
+                      ... 101
+                      [(` [(, simple/0) (, $binding/1) (, $binding/2)]) body/0]
+                      ... 110
+                      [(` [(, $binding/0) (, $binding/1) (, $binding/2)]) body/0]
+                      ... 111
+                      )))))
+
+(def (test|redundancy lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] bit/0)
+  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] Bit Bit)
+  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+               //extension.#state lux]
+        redundant? (is (-> Code (List [Code Code]) Bit)
+                       (function (_ input branches)
+                         (|> (do //phase.monad
+                               [analysis (|> (/.when ..analysis branches archive.empty input)
+                                             (//type.expecting output/0))]
+                               (in true))
+                             //scope.with
+                             (//module.with 0 module/0)
+                             (//phase#each (|>> product.right product.right))
+                             (//phase.result state)
+                             (exception.otherwise (text.contains? (the exception.#label //coverage.redundancy))))))]
+    (and (redundant? (` [])
+                     (list [(` []) body/0]
+                           [(` []) body/0]))
+         (redundant? (` [])
+                     (list [$binding/0 body/0]
+                           [$binding/0 body/0]))
+         (redundant? (code.bit bit/0) (list [(` #0) body/0]
+                                            [(` #1) body/0]
+                                            [(` #0) body/0]))
+         (redundant? (code.bit bit/0) (list [(` #0) body/0]
+                                            [(` #1) body/0]
+                                            [(` #1) body/0]))
+         (redundant? (code.bit bit/0) (list [(` #0) body/0]
+                                            [(` #1) body/0]
+                                            [$binding/0 body/0]))
+         (redundant? simple/0 (list [$binding/0 body/0]
+                                    [$binding/0 body/0]))
+         (redundant? simple/0 (list [simple/0 body/0]
+                                    [$binding/0 body/0]
+                                    [$binding/0 body/0]))
+         (redundant? simple/0 (list [$binding/0 body/0]
+                                    [simple/0 body/0]))
+         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
+                     (list [$binding/0 body/0]
+                           [$binding/0 body/0]))
+         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
+                     (list [(` [(, $binding/0) (, $binding/1)]) body/0]
+                           [(` [(, $binding/0) (, $binding/1)]) body/0]))
+         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
+                     (list [(` [(, $binding/0) (, $binding/1)]) body/0]
+                           [$binding/0 body/0]))
+         (redundant? (` [(, simple/0) (, simple/1) (, simple/2)])
+                     (list [$binding/0 body/0]
+                           [(` [(, $binding/0) (, $binding/1)]) body/0])))))
+
+(def (test|variant lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
+  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
+  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+               //extension.#state lux]
+        
+        tag/0 (%.code $binding/0)
+        tag/1 (%.code $binding/1)
+        tag/2 (%.code $binding/2)
+
+        tags/* (list tag/0 tag/1 tag/2)
+        :variant: {.#Named [module/0 name/0] (type.variant (list input/0 input/1 input/2))}
+
+        tag/0 (code.symbol [module/0 tag/0])
+        tag/1 (code.symbol [module/0 tag/1])
+        tag/2 (code.symbol [module/0 tag/2])
+        
+        variant? (is (-> Code (List [Code Code]) Bit)
+                     (function (_ input branches)
+                       (|> (do //phase.monad
+                             [_ (//module.declare_labels false tags/* false :variant:)
+                              analysis (|> (/.when ..analysis branches archive.empty input)
+                                           (//type.expecting output/0))]
+                             (in true))
+                           //scope.with
+                           (//module.with 0 module/0)
+                           (//phase#each (|>> product.right product.right))
+                           (//phase.result state)
+                           (try.else false))))
+
+        can_bind!
+        (and (variant? (` {(, tag/0) (, simple/0)})
+                       (list [$binding/0 body/0]))
+             (variant? (` {(, tag/1) (, simple/1)})
+                       (list [$binding/0 body/0]))
+             (variant? (` {(, tag/2) (, simple/2)})
+                       (list [$binding/0 body/0])))
+
+        can_bind_variant!
+        (variant? (` {(, tag/0) (, simple/0)})
+                  (list [(` {(, tag/0) (, $binding/0)}) body/0]
+                        [(` {(, tag/1) (, $binding/1)}) body/0]
+                        [(` {(, tag/2) (, $binding/2)}) body/0]))
+
+        can_bind_sum!
+        (variant? (` {(, tag/0) (, simple/0)})
+                  (list [(` {0 #0 (, $binding/0)}) body/0]
+                        [(` {1 #0 (, $binding/1)}) body/0]
+                        [(` {1 #1 (, $binding/2)}) body/0]))
+
+        can_check_exhaustiveness!
+        (variant? (` {(, tag/0) (, simple/0)})
+                  (list [(` {(, tag/0) (, simple/0)}) body/0]
+                        [(` {(, tag/0) (, $binding/0)}) body/0]
+
+                        [(` {(, tag/1) (, simple/1)}) body/0]
+                        [(` {(, tag/1) (, $binding/1)}) body/0]
+
+                        [(` {(, tag/2) (, simple/2)}) body/0]
+                        [(` {(, tag/2) (, $binding/2)}) body/0]))
+
+        can_bind_partial_variant!
+        (variant? (` {(, tag/0) (, simple/0)})
+                  (list [(` {(, tag/0) (, $binding/0)}) body/0]
+                        [(` {0 #1 (, $binding/1)}) body/0]))]
+    (and can_bind!
+         can_bind_variant!
+         can_bind_sum!
+         can_check_exhaustiveness!
+         can_bind_partial_variant!
+         )))
+
+(def (test|record lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
+  (-> Lux Symbol [Type Code] [Type Code] [Type Code] [Code Code Code] [Type Code] [Type Code] [Bit Nat] Bit)
+  (let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+               //extension.#state lux]
+        
+        slot/0 (%.code $binding/0)
+        slot/1 (%.code $binding/1)
+        slot/2 (%.code $binding/2)
+
+        slots/* (list slot/0 slot/1 slot/2)
+        :record: {.#Named [module/0 name/0] (type.tuple (list input/0 input/1 input/2))}
+
+        slot/0 (code.symbol [module/0 slot/0])
+        slot/1 (code.symbol [module/0 slot/1])
+        slot/2 (code.symbol [module/0 slot/2])
+        
+        record? (is (-> Code (List [Code Code]) Bit)
+                    (function (_ input branches)
+                      (|> (do //phase.monad
+                            [_ (//module.declare_labels true slots/* false :record:)
+                             analysis (|> (/.when ..analysis branches archive.empty input)
+                                          (//type.expecting output/0))]
+                            (in true))
+                          //scope.with
+                          (//module.with 0 module/0)
+                          (//phase#each (|>> product.right product.right))
+                          (//phase.result state)
+                          (try.else false))))
+
+        can_bind!
+        (record? (` [(, slot/0) (, simple/0)
+                     (, slot/1) (, simple/1)
+                     (, slot/2) (, simple/2)])
+                 (list [$binding/0 body/0]))
+
+        can_bind_record!
+        (record? (` [(, slot/0) (, simple/0)
+                     (, slot/1) (, simple/1)
+                     (, slot/2) (, simple/2)])
+                 (list [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, $binding/2)]) body/0]))
+
+        can_bind_tuple!
+        (record? (` [(, slot/0) (, simple/0)
+                     (, slot/1) (, simple/1)
+                     (, slot/2) (, simple/2)])
+                 (list [(` [(, $binding/0) (, $binding/1) (, $binding/2)]) body/0]))
+
+        can_deduce_record!
+        (record? (` [(, simple/0)
+                     (, simple/1)
+                     (, simple/2)])
+                 (list [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, $binding/2)]) body/0]))
+
+        can_check_exhaustiveness!
+        (record? (` [(, slot/0) (, simple/0)
+                     (, slot/1) (, simple/1)
+                     (, slot/2) (, simple/2)])
+                 (list [(` [(, slot/0) (, simple/0)
+                            (, slot/1) (, simple/1)
+                            (, slot/2) (, simple/2)]) body/0]
+                       ... 000
+                       [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, simple/1)
+                            (, slot/2) (, simple/2)]) body/0]
+                       ... 001
+                       [(` [(, slot/0) (, simple/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, simple/2)]) body/0]
+                       ... 010
+                       [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, simple/2)]) body/0]
+                       ... 011
+                       [(` [(, slot/0) (, simple/0)
+                            (, slot/1) (, simple/1)
+                            (, slot/2) (, $binding/2)]) body/0]
+                       ... 100
+                       [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, simple/1)
+                            (, slot/2) (, $binding/2)]) body/0]
+                       ... 101
+                       [(` [(, slot/0) (, simple/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, $binding/2)]) body/0]
+                       ... 110
+                       [(` [(, slot/0) (, $binding/0)
+                            (, slot/1) (, $binding/1)
+                            (, slot/2) (, $binding/2)]) body/0]
+                       ... 111
+                       ))
+
+        cannot_repeat_slot!
+        (not (record? (` [(, slot/0) (, simple/0)
+                          (, slot/1) (, simple/1)
+                          (, slot/2) (, simple/2)])
+                      (list [(` [(, slot/0) (, $binding/0)
+                                 (, slot/1) (, $binding/1)
+                                 (, slot/2) (, $binding/2)
+                                 (, slot/2) (, $binding/2)]) body/0])))
+
+        cannot_omit_slot!
+        (not (record? (` [(, slot/0) (, simple/0)
+                          (, slot/1) (, simple/1)
+                          (, slot/2) (, simple/2)])
+                      (list [(` [(, slot/0) (, $binding/0)
+                                 (, slot/1) (, $binding/1)]) body/0])))
+
+        can_bind_partial_tuple!
+        (record? (` [(, slot/0) (, simple/0)
+                     (, slot/1) (, simple/1)
+                     (, slot/2) (, simple/2)])
+                 (list [(` [(, $binding/0) (, $binding/1)]) body/0]))]
+    (and can_bind!
+         can_bind_record!
+         can_bind_tuple!
+         can_deduce_record!
+         can_check_exhaustiveness!
+         cannot_repeat_slot!
+         cannot_omit_slot!
+         can_bind_partial_tuple!)))
+
+(def .public test
+  Test
+  (<| (_.covering /._)
+      (do [! random.monad]
+        [lux $//type.random_state
+         .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+                      //extension.#state lux]]
+         module/0 (random.lower_case 1)
+         name/0 (random.lower_case 2)
+         [input/0 simple/0] $//inference.simple_parameter
+         [input/1 simple/1] $//inference.simple_parameter
+         [input/2 simple/2] $//inference.simple_parameter
+         [output/0 body/0] $//inference.simple_parameter
+         [output/1 body/1] (random.only (|>> product.left (same? output/0) not)
+                                        $//inference.simple_parameter)
+         $binding/0 (at ! each code.local (random.lower_case 3))
+         $binding/1 (at ! each code.local (random.lower_case 4))
+         $binding/2 (at ! each code.local (random.lower_case 5))
+         extension/0 (at ! each code.text (random.lower_case 6))
+         bit/0 random.bit
+         nat/0 random.nat]
+        (all _.and
+             (_.coverage [/.when]
+               (and (test|when lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
+                    (test|redundancy lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/1] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [bit/0])
+                    (test|variant lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])
+                    (test|record lux [module/0 name/0] [input/0 simple/0] [input/1 simple/1] [input/2 simple/2] [$binding/0 $binding/1 $binding/2] [output/0 body/0] [output/1 body/1] [bit/0 nat/0])))
+             (_.coverage [/.empty_branches]
+               (|> (do //phase.monad
+                     [analysis (|> (/.when ..analysis (list) archive.empty simple/0)
+                                   (//type.expecting output/0))]
+                     (in false))
+                   //scope.with
+                   (//module.with 0 module/0)
+                   (//phase#each (|>> product.right product.right))
+                   (//phase.result state)
+                   (exception.otherwise (text.contains? (the exception.#label /.empty_branches)))))
+             (_.coverage [/.non_exhaustive]
+               (let [non_exhaustive? (is (-> (List [Code Code]) Bit)
+                                         (function (_ branches)
+                                           (|> (do //phase.monad
+                                                 [analysis (|> (/.when ..analysis branches archive.empty simple/0)
+                                                               (//type.expecting output/0))]
+                                                 (in false))
+                                               //scope.with
+                                               (//module.with 0 module/0)
+                                               (//phase#each (|>> product.right product.right))
+                                               (//phase.result state)
+                                               (exception.otherwise (text.contains? (the exception.#label /.non_exhaustive))))))]
+                 (and (non_exhaustive? (list [simple/0 body/0]))
+                      (not (non_exhaustive? (list [simple/0 body/0]
+                                                  [$binding/0 body/0]))))))
+             (_.coverage [/.invalid]
+               (let [invalid? (is (-> (List [Code Code]) Bit)
+                                  (function (_ branches)
+                                    (|> (do //phase.monad
+                                          [analysis (|> (/.when ..analysis branches archive.empty simple/0)
+                                                        (//type.expecting output/0))]
+                                          (in false))
+                                        //scope.with
+                                        (//module.with 0 module/0)
+                                        (//phase#each (|>> product.right product.right))
+                                        (//phase.result state)
+                                        (exception.otherwise (text.contains? (the exception.#label /.invalid))))))]
+                 (and (invalid? (list [(` ((, extension/0) (, $binding/0) (, $binding/1) (, $binding/2)))
+                                       body/0]))
+                      (invalid? (list [(` {(, extension/0) (, $binding/0) (, $binding/1) (, $binding/2)})
+                                       body/0]))
+                      (invalid? (list [(` {[] (, $binding/0) (, $binding/1) (, $binding/2)})
+                                       body/0])))))
+             (_.coverage [/.sum_has_no_case]
+               (let [tag/0 (%.code $binding/0)
+                     tag/1 (%.code $binding/1)
+                     tag/2 (%.code $binding/2)
+
+                     tags/* (list tag/0 tag/1 tag/2)
+                     :variant: {.#Named [module/0 name/0] (type.variant (list input/0 input/1 input/2))}
+
+                     tag/0 (code.symbol [module/0 tag/0])
+                     tag/1 (code.symbol [module/0 tag/1])
+                     tag/2 (code.symbol [module/0 tag/2])]
+                 (|> (do //phase.monad
+                       [_ (//module.declare_labels false tags/* false :variant:)
+                        analysis (|> (` {(, tag/0) (, simple/0)})
+                                     (/.when ..analysis
+                                       (list [(` {0 #0 (, $binding/0)}) body/0]
+                                             [(` {1 #0 (, $binding/1)}) body/0]
+                                             [(` {2 #0 (, $binding/2)}) body/0]
+                                             [(` {2 #1 (, $binding/2)}) body/0])
+                                       archive.empty)
+                                     (//type.expecting output/0))]
+                       (in false))
+                     //scope.with
+                     (//module.with 0 module/0)
+                     (//phase#each (|>> product.right product.right))
+                     (//phase.result state)
+                     (exception.otherwise (text.contains? (the exception.#label /.sum_has_no_case))))))
+             (_.coverage [/.mismatch]
+               (let [slot/0 (%.code $binding/0)
+                     slot/1 (%.code $binding/1)
+                     slot/2 (%.code $binding/2)
+
+                     slots/* (list slot/0 slot/1 slot/2)
+                     :record: {.#Named [module/0 name/0] (type.tuple (list input/0 input/1 input/2))}
+
+                     slot/0 (code.symbol [module/0 slot/0])
+                     slot/1 (code.symbol [module/0 slot/1])
+                     slot/2 (code.symbol [module/0 slot/2])]
+                 (and (|> (do //phase.monad
+                            [analysis (|> (` (, simple/0))
+                                          (/.when ..analysis
+                                            (list [(` {0 #0 (, $binding/0)}) body/0]
+                                                  [(` {1 #0 (, $binding/1)}) body/0]
+                                                  [(` {1 #1 (, $binding/2)}) body/0])
+                                            archive.empty)
+                                          (//type.expecting output/0))]
+                            (in false))
+                          //scope.with
+                          (//module.with 0 module/0)
+                          (//phase#each (|>> product.right product.right))
+                          (//phase.result state)
+                          (exception.otherwise (text.contains? (the exception.#label /.mismatch))))
+                      (|> (do //phase.monad
+                            [_ (//module.declare_labels true slots/* false :record:)
+                             analysis (|> (` (, simple/0))
+                                          (/.when ..analysis
+                                            (list [(` [(, slot/0) (, $binding/0)
+                                                       (, slot/1) (, $binding/1)
+                                                       (, slot/2) (, $binding/2)]) body/0])
+                                            archive.empty)
+                                          (//type.expecting output/0))]
+                            (in false))
+                          //scope.with
+                          (//module.with 0 module/0)
+                          (//phase#each (|>> product.right product.right))
+                          (//phase.result state)
+                          (exception.otherwise (text.contains? (the exception.#label /.mismatch)))))))
+             
+             ..test|tuple
+             ))))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension.lux
index 8daf0cd19..e884cd858 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension.lux
@@ -123,7 +123,7 @@
                  (/.install extender extension handler/1))
                (phase.result [/.#bundle /.empty
                               /.#state state])
-               (pipe.case
+               (pipe.when
                  {try.#Failure error}
                  (exception.match? /.cannot_overwrite error)
 
@@ -135,7 +135,7 @@
                         [extension (list left right)])
                (phase.result [/.#bundle /.empty
                               /.#state state])
-               (pipe.case
+               (pipe.when
                  {try.#Failure error}
                  (exception.match? /.unknown error)
 
@@ -200,7 +200,7 @@
                               (/.apply archive.empty phase [extension (list)]))
                             (phase.result [/.#bundle /.empty
                                            /.#state state])
-                            (pipe.case
+                            (pipe.when
                               {try.#Failure error}
                               (exception.match? /.incorrect_arity error)
 
@@ -215,7 +215,7 @@
                               (/.apply archive.empty phase [extension (list left right)]))
                             (phase.result [/.#bundle /.empty
                                            /.#state state])
-                            (pipe.case
+                            (pipe.when
                               {try.#Failure error}
                               (exception.match? /.invalid_syntax error)
 
@@ -257,7 +257,7 @@
                                      (/.lifted (phase.lifted {try.#Failure expected_error})))
                                  (phase.result [/.#bundle /.empty
                                                 /.#state state])
-                                 (pipe.case
+                                 (pipe.when
                                    {try.#Failure actual_error}
                                    (same? expected_error actual_error)
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension/analysis/lux.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension/analysis/lux.lux
index 5eff1f2b9..f100c1e07 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension/analysis/lux.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/extension/analysis/lux.lux
@@ -41,7 +41,7 @@
            (////type.with_type output_type
              (_primitive.phase archive.empty (` ((, (code.text procedure)) (,* params))))))
          (phase.result _primitive.state)
-         (pipe.case
+         (pipe.when
            {try.#Success _}
            
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/case.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/case.lux
deleted file mode 100644
index 8df7f087c..000000000
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/case.lux
+++ /dev/null
@@ -1,360 +0,0 @@
-(.require
- [library
-  [lux (.except)
-   [abstract
-    [hash (.only Hash)]
-    ["[0]" monad (.only do)]]
-   [control
-    ["[0]" pipe]
-    ["[0]" try (.use "[1]#[0]" functor)]]
-   [data
-    ["[0]" sum]
-    ["[0]" text (.only)
-     ["%" \\format (.only format)]]
-    [number
-     ["n" nat]
-     ["[0]" int]
-     ["[0]" rev]
-     ["[0]" frac]]
-    [collection
-     ["[0]" list (.use "[1]#[0]" functor mix monoid)]
-     ["[0]" set]]]
-   [math
-    ["[0]" random (.only Random)]]
-   [test
-    ["_" property (.only Test)]]]]
- ["[0]" //
-  ["[1][0]" primitive]]
- [\\
-  ["[0]" / (.only)
-   ["/[1]" // (.only)
-    ["/[1]" //
-     [extension
-      ["[1][0]" bundle]]
-     ["/[1]" // (.only)
-      ["[0]" analysis (.only Branch Match Analysis)]
-      ["[0]" synthesis (.only Path Synthesis)]
-      [///
-       ["[1][0]" reference (.only)
-        [variable (.only Register)]]
-       ["[0]" phase]
-       [meta
-        ["[0]" archive]]]]]]]])
-
-(def masking_test
-  Test
-  (do [! random.monad]
-    [maskedA //primitive.primitive
-     temp (|> random.nat (at ! each (n.% 100)))
-     .let [maskA (analysis.case
-                   [maskedA
-                    [[{analysis.#Bind temp}
-                      {analysis.#Reference (////reference.local temp)}]
-                     (list)]])]]
-    (_.coverage [/.synthesize_masking]
-      (|> maskA
-          (//.phase archive.empty)
-          (phase.result [///bundle.empty synthesis.init])
-          (try#each (//primitive.corresponds? maskedA))
-          (try.default false)))))
-
-(def let_test
-  Test
-  (do random.monad
-    [registerA random.nat
-     inputA //primitive.primitive
-     outputA //primitive.primitive
-     .let [letA (analysis.case
-                  [inputA
-                   [[{analysis.#Bind registerA}
-                     outputA]
-                    (list)]])]]
-    (_.coverage [/.synthesize_let]
-      (|> letA
-          (//.phase archive.empty)
-          (phase.result [///bundle.empty synthesis.init])
-          (pipe.case
-            {try.#Success (synthesis.branch/let [inputS registerS outputS])}
-            (and (n.= registerA registerS)
-                 (//primitive.corresponds? inputA inputS)
-                 (//primitive.corresponds? outputA outputS))
-
-            _
-            false)))))
-
-(def if_test
-  Test
-  (do random.monad
-    [then|else random.bit
-     inputA //primitive.primitive
-     thenA //primitive.primitive
-     elseA //primitive.primitive
-     .let [thenB (is Branch
-                     [{analysis.#Simple {analysis.#Bit true}}
-                      thenA])
-           elseB (is Branch
-                     [{analysis.#Simple {analysis.#Bit false}}
-                      elseA])
-           ifA (if then|else
-                 (analysis.case [inputA [thenB (list elseB)]])
-                 (analysis.case [inputA [elseB (list thenB)]]))]]
-    (_.coverage [/.synthesize_if]
-      (|> ifA
-          (//.phase archive.empty)
-          (phase.result [///bundle.empty synthesis.init])
-          (pipe.case
-            {try.#Success (synthesis.branch/if [inputS thenS elseS])}
-            (and (//primitive.corresponds? inputA inputS)
-                 (//primitive.corresponds? thenA thenS)
-                 (//primitive.corresponds? elseA elseS))
-
-            _
-            false)))))
-
-(def random_member
-  (Random synthesis.Member)
-  (do [! random.monad]
-    [lefts (|> random.nat (at ! each (n.% 10)))
-     right? random.bit]
-    (in (if right?
-          {.#Right lefts}
-          {.#Left lefts}))))
-
-(def random_path
-  (Random (analysis.Tuple synthesis.Member))
-  (do [! random.monad]
-    [size_1 (|> random.nat (at ! each (|>> (n.% 10) ++)))]
-    (random.list size_1 ..random_member)))
-
-(def (get_pattern path)
-  (-> (analysis.Tuple synthesis.Member)
-      (Random [analysis.Pattern Register]))
-  (do random.monad
-    [@member random.nat]
-    (in [(list#mix (function (_ member inner)
-                     (case member
-                       {.#Left lefts}
-                       (analysis.pattern/tuple
-                        (list#composite (list.repeated lefts (analysis.pattern/unit))
-                                        (list inner (analysis.pattern/unit))))
-                       
-                       {.#Right lefts}
-                       (analysis.pattern/tuple
-                        (list#composite (list.repeated (++ lefts) (analysis.pattern/unit))
-                                        (list inner)))))
-                   {analysis.#Bind @member}
-                   (list.reversed path))
-         @member])))
-
-(def get_test
-  Test
-  (do [! random.monad]
-    [recordA (|> random.nat
-                 (at ! each (|>> analysis.nat))
-                 (random.list 10)
-                 (at ! each (|>> analysis.tuple)))
-     pathA ..random_path
-     [pattern @member] (get_pattern pathA)
-     .let [getA (analysis.case [recordA [[pattern
-                                          {analysis.#Reference (////reference.local @member)}]
-                                         (list)]])]]
-    (_.coverage [/.synthesize_get]
-      (|> getA
-          (//.phase archive.empty)
-          (phase.result [///bundle.empty synthesis.init])
-          (pipe.case
-            {try.#Success (synthesis.branch/get [pathS recordS])}
-            (and (at (list.equivalence (sum.equivalence n.= n.=)) = pathA pathS)
-                 (//primitive.corresponds? recordA recordS))
-
-            _
-            false)))))
-
-(def random_bit
-  (Random [Path Match])
-  (do [! random.monad]
-    [test random.bit
-     then random.nat
-     else random.nat]
-    (in [{synthesis.#Alt {synthesis.#Seq (synthesis.path/bit test)
-                                         {synthesis.#Then (synthesis.i64 (.i64 then))}}
-                         {synthesis.#Seq (synthesis.path/bit (not test))
-                                         {synthesis.#Then (synthesis.i64 (.i64 else))}}}
-         [[analysis.#when (analysis.pattern/bit test)
-           analysis.#then (analysis.nat then)]
-          (list [analysis.#when (analysis.pattern/bit (not test))
-                 analysis.#then (analysis.nat else)])]])))
-
-(def (random_five hash random_element)
-  (All (_ a) (-> (Hash a) (Random a) (Random [a a a a a])))
-  (|> random_element
-      (random.set hash 5)
-      (at random.monad each (|>> set.list
-                                 (pipe.case
-                                   (list s0 s1 s2 s3 s4)
-                                   [s0 s1 s2 s3 s4]
-
-                                   _
-                                   (undefined))))))
-
-(with_template [      ]
-  [(def 
-     (Random [Path Match])
-     (do [! random.monad]
-       [[test/0 test/1 test/2 test/3 test/4] (random_five  )
-        [body/0 body/1 body/2 body/3 body/4] (random_five  )]
-       (in [(all {synthesis.#Alt}
-                 {synthesis.#Seq ( test/0) {synthesis.#Then ( body/0)}}
-                 {synthesis.#Seq ( test/1) {synthesis.#Then ( body/1)}}
-                 {synthesis.#Seq ( test/2) {synthesis.#Then ( body/2)}}
-                 {synthesis.#Seq ( test/3) {synthesis.#Then ( body/3)}}
-                 {synthesis.#Seq ( test/4) {synthesis.#Then ( body/4)}})
-            [[analysis.#when ( test/0) analysis.#then ( body/0)]
-             (list [analysis.#when ( test/1) analysis.#then ( body/1)]
-                   [analysis.#when ( test/2) analysis.#then ( body/2)]
-                   [analysis.#when ( test/3) analysis.#then ( body/3)]
-                   [analysis.#when ( test/4) analysis.#then ( body/4)])]])))]
-
-  [random_nat n.hash random.nat (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/nat analysis.nat]
-  [random_int int.hash random.int (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/int analysis.int]
-  [random_rev rev.hash random.rev (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/rev analysis.rev]
-  [random_frac frac.hash random.frac synthesis.path/f64 synthesis.f64 analysis.pattern/frac analysis.frac]
-  [random_text text.hash (random.unicode 1) synthesis.path/text synthesis.text analysis.pattern/text analysis.text]
-  )
-
-(def random_simple
-  (all random.either
-       ..random_bit
-       ..random_nat
-       ..random_int
-       ..random_rev
-       ..random_frac
-       ..random_text
-       ))
-
-(def random_variant
-  (Random [Path Match])
-  (do [! random.monad]
-    [[lefts/0 lefts/1 lefts/2 lefts/3 lefts/4] (random_five n.hash random.nat)
-     [value/0 value/1 value/2 value/3 value/4] (random_five text.hash (random.unicode 1))
-     last_is_right? random.bit
-     [body/0 body/1 body/2 body/3 body/4] (random_five frac.hash random.frac)
-     .let [path (is (-> Nat Bit Text Frac Path)
-                    (function (_ lefts right? value body)
-                      (all {synthesis.#Seq}
-                           (synthesis.path/side (if right?
-                                                  {.#Right lefts}
-                                                  {.#Left lefts}))
-                           (synthesis.path/text value)
-                           {synthesis.#Then (synthesis.f64 body)})))
-           branch (is (-> Nat Bit Text Frac Branch)
-                      (function (_ lefts right? value body)
-                        [analysis.#when (analysis.pattern/variant [analysis.#lefts lefts
-                                                                   analysis.#right? right?
-                                                                   analysis.#value (analysis.pattern/text value)])
-                         analysis.#then (analysis.frac body)]))]]
-    (in [(all {synthesis.#Alt}
-              (path lefts/0 false value/0 body/0)
-              (path lefts/1 false value/1 body/1)
-              (path lefts/2 false value/2 body/2)
-              (path lefts/3 false value/3 body/3)
-              (path lefts/4 last_is_right? value/4 body/4))
-         [(branch lefts/0 false value/0 body/0)
-          (list (branch lefts/1 false value/1 body/1)
-                (branch lefts/2 false value/2 body/2)
-                (branch lefts/3 false value/3 body/3)
-                (branch lefts/4 last_is_right? value/4 body/4))]])))
-
-(def random_tuple
-  (Random [Path Match])
-  (do [! random.monad]
-    [mid_size (at ! each (n.% 4) random.nat)
-
-     value/first (random.unicode 1)
-     value/mid (random.list mid_size (random.unicode 1))
-     value/last (random.unicode 1)
-
-     body/first random.frac
-     body/mid (random.list mid_size random.frac)
-     body/last random.frac
-     .let [path (is (-> Nat Bit Text Frac Path)
-                    (function (_ lefts right? value body)
-                      (if right?
-                        (all {synthesis.#Seq}
-                             (synthesis.path/member (if right?
-                                                      {.#Right lefts}
-                                                      {.#Left lefts}))
-                             (synthesis.path/text value)
-                             {synthesis.#Then (synthesis.f64 body)})
-                        (all {synthesis.#Seq}
-                             (synthesis.path/member (if right?
-                                                      {.#Right lefts}
-                                                      {.#Left lefts}))
-                             (synthesis.path/text value)
-                             {synthesis.#Pop}
-                             {synthesis.#Then (synthesis.f64 body)}))))
-           branch (is (-> Nat Bit Text Frac Branch)
-                      (function (_ lefts right? value body)
-                        [analysis.#when (if right?
-                                          (analysis.pattern/tuple (list#composite (list.repeated (++ lefts) (analysis.pattern/unit))
-                                                                                  (list (analysis.pattern/text value))))
-                                          (analysis.pattern/tuple (all list#composite
-                                                                       (list.repeated lefts (analysis.pattern/unit))
-                                                                       (list (analysis.pattern/text value)
-                                                                             (analysis.pattern/unit)))))
-                         analysis.#then (analysis.frac body)]))]]
-    (in [(list#mix (function (_ left right)
-                     {synthesis.#Alt left right})
-                   (path (++ mid_size) true value/last body/last)
-                   (|> (list.zipped_2 value/mid body/mid)
-                       {.#Item [value/first body/first]}
-                       list.enumeration
-                       (list#each (function (_ [lefts' [value body]])
-                                    (path lefts' false value body)))
-                       list.reversed))
-         [(branch 0 false value/first body/first)
-          (list#composite (|> (list.zipped_2 value/mid body/mid)
-                              list.enumeration
-                              (list#each (function (_ [lefts' [value body]])
-                                           (branch (++ lefts') false value body))))
-                          (list (branch (++ mid_size) true value/last body/last)))]])))
-
-(def random_complex
-  (all random.either
-       ..random_variant
-       ..random_tuple
-       ))
-
-(def random_case
-  (all random.either
-       ..random_simple
-       ..random_complex
-       ))
-
-(def case_test
-  Test
-  (do [! random.monad]
-    [expected_input (at ! each (|>> .i64 synthesis.i64) random.nat)
-     [expected_path match] ..random_case]
-    (_.coverage [/.synthesize_case]
-      (|> (/.synthesize_case //.phase archive.empty expected_input match)
-          (phase.result [///bundle.empty synthesis.init])
-          (pipe.case
-            {try.#Success (synthesis.branch/case [actual_input actual_path])}
-            (and (at synthesis.equivalence = expected_input actual_input)
-                 (at synthesis.path_equivalence = expected_path actual_path))
-
-            _
-            false)))))
-
-(def .public test
-  Test
-  (<| (_.covering /._)
-      (_.for [/.synthesize])
-      (all _.and
-           ..masking_test
-           ..let_test
-           ..if_test
-           ..get_test
-           ..case_test
-           )))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/function.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/function.lux
index 35acd02b6..33b02eaf7 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/function.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/function.lux
@@ -56,7 +56,7 @@
 (def (n_abstraction arity body)
   (-> Arity Analysis Analysis)
   (list#mix (function (_ arity_1 body)
-              (case arity_1
+              (when arity_1
                 0 {analysis.#Function (list) body}
                 _ {analysis.#Function (all list#composite
                                            (list#each (|>> {variable.#Foreign})
@@ -68,7 +68,7 @@
 
 (def !expect
   (template (_  )
-    (case 
+    (when 
       
       true
       
@@ -174,7 +174,7 @@
   (random.either (..random_variable arity output?)
                  (..random_constant output?)))
 
-(def (random_case arity random_value output?)
+(def (random_when arity random_value output?)
   (-> Arity Scenario Scenario)
   (do [! random.monad]
     [bit_test random.bit
@@ -190,7 +190,7 @@
                          {.#Left lefts})]]
     (in [(and loop?_input
               loop?_output)
-         (synthesis.branch/case [expected_input
+         (synthesis.branch/when [expected_input
                                  (all synthesis.path/alt
                                       (synthesis.path/then expected_output)
                                       (synthesis.path/seq (synthesis.path/bit bit_test)
@@ -217,7 +217,7 @@
                                              (synthesis.path/bind (++ arity))
                                              synthesis.path/pop
                                              (synthesis.path/then expected_output))))])
-         {analysis.#Case actual_input
+         {analysis.#When actual_input
                          [[analysis.#when (analysis.pattern/unit)
                            analysis.#then actual_output]
                           (list [analysis.#when (analysis.pattern/bit bit_test)
@@ -252,7 +252,7 @@
          (synthesis.branch/let [expected_input
                                 (++ arity)
                                 expected_output])
-         {analysis.#Case actual_input
+         {analysis.#When actual_input
                          [[analysis.#when {analysis.#Bind 2}
                            analysis.#then actual_output]
                           (list)]}])))
@@ -271,12 +271,12 @@
                                expected_then
                                expected_else])
          (if flip?
-           {analysis.#Case actual_test
+           {analysis.#When actual_test
                            [[analysis.#when (analysis.pattern/bit false)
                              analysis.#then actual_else]
                             (list [analysis.#when (analysis.pattern/bit true)
                                    analysis.#then actual_then])]}
-           {analysis.#Case actual_test
+           {analysis.#When actual_test
                            [[analysis.#when (analysis.pattern/bit true)
                              analysis.#then actual_then]
                             (list [analysis.#when (analysis.pattern/bit false)
@@ -293,7 +293,7 @@
                                         {.#Right lefts}
                                         {.#Left lefts}))
                                 expected_record])
-         {analysis.#Case actual_record
+         {analysis.#When actual_record
                          [[analysis.#when (analysis.pattern/tuple
                                            (list#composite (list.repeated lefts (analysis.pattern/unit))
                                                            (if right?
@@ -304,7 +304,7 @@
 
 (def (random_branch arity random_value output?)
   (-> Arity Scenario Scenario)
-  (random.either (random.either (..random_case arity random_value output?)
+  (random.either (random.either (..random_when arity random_value output?)
                                 (..random_let arity random_value output?))
                  (random.either (..random_if random_value output?)
                                 (..random_get random_value output?))))
@@ -315,7 +315,7 @@
     [resets (random.list arity (random_value false))]
     (in [true
          (synthesis.loop/again (list#each (|>> product.right product.left) resets))
-         (analysis.apply [{analysis.#Reference (case arity
+         (analysis.apply [{analysis.#Reference (when arity
                                                  1 (reference.local 0)
                                                  _ (reference.foreign 0))}
                           (list#each (|>> product.right product.right) resets)])])))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/loop.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/loop.lux
index d2fa415a0..2fa13fdb7 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/loop.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/loop.lux
@@ -61,7 +61,7 @@
                 (in [next
                      [{variable.#Local (/.register_optimization offset register)}
                       {variable.#Local register}]]))]
-    (case offset
+    (when offset
       0 local
       _ (all random.either
              local
@@ -193,8 +193,8 @@
                 [[next [inputE inputA]] (..reference offset arity next)
                  [next [pathE pathA]] (..path offset arity next)]
                 (in [next
-                     [(//.branch/case [inputE pathE])
-                      (//.branch/case [inputA pathA])]])))
+                     [(//.branch/when [inputE pathE])
+                      (//.branch/when [inputA pathA])]])))
          )))
 
 (def (loop offset arity next)
@@ -275,7 +275,7 @@
                                  (random.list arity))
               [_ [expected iteration]] (..scenario expected_offset arity 0)]
              (_.coverage [/.Transform /.optimization /.register_optimization]
-               (case (/.optimization true expected_offset expected_inits
+               (when (/.optimization true expected_offset expected_inits
                                      [//.#environment (|> expected_offset
                                                           list.indices
                                                           (list#each (|>> {variable.#Local})))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/primitive.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/primitive.lux
index e9d5451ef..a12f284a3 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/primitive.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/primitive.lux
@@ -46,7 +46,7 @@
 
 (def .public (corresponds? analysis synthesis)
   (-> Analysis Synthesis Bit)
-  (`` (case [analysis synthesis]
+  (`` (when [analysis synthesis]
         (,, (with_template [   ]
               [[{////analysis.#Primitive { expected}}
                 {////synthesis.#Primitive { actual}}]
@@ -84,7 +84,7 @@
                           (|> {////analysis.#Primitive { expected}}
                               (//.phase archive.empty)
                               (phase.result [///bundle.empty ////synthesis.init])
-                              (pipe.case
+                              (pipe.when
                                 {try.#Success {////synthesis.#Primitive { actual}}}
                                 (same? expected actual)
 
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/structure.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/structure.lux
index 904f98b43..055f1440a 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/structure.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/structure.lux
@@ -50,7 +50,7 @@
       (|> (////analysis.variant [lefts right? memberA])
           (//.phase archive.empty)
           (phase.result [///bundle.empty ////synthesis.init])
-          (pipe.case
+          (pipe.when
             {try.#Success (////synthesis.variant [leftsS right?S valueS])}
             (let [tagS (if right?S (++ leftsS) leftsS)]
               (and (n.= tagA tagS)
@@ -69,7 +69,7 @@
       (|> (////analysis.tuple membersA)
           (//.phase archive.empty)
           (phase.result [///bundle.empty ////synthesis.init])
-          (pipe.case
+          (pipe.when
             {try.#Success (////synthesis.tuple membersS)}
             (and (n.= size (list.size membersS))
                  (list.every? (product.uncurried //primitive.corresponds?)
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/variable.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/variable.lux
index fe6ec126b..ff011a319 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/variable.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/variable.lux
@@ -32,7 +32,7 @@
 
 (def !expect
   (template (_  )
-    (case 
+    (when 
       
       true
       
@@ -78,12 +78,12 @@
          .let [fake_register (n.+ (the #redundants context)
                                   (dictionary.size (the #necessary context)))]
          [expected_output actual_output] (scenario (revised #redundants ++ context))]
-        (in [(synthesis.branch/case [expected_input
+        (in [(synthesis.branch/when [expected_input
                                      {synthesis.#Seq {synthesis.#Pop}
                                                      {synthesis.#Then expected_output}}])
              (if let?
                (synthesis.branch/let [actual_input fake_register actual_output])
-               (synthesis.branch/case [actual_input
+               (synthesis.branch/when [actual_input
                                        {synthesis.#Seq {synthesis.#Bind fake_register}
                                                        {synthesis.#Seq {synthesis.#Pop}
                                                                        {synthesis.#Then actual_output}}}]))]))
@@ -219,14 +219,14 @@
                   {synthesis.#Alt actual_left actual_right}]))
            )))
 
-(def (case_scenario scenario context)
+(def (when_scenario scenario context)
   (-> (Scenario Synthesis) (Scenario Synthesis))
   (do [! random.monad]
     [_ (in [])
      [expected_input actual_input] (scenario context)
      [expected_path actual_path] (..path_scenario scenario context)]
-    (in [(synthesis.branch/case [expected_input expected_path])
-         (synthesis.branch/case [actual_input actual_path])])))
+    (in [(synthesis.branch/when [expected_input expected_path])
+         (synthesis.branch/when [actual_input actual_path])])))
 
 (def (branch_scenario scenario context)
   (-> (Scenario Synthesis) (Scenario Synthesis))
@@ -234,7 +234,7 @@
        (..let_scenario scenario context)
        (..if_scenario scenario context)
        (..get_scenario scenario context)
-       (..case_scenario scenario context)
+       (..when_scenario scenario context)
        ))
 
 (def scope_arity 5)
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/when.lux b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/when.lux
new file mode 100644
index 000000000..65350ce95
--- /dev/null
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/phase/synthesis/when.lux
@@ -0,0 +1,360 @@
+(.require
+ [library
+  [lux (.except)
+   [abstract
+    [hash (.only Hash)]
+    ["[0]" monad (.only do)]]
+   [control
+    ["[0]" pipe]
+    ["[0]" try (.use "[1]#[0]" functor)]]
+   [data
+    ["[0]" sum]
+    ["[0]" text (.only)
+     ["%" \\format (.only format)]]
+    [number
+     ["n" nat]
+     ["[0]" int]
+     ["[0]" rev]
+     ["[0]" frac]]
+    [collection
+     ["[0]" list (.use "[1]#[0]" functor mix monoid)]
+     ["[0]" set]]]
+   [math
+    ["[0]" random (.only Random)]]
+   [test
+    ["_" property (.only Test)]]]]
+ ["[0]" //
+  ["[1][0]" primitive]]
+ [\\
+  ["[0]" / (.only)
+   ["/[1]" // (.only)
+    ["/[1]" //
+     [extension
+      ["[1][0]" bundle]]
+     ["/[1]" // (.only)
+      ["[0]" analysis (.only Branch Match Analysis)]
+      ["[0]" synthesis (.only Path Synthesis)]
+      [///
+       ["[1][0]" reference (.only)
+        [variable (.only Register)]]
+       ["[0]" phase]
+       [meta
+        ["[0]" archive]]]]]]]])
+
+(def masking_test
+  Test
+  (do [! random.monad]
+    [maskedA //primitive.primitive
+     temp (|> random.nat (at ! each (n.% 100)))
+     .let [maskA (analysis.when
+                   [maskedA
+                    [[{analysis.#Bind temp}
+                      {analysis.#Reference (////reference.local temp)}]
+                     (list)]])]]
+    (_.coverage [/.synthesize_masking]
+      (|> maskA
+          (//.phase archive.empty)
+          (phase.result [///bundle.empty synthesis.init])
+          (try#each (//primitive.corresponds? maskedA))
+          (try.default false)))))
+
+(def let_test
+  Test
+  (do random.monad
+    [registerA random.nat
+     inputA //primitive.primitive
+     outputA //primitive.primitive
+     .let [letA (analysis.when
+                  [inputA
+                   [[{analysis.#Bind registerA}
+                     outputA]
+                    (list)]])]]
+    (_.coverage [/.synthesize_let]
+      (|> letA
+          (//.phase archive.empty)
+          (phase.result [///bundle.empty synthesis.init])
+          (pipe.when
+            {try.#Success (synthesis.branch/let [inputS registerS outputS])}
+            (and (n.= registerA registerS)
+                 (//primitive.corresponds? inputA inputS)
+                 (//primitive.corresponds? outputA outputS))
+
+            _
+            false)))))
+
+(def if_test
+  Test
+  (do random.monad
+    [then|else random.bit
+     inputA //primitive.primitive
+     thenA //primitive.primitive
+     elseA //primitive.primitive
+     .let [thenB (is Branch
+                     [{analysis.#Simple {analysis.#Bit true}}
+                      thenA])
+           elseB (is Branch
+                     [{analysis.#Simple {analysis.#Bit false}}
+                      elseA])
+           ifA (if then|else
+                 (analysis.when [inputA [thenB (list elseB)]])
+                 (analysis.when [inputA [elseB (list thenB)]]))]]
+    (_.coverage [/.synthesize_if]
+      (|> ifA
+          (//.phase archive.empty)
+          (phase.result [///bundle.empty synthesis.init])
+          (pipe.when
+            {try.#Success (synthesis.branch/if [inputS thenS elseS])}
+            (and (//primitive.corresponds? inputA inputS)
+                 (//primitive.corresponds? thenA thenS)
+                 (//primitive.corresponds? elseA elseS))
+
+            _
+            false)))))
+
+(def random_member
+  (Random synthesis.Member)
+  (do [! random.monad]
+    [lefts (|> random.nat (at ! each (n.% 10)))
+     right? random.bit]
+    (in (if right?
+          {.#Right lefts}
+          {.#Left lefts}))))
+
+(def random_path
+  (Random (analysis.Tuple synthesis.Member))
+  (do [! random.monad]
+    [size_1 (|> random.nat (at ! each (|>> (n.% 10) ++)))]
+    (random.list size_1 ..random_member)))
+
+(def (get_pattern path)
+  (-> (analysis.Tuple synthesis.Member)
+      (Random [analysis.Pattern Register]))
+  (do random.monad
+    [@member random.nat]
+    (in [(list#mix (function (_ member inner)
+                     (when member
+                       {.#Left lefts}
+                       (analysis.pattern/tuple
+                        (list#composite (list.repeated lefts (analysis.pattern/unit))
+                                        (list inner (analysis.pattern/unit))))
+                       
+                       {.#Right lefts}
+                       (analysis.pattern/tuple
+                        (list#composite (list.repeated (++ lefts) (analysis.pattern/unit))
+                                        (list inner)))))
+                   {analysis.#Bind @member}
+                   (list.reversed path))
+         @member])))
+
+(def get_test
+  Test
+  (do [! random.monad]
+    [recordA (|> random.nat
+                 (at ! each (|>> analysis.nat))
+                 (random.list 10)
+                 (at ! each (|>> analysis.tuple)))
+     pathA ..random_path
+     [pattern @member] (get_pattern pathA)
+     .let [getA (analysis.when [recordA [[pattern
+                                          {analysis.#Reference (////reference.local @member)}]
+                                         (list)]])]]
+    (_.coverage [/.synthesize_get]
+      (|> getA
+          (//.phase archive.empty)
+          (phase.result [///bundle.empty synthesis.init])
+          (pipe.when
+            {try.#Success (synthesis.branch/get [pathS recordS])}
+            (and (at (list.equivalence (sum.equivalence n.= n.=)) = pathA pathS)
+                 (//primitive.corresponds? recordA recordS))
+
+            _
+            false)))))
+
+(def random_bit
+  (Random [Path Match])
+  (do [! random.monad]
+    [test random.bit
+     then random.nat
+     else random.nat]
+    (in [{synthesis.#Alt {synthesis.#Seq (synthesis.path/bit test)
+                                         {synthesis.#Then (synthesis.i64 (.i64 then))}}
+                         {synthesis.#Seq (synthesis.path/bit (not test))
+                                         {synthesis.#Then (synthesis.i64 (.i64 else))}}}
+         [[analysis.#when (analysis.pattern/bit test)
+           analysis.#then (analysis.nat then)]
+          (list [analysis.#when (analysis.pattern/bit (not test))
+                 analysis.#then (analysis.nat else)])]])))
+
+(def (random_five hash random_element)
+  (All (_ a) (-> (Hash a) (Random a) (Random [a a a a a])))
+  (|> random_element
+      (random.set hash 5)
+      (at random.monad each (|>> set.list
+                                 (pipe.when
+                                   (list s0 s1 s2 s3 s4)
+                                   [s0 s1 s2 s3 s4]
+
+                                   _
+                                   (undefined))))))
+
+(with_template [      ]
+  [(def 
+     (Random [Path Match])
+     (do [! random.monad]
+       [[test/0 test/1 test/2 test/3 test/4] (random_five  )
+        [body/0 body/1 body/2 body/3 body/4] (random_five  )]
+       (in [(all {synthesis.#Alt}
+                 {synthesis.#Seq ( test/0) {synthesis.#Then ( body/0)}}
+                 {synthesis.#Seq ( test/1) {synthesis.#Then ( body/1)}}
+                 {synthesis.#Seq ( test/2) {synthesis.#Then ( body/2)}}
+                 {synthesis.#Seq ( test/3) {synthesis.#Then ( body/3)}}
+                 {synthesis.#Seq ( test/4) {synthesis.#Then ( body/4)}})
+            [[analysis.#when ( test/0) analysis.#then ( body/0)]
+             (list [analysis.#when ( test/1) analysis.#then ( body/1)]
+                   [analysis.#when ( test/2) analysis.#then ( body/2)]
+                   [analysis.#when ( test/3) analysis.#then ( body/3)]
+                   [analysis.#when ( test/4) analysis.#then ( body/4)])]])))]
+
+  [random_nat n.hash random.nat (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/nat analysis.nat]
+  [random_int int.hash random.int (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/int analysis.int]
+  [random_rev rev.hash random.rev (|>> .i64 synthesis.path/i64) (|>> .i64 synthesis.i64) analysis.pattern/rev analysis.rev]
+  [random_frac frac.hash random.frac synthesis.path/f64 synthesis.f64 analysis.pattern/frac analysis.frac]
+  [random_text text.hash (random.unicode 1) synthesis.path/text synthesis.text analysis.pattern/text analysis.text]
+  )
+
+(def random_simple
+  (all random.either
+       ..random_bit
+       ..random_nat
+       ..random_int
+       ..random_rev
+       ..random_frac
+       ..random_text
+       ))
+
+(def random_variant
+  (Random [Path Match])
+  (do [! random.monad]
+    [[lefts/0 lefts/1 lefts/2 lefts/3 lefts/4] (random_five n.hash random.nat)
+     [value/0 value/1 value/2 value/3 value/4] (random_five text.hash (random.unicode 1))
+     last_is_right? random.bit
+     [body/0 body/1 body/2 body/3 body/4] (random_five frac.hash random.frac)
+     .let [path (is (-> Nat Bit Text Frac Path)
+                    (function (_ lefts right? value body)
+                      (all {synthesis.#Seq}
+                           (synthesis.path/side (if right?
+                                                  {.#Right lefts}
+                                                  {.#Left lefts}))
+                           (synthesis.path/text value)
+                           {synthesis.#Then (synthesis.f64 body)})))
+           branch (is (-> Nat Bit Text Frac Branch)
+                      (function (_ lefts right? value body)
+                        [analysis.#when (analysis.pattern/variant [analysis.#lefts lefts
+                                                                   analysis.#right? right?
+                                                                   analysis.#value (analysis.pattern/text value)])
+                         analysis.#then (analysis.frac body)]))]]
+    (in [(all {synthesis.#Alt}
+              (path lefts/0 false value/0 body/0)
+              (path lefts/1 false value/1 body/1)
+              (path lefts/2 false value/2 body/2)
+              (path lefts/3 false value/3 body/3)
+              (path lefts/4 last_is_right? value/4 body/4))
+         [(branch lefts/0 false value/0 body/0)
+          (list (branch lefts/1 false value/1 body/1)
+                (branch lefts/2 false value/2 body/2)
+                (branch lefts/3 false value/3 body/3)
+                (branch lefts/4 last_is_right? value/4 body/4))]])))
+
+(def random_tuple
+  (Random [Path Match])
+  (do [! random.monad]
+    [mid_size (at ! each (n.% 4) random.nat)
+
+     value/first (random.unicode 1)
+     value/mid (random.list mid_size (random.unicode 1))
+     value/last (random.unicode 1)
+
+     body/first random.frac
+     body/mid (random.list mid_size random.frac)
+     body/last random.frac
+     .let [path (is (-> Nat Bit Text Frac Path)
+                    (function (_ lefts right? value body)
+                      (if right?
+                        (all {synthesis.#Seq}
+                             (synthesis.path/member (if right?
+                                                      {.#Right lefts}
+                                                      {.#Left lefts}))
+                             (synthesis.path/text value)
+                             {synthesis.#Then (synthesis.f64 body)})
+                        (all {synthesis.#Seq}
+                             (synthesis.path/member (if right?
+                                                      {.#Right lefts}
+                                                      {.#Left lefts}))
+                             (synthesis.path/text value)
+                             {synthesis.#Pop}
+                             {synthesis.#Then (synthesis.f64 body)}))))
+           branch (is (-> Nat Bit Text Frac Branch)
+                      (function (_ lefts right? value body)
+                        [analysis.#when (if right?
+                                          (analysis.pattern/tuple (list#composite (list.repeated (++ lefts) (analysis.pattern/unit))
+                                                                                  (list (analysis.pattern/text value))))
+                                          (analysis.pattern/tuple (all list#composite
+                                                                       (list.repeated lefts (analysis.pattern/unit))
+                                                                       (list (analysis.pattern/text value)
+                                                                             (analysis.pattern/unit)))))
+                         analysis.#then (analysis.frac body)]))]]
+    (in [(list#mix (function (_ left right)
+                     {synthesis.#Alt left right})
+                   (path (++ mid_size) true value/last body/last)
+                   (|> (list.zipped_2 value/mid body/mid)
+                       {.#Item [value/first body/first]}
+                       list.enumeration
+                       (list#each (function (_ [lefts' [value body]])
+                                    (path lefts' false value body)))
+                       list.reversed))
+         [(branch 0 false value/first body/first)
+          (list#composite (|> (list.zipped_2 value/mid body/mid)
+                              list.enumeration
+                              (list#each (function (_ [lefts' [value body]])
+                                           (branch (++ lefts') false value body))))
+                          (list (branch (++ mid_size) true value/last body/last)))]])))
+
+(def random_complex
+  (all random.either
+       ..random_variant
+       ..random_tuple
+       ))
+
+(def random_when
+  (all random.either
+       ..random_simple
+       ..random_complex
+       ))
+
+(def when_test
+  Test
+  (do [! random.monad]
+    [expected_input (at ! each (|>> .i64 synthesis.i64) random.nat)
+     [expected_path match] ..random_when]
+    (_.coverage [/.synthesize_when]
+      (|> (/.synthesize_when //.phase archive.empty expected_input match)
+          (phase.result [///bundle.empty synthesis.init])
+          (pipe.when
+            {try.#Success (synthesis.branch/when [actual_input actual_path])}
+            (and (at synthesis.equivalence = expected_input actual_input)
+                 (at synthesis.path_equivalence = expected_path actual_path))
+
+            _
+            false)))))
+
+(def .public test
+  Test
+  (<| (_.covering /._)
+      (_.for [/.synthesize])
+      (all _.and
+           ..masking_test
+           ..let_test
+           ..if_test
+           ..get_test
+           ..when_test
+           )))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/syntax.lux b/stdlib/source/test/lux/meta/compiler/language/lux/syntax.lux
index d2c6a2a1f..ea75c4274 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/syntax.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/syntax.lux
@@ -77,7 +77,7 @@
     [sample code^]
     (all _.and
          (_.test "Can parse Lux code."
-           (case (let [source_code (%.code sample)]
+           (when (let [source_code (%.code sample)]
                    (/.parse "" (dictionary.empty text.hash) (text.size source_code)
                             [location.dummy 0 source_code]))
              {.#Left error}
@@ -90,13 +90,13 @@
            (_.test "Can parse multiple Lux code nodes."
              (let [source_code (format (%.code sample) " " (%.code other))
                    source_code//size (text.size source_code)]
-               (case (/.parse "" (dictionary.empty text.hash) source_code//size
+               (when (/.parse "" (dictionary.empty text.hash) source_code//size
                               [location.dummy 0 source_code])
                  {.#Left error}
                  false
 
                  {.#Right [remaining =sample]}
-                 (case (/.parse "" (dictionary.empty text.hash) source_code//size
+                 (when (/.parse "" (dictionary.empty text.hash) source_code//size
                                 remaining)
                    {.#Left error}
                    false
@@ -126,7 +126,7 @@
      comment comment^]
     (all _.and
          (_.test "Can handle comments."
-           (case (let [source_code (format comment (%.code sample))
+           (when (let [source_code (format comment (%.code sample))
                        source_code//size (text.size source_code)]
                    (/.parse "" (dictionary.empty text.hash) source_code//size
                             [location.dummy 0 source_code]))
diff --git a/stdlib/source/test/lux/meta/compiler/language/lux/synthesis.lux b/stdlib/source/test/lux/meta/compiler/language/lux/synthesis.lux
index 151567041..f1c85f69d 100644
--- a/stdlib/source/test/lux/meta/compiler/language/lux/synthesis.lux
+++ b/stdlib/source/test/lux/meta/compiler/language/lux/synthesis.lux
@@ -38,7 +38,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
diff --git a/stdlib/source/test/lux/meta/compiler/meta/archive.lux b/stdlib/source/test/lux/meta/compiler/meta/archive.lux
index 8195a009a..0f1db62b4 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/archive.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/archive.lux
@@ -150,7 +150,7 @@
                                /.#registry /registry.empty]]
                   archive (/.has module/0 entry archive)]
                  (in (and (list.empty? pre)
-                          (case (/.entries archive)
+                          (when (/.entries archive)
                             (list [module/0' @module/0' entry'])
                             (and (same? module/0 module/0')
                                  (same? @module/0 @module/0')
diff --git a/stdlib/source/test/lux/meta/compiler/meta/archive/module/document.lux b/stdlib/source/test/lux/meta/compiler/meta/archive/module/document.lux
index 4bd52fa23..3f31abaf7 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/archive/module/document.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/archive/module/document.lux
@@ -52,20 +52,20 @@
                (and (|> expected
                         (/.document key/0)
                         (/.marked? key/0)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success it} true
                           {try.#Failure error} false))
                     (|> expected
                         (/.document key/0)
                         (/.marked? key/1)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success it} false
                           {try.#Failure error} true))))
              (_.coverage [/.invalid_signature]
                (and (|> expected
                         (/.document key/0)
                         (/.content key/1)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success it}
                           false
                           
@@ -74,7 +74,7 @@
                     (|> expected
                         (/.document key/0)
                         (/.marked? key/1)
-                        (pipe.case
+                        (pipe.when
                           {try.#Success it}
                           false
                           
@@ -85,7 +85,7 @@
                    (/.document key/0)
                    (binaryF.result (/.format binaryF.nat))
                    (.result (/.parser key/0 .nat))
-                   (pipe.case
+                   (pipe.when
                      {try.#Success it}
                      (and (/signature#= signature/0 (/.signature it))
                           (|> it
diff --git a/stdlib/source/test/lux/meta/compiler/meta/archive/registry.lux b/stdlib/source/test/lux/meta/compiler/meta/archive/registry.lux
index b7e4e73b3..5cfb94750 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/archive/registry.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/archive/registry.lux
@@ -31,7 +31,7 @@
 
 (def tagged?
   (template (_  )
-    [(case 
+    [(when 
        { _}
        true
        
@@ -70,7 +70,7 @@
                        (n.= 0)))
                  (_.coverage [/.resource]
                    (let [[@it registry] (/.resource mandatory? expected_dependencies /.empty)]
-                     (case (sequence.list (/.artifacts registry))
+                     (when (sequence.list (/.artifacts registry))
                        (list [artifact actual_dependencies])
                        (and (same? @it (the artifact.#id artifact))
                             (same? mandatory? (the artifact.#mandatory? artifact))
@@ -84,17 +84,17 @@
                           (let [ '
                                  ']
                             (and (let [[@it registry] (  mandatory? expected_dependencies /.empty)]
-                                   (and (case ( registry)
+                                   (and (when ( registry)
                                           (list actual_name)
                                           (same?  actual_name)
 
                                           _
                                           false)
-                                        (case (sequence.list (/.artifacts registry))
+                                        (when (sequence.list (/.artifacts registry))
                                           (list [artifact actual_dependencies])
                                           (and (same? @it (the artifact.#id artifact))
                                                (same? mandatory? (the artifact.#mandatory? artifact))
-                                               (case (the artifact.#category artifact)
+                                               (when (the artifact.#category artifact)
                                                  { actual_name}
                                                  (same?  actual_name)
 
@@ -105,7 +105,7 @@
                                           _
                                           false)))
                                  (let [[@it registry] (  mandatory? expected_dependencies /.empty)]
-                                   (case ( registry)
+                                   (when ( registry)
                                      (list)
                                      true
 
diff --git a/stdlib/source/test/lux/meta/compiler/meta/cache.lux b/stdlib/source/test/lux/meta/compiler/meta/cache.lux
index fbff46fd2..53e8cd328 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/cache.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/cache.lux
@@ -42,7 +42,7 @@
                      (and (not pre/0)
                           (not pre/1)
                           
-                          (case outcome
+                          (when outcome
                             {try.#Success _} true
                             {try.#Failure _} false)
                           
diff --git a/stdlib/source/test/lux/meta/compiler/meta/cache/artifact.lux b/stdlib/source/test/lux/meta/compiler/meta/cache/artifact.lux
index 29a5f85b5..bf0faa128 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/cache/artifact.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/cache/artifact.lux
@@ -45,11 +45,11 @@
                     read! (/.cache fs context @module @artifact)]
                    (unit.coverage [/.path /.cache! /.cache]
                      (and (not pre)
-                          (case write!
+                          (when write!
                             {try.#Success _} true
                             {try.#Failure _} false)
                           post
-                          (case read!
+                          (when read!
                             {try.#Success actual} (binary#= expected actual)
                             {try.#Failure _} false)))))
              ))))
diff --git a/stdlib/source/test/lux/meta/compiler/meta/cache/module.lux b/stdlib/source/test/lux/meta/compiler/meta/cache/module.lux
index dbfb86c7f..243d395fc 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/cache/module.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/cache/module.lux
@@ -66,7 +66,7 @@
                      (and (not pre/0)
                           (not pre/1)
                           
-                          (case outcome
+                          (when outcome
                             {try.#Success _} true
                             {try.#Failure _} false)
                           
@@ -84,7 +84,7 @@
                      (and (not pre/0)
                           (not pre/1)
                           
-                          (case outcome
+                          (when outcome
                             {try.#Success _}
                             false
                             
diff --git a/stdlib/source/test/lux/meta/compiler/meta/cache/purge.lux b/stdlib/source/test/lux/meta/compiler/meta/cache/purge.lux
index 25d61d664..2a97eef8a 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/cache/purge.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/cache/purge.lux
@@ -133,7 +133,7 @@
                                        (in (and (at set.equivalence =
                                                     (set.of_list text.hash pre)
                                                     (set.of_list text.hash (list file/0 file/1)))
-                                                (case post
+                                                (when post
                                                   {try.#Failure error}
                                                   (exception.match? file.cannot_find_directory error)
 
diff --git a/stdlib/source/test/lux/meta/compiler/meta/cli.lux b/stdlib/source/test/lux/meta/compiler/meta/cli.lux
index b30db36b6..099f0344d 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/cli.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/cli.lux
@@ -62,7 +62,7 @@
                                    [(_.coverage []
                                       (|> (list.partial "build" compilation')
                                           (.result /.service)
-                                          (try#each (|>> (pipe.case
+                                          (try#each (|>> (pipe.when
                                                            {/.#Compilation it}
                                                            (|> it
                                                                (the )
@@ -85,7 +85,7 @@
                (`` (and (,, (with_template [ ]
                               [(|> (list.partial "repl" compilation')
                                    (.result /.service)
-                                   (try#each (|>> (pipe.case
+                                   (try#each (|>> (pipe.when
                                                     {/.#Interpretation it}
                                                     (|> it
                                                         (the )
@@ -107,7 +107,7 @@
                (`` (and (,, (with_template [ ]
                               [(|> (list.partial "export" export)
                                    (.result /.service)
-                                   (try#each (|>> (pipe.case
+                                   (try#each (|>> (pipe.when
                                                     {/.#Export it}
                                                     (|> it
                                                         
diff --git a/stdlib/source/test/lux/meta/compiler/meta/export.lux b/stdlib/source/test/lux/meta/compiler/meta/export.lux
index 484a411b1..ac3841ecc 100644
--- a/stdlib/source/test/lux/meta/compiler/meta/export.lux
+++ b/stdlib/source/test/lux/meta/compiler/meta/export.lux
@@ -80,7 +80,7 @@
                           (|> it
                               (try#each (|>> product.left
                                              sequence.list
-                                             (pipe.case
+                                             (pipe.when
                                                (list {tar.#Normal [actual_path/0 when/0 mode/0 ownership/0 actual_content/0]}
                                                      {tar.#Normal [actual_path/1 when/1 mode/1 ownership/1 actual_content/1]})
                                                (with_expansions [ (and (and (text#= file/0' (tar.from_path actual_path/0))
@@ -103,7 +103,7 @@
                           (|> it
                               (try#each (|>> product.right
                                              sequence.list
-                                             (pipe.case
+                                             (pipe.when
                                                (list {tar.#Normal [actual_path/0 _ _ _ actual_content/0]}
                                                      {tar.#Normal [actual_path/1 _ _ _ actual_content/1]})
                                                (with_expansions [ (and (and (text#= file/0' (tar.from_path actual_path/0))
diff --git a/stdlib/source/test/lux/meta/compiler/phase.lux b/stdlib/source/test/lux/meta/compiler/phase.lux
index b4ace0f20..18cad7805 100644
--- a/stdlib/source/test/lux/meta/compiler/phase.lux
+++ b/stdlib/source/test/lux/meta/compiler/phase.lux
@@ -34,7 +34,7 @@
 (def (comparison init)
   (All (_ s) (-> s (Comparison (/.Operation s))))
   (function (_ == left right)
-    (case [(/.result init left)
+    (when [(/.result init left)
            (/.result init right)]
       [{try.#Success left}
        {try.#Success right}]
@@ -55,7 +55,7 @@
          (_.coverage [/.failure]
            (|> (/.failure expected_error)
                (/.result state)
-               (pipe.case {try.#Failure actual_error}
+               (pipe.when {try.#Failure actual_error}
                  (same? expected_error actual_error)
 
                  _
@@ -63,7 +63,7 @@
          (_.coverage [/.lifted]
            (and (|> (/.lifted {try.#Failure expected_error})
                     (/.result state)
-                    (pipe.case {try.#Failure actual_error}
+                    (pipe.when {try.#Failure actual_error}
                       (same? expected_error actual_error)
 
                       _
@@ -75,7 +75,7 @@
          (_.coverage [/.except]
            (|> (/.except ..oops [])
                (/.result state)
-               (pipe.case {try.#Failure error}
+               (pipe.when {try.#Failure error}
                  (exception.match? ..oops error)
 
                  _
@@ -83,14 +83,14 @@
          (_.coverage [/.assertion]
            (and (|> (/.assertion ..oops [] false)
                     (/.result state)
-                    (pipe.case {try.#Failure error}
+                    (pipe.when {try.#Failure error}
                       (exception.match? ..oops error)
 
                       _
                       false))
                 (|> (/.assertion ..oops [] true)
                     (/.result state)
-                    (pipe.case {try.#Success _}
+                    (pipe.when {try.#Success _}
                       true
 
                       _
@@ -126,7 +126,7 @@
                                 (at n.hex encoded)
                                 (text#= state/hex)))))
                (/.result' state)
-               (pipe.case {try.#Success [state' verdict]}
+               (pipe.when {try.#Success [state' verdict]}
                  (and verdict
                       (n.= state state'))
 
@@ -148,7 +148,7 @@
          (_.coverage [/.result]
            (|> (at /.monad in expected)
                (/.result state)
-               (pipe.case {try.#Success actual}
+               (pipe.when {try.#Success actual}
                  (same? expected actual)
 
                  _
@@ -156,7 +156,7 @@
          (_.coverage [/.result']
            (|> (at /.monad in expected)
                (/.result' state)
-               (pipe.case {try.#Success [state' actual]}
+               (pipe.when {try.#Success [state' actual]}
                  (and (same? state state')
                       (same? expected actual))
 
@@ -187,7 +187,7 @@
                                           (at /.monad in (%.frac input)))))]
              (|> (phase archive.empty expected)
                  (/.result' [state/0 state/1])
-                 (pipe.case {try.#Success [[state/0' state/1'] actual]}
+                 (pipe.when {try.#Success [[state/0' state/1'] actual]}
                    (and (text#= (%.frac (i.frac expected)) actual)
                         (same? state/0 state/0')
                         (same? state/1 state/1'))
diff --git a/stdlib/source/test/lux/meta/compiler/reference.lux b/stdlib/source/test/lux/meta/compiler/reference.lux
index 9cbd38424..139ee891e 100644
--- a/stdlib/source/test/lux/meta/compiler/reference.lux
+++ b/stdlib/source/test/lux/meta/compiler/reference.lux
@@ -52,7 +52,7 @@
 
                (,, (with_template []
                      [(_.coverage []
-                        (case ( expected_register)
+                        (when ( expected_register)
                           ( actual_register)
                           (n.= expected_register actual_register)
 
@@ -65,20 +65,20 @@
 
                (_.coverage [/.variable /.self]
                  (and (at /.equivalence = (/.self) (/.variable (variable.self)))
-                      (case (/.self)
+                      (when (/.self)
                         (/.self)
                         true
                         
                         _
                         false)
-                      (case (/.variable (variable.self))
+                      (when (/.variable (variable.self))
                         (/.self)
                         true
                         
                         _
                         false)))
                (_.coverage [/.constant]
-                 (case (/.constant expected_constant)
+                 (when (/.constant expected_constant)
                    (/.constant actual_constant)
                    (symbol#= expected_constant actual_constant)
 
diff --git a/stdlib/source/test/lux/meta/compiler/reference/variable.lux b/stdlib/source/test/lux/meta/compiler/reference/variable.lux
index 6cb7c7c10..9fe14eec1 100644
--- a/stdlib/source/test/lux/meta/compiler/reference/variable.lux
+++ b/stdlib/source/test/lux/meta/compiler/reference/variable.lux
@@ -34,7 +34,7 @@
              (_.for [/.hash]
                     ($hash.spec /.hash ..random))
              (_.coverage [/.self]
-               (case (/.self)
+               (when (/.self)
                  (/.self) true
                  _ false))
              (_.coverage [/.self?]
diff --git a/stdlib/source/test/lux/meta/configuration.lux b/stdlib/source/test/lux/meta/configuration.lux
index e8ebe4980..8bc88d2d7 100644
--- a/stdlib/source/test/lux/meta/configuration.lux
+++ b/stdlib/source/test/lux/meta/configuration.lux
@@ -30,7 +30,7 @@
 
 (def .public (random amount)
   (-> Nat (Random /.Configuration))
-  (case amount
+  (when amount
     0 (random#in /.empty)
     _ (do [! random.monad]
         [feature (random.upper_case amount)
@@ -41,7 +41,7 @@
 (def failure
   (syntax (_ [it .any])
     (function (_ lux)
-      (case (expansion.complete it lux)
+      (when (expansion.complete it lux)
         {try.#Failure error}
         {try.#Success [lux (list (code.text error))]}
         
diff --git a/stdlib/source/test/lux/meta/macro.lux b/stdlib/source/test/lux/meta/macro.lux
index 792ed49eb..29f993f3a 100644
--- a/stdlib/source/test/lux/meta/macro.lux
+++ b/stdlib/source/test/lux/meta/macro.lux
@@ -38,7 +38,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
         true
        _ false)]))
 
@@ -114,7 +114,7 @@
 (def iterated
   (syntax (_ [cycle .nat
               it .any])
-    (in (list (case cycle
+    (in (list (when cycle
                 0 it
                 _ (` (..iterated (, (code.nat (-- cycle))) (, it))))))))
 
@@ -164,7 +164,7 @@
                                   (static.random code.nat
                                                          (random#each (|>> (n.% 5) ++) random.nat))
                                   (/.final (..iterated  ))]
-                 (case (' )
+                 (when (' )
                    [_ {.#Nat actual}]
                    (n.=  actual)
 
@@ -178,7 +178,7 @@
                                                          (random#each (|>> (n.% ) ++) random.nat))
                                   (/.times  (..iterated  ))]
                  (let [expected_remaining (n.-  )]
-                   (case (` )
+                   (when (` )
                      (^.` (..iterated (^., [_ {.#Nat actual_remaining}]) (^., [_ {.#Nat actual}])))
                      (and (n.= expected_remaining actual_remaining)
                           (n.=  actual))
@@ -191,7 +191,7 @@
   (macro (_ tokens)
     (loop (again [tokens tokens
                   output 0])
-      (case tokens
+      (when tokens
         {.#End}
         (at meta.monad in (list (code.nat output)))
         
diff --git a/stdlib/source/test/lux/meta/macro/local.lux b/stdlib/source/test/lux/meta/macro/local.lux
index eb58f416b..244c8ddd7 100644
--- a/stdlib/source/test/lux/meta/macro/local.lux
+++ b/stdlib/source/test/lux/meta/macro/local.lux
@@ -37,7 +37,7 @@
 (def macro_error
   (syntax (_ [macro .any])
     (function (_ compiler)
-      (case ((expansion.complete macro) compiler)
+      (when ((expansion.complete macro) compiler)
         {try.#Failure error}
         {try.#Success [compiler (list (code.text error))]}
         
diff --git a/stdlib/source/test/lux/meta/macro/pattern.lux b/stdlib/source/test/lux/meta/macro/pattern.lux
index 0b443cfd6..362cf42ba 100644
--- a/stdlib/source/test/lux/meta/macro/pattern.lux
+++ b/stdlib/source/test/lux/meta/macro/pattern.lux
@@ -44,7 +44,7 @@
              (do [! random.monad]
                [sample (at ! each (n.% 5) random.nat)]
                (_.coverage [/.with_template]
-                 (case sample
+                 (when sample
                    (/.with_template []
                      [ true])
                    ([0] [1] [2] [3] [4])
@@ -52,19 +52,19 @@
                    _
                    false)))
              (_.coverage [/.or]
-               (and (/.case expected_rev
+               (and (/.when expected_rev
                       (/.or .5 .25) true
                       _ false)
-                    (/.case expected_frac
+                    (/.when expected_frac
                       (/.or +0.5 +1.25) true
                       _ false)
-                    (/.case expected_text
+                    (/.when expected_text
                       (/.or "+0.5" "+1.25") true
                       _ false)))
              (_.coverage [/.let]
                (let [expected_pair (is (Pair Nat Int)
                                        [..#left expected_nat ..#right expected_int])]
-                 (/.case expected_pair
+                 (/.when expected_pair
                    (/.let actual_pair (!pair actual_left actual_right))
                    (and (/.same? expected_pair actual_pair)
                         (/.same? expected_nat actual_left)
@@ -72,7 +72,7 @@
              (_.coverage [/.multi]
                (let [expected_pair (is (Pair Nat Int)
                                        [..#left expected_nat ..#right expected_int])]
-                 (and (/.case expected_pair
+                 (and (/.when expected_pair
                         (/.multi (!pair 0 actual_right)
                                  [actual_right
                                   +0])
@@ -80,7 +80,7 @@
 
                         _
                         false)
-                      (/.case expected_pair
+                      (/.when expected_pair
                         (/.multi (!pair 0 actual_right)
                                  (i.= +0 actual_right))
                         true
@@ -88,12 +88,12 @@
                         _
                         false))))
              (_.coverage [/.|>]
-               (case expected_frac
+               (when expected_frac
                  (/.|> actual_frac [(f.* +2.0) (f.* +2.0)])
                  (f.= (f.* +4.0 expected_frac)
                       actual_frac)))
              (_.coverage [/.`]
-               (case (code.text expected_text)
+               (when (code.text expected_text)
                  (/.` "+0.5") true
                  (/.` "+1.25") true
                  _ false))
diff --git a/stdlib/source/test/lux/meta/macro/syntax/check.lux b/stdlib/source/test/lux/meta/macro/syntax/check.lux
index 72a8753f1..aac4bc781 100644
--- a/stdlib/source/test/lux/meta/macro/syntax/check.lux
+++ b/stdlib/source/test/lux/meta/macro/syntax/check.lux
@@ -38,7 +38,7 @@
            (do random.monad
              [[type value] ..random]
              (_.coverage [/.format /.parser]
-               (case (.result /.parser
+               (when (.result /.parser
                                     (list (/.format [/.#type type
                                                      /.#value value])))
                  {try.#Failure _}
diff --git a/stdlib/source/test/lux/meta/macro/syntax/declaration.lux b/stdlib/source/test/lux/meta/macro/syntax/declaration.lux
index 9a06513ed..090518338 100644
--- a/stdlib/source/test/lux/meta/macro/syntax/declaration.lux
+++ b/stdlib/source/test/lux/meta/macro/syntax/declaration.lux
@@ -40,7 +40,7 @@
            (do random.monad
              [expected ..random]
              (_.coverage [/.format /.parser]
-               (case (.result /.parser
+               (when (.result /.parser
                                     (list (/.format expected)))
                  {try.#Failure _}
                  false
diff --git a/stdlib/source/test/lux/meta/macro/syntax/definition.lux b/stdlib/source/test/lux/meta/macro/syntax/definition.lux
index 28aa3653d..929f841d6 100644
--- a/stdlib/source/test/lux/meta/macro/syntax/definition.lux
+++ b/stdlib/source/test/lux/meta/macro/syntax/definition.lux
@@ -68,7 +68,7 @@
               untyped_value $////code.random]
              (all _.and
                   (_.coverage [/.format /.parser]
-                    (case (.result (/.parser compiler)
+                    (when (.result (/.parser compiler)
                                          (list (/.format expected)))
                       {try.#Failure error}
                       false
@@ -77,7 +77,7 @@
                       (at /.equivalence = expected actual)))
                   (_.coverage [/.typed]
                     (let [expected (has /.#value {.#Left [type untyped_value]} expected)]
-                      (case (.result (/.typed compiler)
+                      (when (.result (/.typed compiler)
                                            (list (/.format expected)))
                         {try.#Failure error}
                         false
@@ -86,7 +86,7 @@
                         (at /.equivalence = expected actual))))
                   (_.coverage [/.lacks_type]
                     (let [expected (has /.#value {.#Right untyped_value} expected)]
-                      (case (.result (/.typed compiler)
+                      (when (.result (/.typed compiler)
                                            (list (/.format expected)))
                         {try.#Failure error}
                         (exception.match? /.lacks_type error)
diff --git a/stdlib/source/test/lux/meta/macro/syntax/export.lux b/stdlib/source/test/lux/meta/macro/syntax/export.lux
index b8109c5b6..e074f64ae 100644
--- a/stdlib/source/test/lux/meta/macro/syntax/export.lux
+++ b/stdlib/source/test/lux/meta/macro/syntax/export.lux
@@ -32,7 +32,7 @@
       (do random.monad
         [[expected_export_policy expected_un_exported] ..export]
         (_.coverage [/.parser /.default_policy]
-          (|> (case expected_export_policy
+          (|> (when expected_export_policy
                 {.#Some expected_export_policy}
                 (list expected_export_policy (code.nat expected_un_exported))
 
diff --git a/stdlib/source/test/lux/meta/macro/syntax/input.lux b/stdlib/source/test/lux/meta/macro/syntax/input.lux
index fffc345da..7f84d403d 100644
--- a/stdlib/source/test/lux/meta/macro/syntax/input.lux
+++ b/stdlib/source/test/lux/meta/macro/syntax/input.lux
@@ -42,7 +42,7 @@
            (do random.monad
              [expected ..random]
              (_.coverage [/.format /.parser]
-               (case (.result /.parser (list (/.format (list expected))))
+               (when (.result /.parser (list (/.format (list expected))))
                  {try.#Failure _}
                  false
                  
diff --git a/stdlib/source/test/lux/meta/macro/template.lux b/stdlib/source/test/lux/meta/macro/template.lux
index c9edbd035..655c52d73 100644
--- a/stdlib/source/test/lux/meta/macro/template.lux
+++ b/stdlib/source/test/lux/meta/macro/template.lux
@@ -33,7 +33,7 @@
 (def macro_error
   (syntax (_ [macro .any])
     (function (_ compiler)
-      (case ((expansion.complete macro) compiler)
+      (when ((expansion.complete macro) compiler)
         {try.#Failure error}
         {try.#Success [compiler (list (code.text error))]}
         
@@ -57,18 +57,18 @@
                      (list left mid right)
                      (`` (list (,, (/.spliced [left mid right]))))))
                (_.coverage [/.amount]
-                 (case (/.amount [left mid right])
+                 (when (/.amount [left mid right])
                    3 true
                    _ false))
                (_.coverage [/.text]
-                 (case (/.text )
+                 (when (/.text )
                    ' true
                    _ false))
                (_.coverage [/.symbol]
-                 (and (case (`` (symbol (,, (/.symbol ))))
+                 (and (when (`` (symbol (,, (/.symbol ))))
                         ["" '] true
                         _ false)
-                      (case (`` (symbol (,, (/.symbol  ))))
+                      (when (`` (symbol (,, (/.symbol  ))))
                         [' '] true
                         _ false)
                       ))
diff --git a/stdlib/source/test/lux/meta/static.lux b/stdlib/source/test/lux/meta/static.lux
index e030d74ac..a7169d6af 100644
--- a/stdlib/source/test/lux/meta/static.lux
+++ b/stdlib/source/test/lux/meta/static.lux
@@ -32,7 +32,7 @@
                         (with_expansions [ ()
                                            ()
                                            ( (<+>  ))]
-                          (case (' )
+                          (when (' )
                             [_ { l+r}]
                             (<=> l+r (<+>  ))
 
@@ -47,7 +47,7 @@
                  (with_expansions [ (/.random_frac)
                                     (/.random_frac)
                                     (/.frac (f.+  ))]
-                   (case (' )
+                   (when (' )
                      [_ {.#Frac l+r}]
                      (or (f.= l+r (f.+  ))
                          (and (f.not_a_number? l+r)
@@ -61,7 +61,7 @@
                  (with_expansions [ (/.random code.text (random.alpha_numeric 1))
                                     (/.random code.text (random.alpha_numeric 1))
                                     (/.text (format  ))]
-                   (case (' )
+                   (when (' )
                      [_ {.#Text l+r}]
                      (text#= l+r (format  ))
 
@@ -78,7 +78,7 @@
                  (with_expansions [ (/.random code.text (random.alpha_numeric 1))
                                     (/.random code.text (random.alpha_numeric 1))
                                     (/.literal code.text (format  ))]
-                   (case (' )
+                   (when (' )
                      [_ {.#Text l+r}]
                      (text#= l+r (format  ))
 
diff --git a/stdlib/source/test/lux/meta/target/js.lux b/stdlib/source/test/lux/meta/target/js.lux
index 759e0af3c..9867d5085 100644
--- a/stdlib/source/test/lux/meta/target/js.lux
+++ b/stdlib/source/test/lux/meta/target/js.lux
@@ -80,7 +80,7 @@
            (|> /.null
                ..eval
                (try#each (function (_ it)
-                           (case it
+                           (when it
                              {.#None} true
                              {.#Some _} false)))
                (try.else false)))
@@ -471,7 +471,7 @@
                                                   (/.while (/.< (/.int (.int full_inner_iterations)) $inner_index)
                                                            (all /.then
                                                                 (/.when (/.= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                                        /.break)
+                                                                  /.break)
                                                                 (/.set $output (/.+ $input $output))
                                                                 (/.set $inner_index (/.+ (/.int +1) $inner_index))
                                                                 ))
@@ -488,7 +488,7 @@
                                                            (all /.then
                                                                 (/.set $inner_index (/.+ (/.int +1) $inner_index))
                                                                 (/.when (/.<= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                                        /.continue)
+                                                                  /.continue)
                                                                 (/.set $output (/.+ $input $output))
                                                                 ))
                                                   (/.return $output)))
@@ -511,9 +511,9 @@
                                                                               (/.while (/.< (/.int (.int full_inner_iterations)) $inner_index)
                                                                                        (all /.then
                                                                                             (/.when (/.= (/.int (.int expected_outer_iterations)) $outer_index)
-                                                                                                    (/.break_at @outer))
+                                                                                              (/.break_at @outer))
                                                                                             (/.when (/.= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                                                                    /.break)
+                                                                                              /.break)
                                                                                             (/.set $output (/.+ $input $output))
                                                                                             (/.set $inner_index (/.+ (/.int +1) $inner_index))
                                                                                             ))
@@ -539,9 +539,9 @@
                                                                                        (all /.then
                                                                                             (/.set $inner_index (/.+ (/.int +1) $inner_index))
                                                                                             (/.when (/.<= (/.int (.int expected_outer_iterations)) $outer_index)
-                                                                                                    (/.continue_at @outer))
+                                                                                              (/.continue_at @outer))
                                                                                             (/.when (/.<= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                                                                    /.continue)
+                                                                                              /.continue)
                                                                                             (/.set $output (/.+ $input $output))
                                                                                             ))
                                                                               )
@@ -733,7 +733,7 @@
                        (/.apply (/.closure (list)
                                            (all /.then
                                                 (/.when (/.boolean ???)
-                                                        (/.return (/.number number/0)))
+                                                  (/.return (/.number number/0)))
                                                 (/.return (/.number number/1))))
                                 (list))))
          (_.coverage [/.switch]
@@ -819,7 +819,7 @@
                                                  (/.return $arg/0)))
                                  (list))
                         ..eval
-                        (pipe.case
+                        (pipe.when
                           {try.#Success it}
                           false
                           
diff --git a/stdlib/source/test/lux/meta/target/jvm.lux b/stdlib/source/test/lux/meta/target/jvm.lux
index 0e0da91da..b7c487680 100644
--- a/stdlib/source/test/lux/meta/target/jvm.lux
+++ b/stdlib/source/test/lux/meta/target/jvm.lux
@@ -125,7 +125,7 @@
   (do random.monad
     [class_name ..class_name
      method_name (random.upper_case 10)]
-    (in (case (do try.monad
+    (in (when (do try.monad
                 [class (/class.class /version.v6_0 /class.public
                          (/name.internal class_name)
                          {.#None}
@@ -914,7 +914,7 @@
                         (binary.result /class.format))
            loader (/loader.memory (/loader.new_library []))]]
     (_.test "PUTSTATIC & PUTFIELD & GETFIELD & GETSTATIC"
-      (case (do try.monad
+      (when (do try.monad
               [_ (/loader.define class_name bytecode loader)
                class (io.run! (/loader.load class_name loader))
                method (try (get_method static_method class))
@@ -1047,7 +1047,7 @@
                 .let [type (loop (again [dimensions dimensions
                                          type (is (Type Object)
                                                   ..$Object)])
-                             (case dimensions
+                             (when dimensions
                                0 type
                                _ (again (-- dimensions) (/type.array type))))]]
                (<| (_.lifted "MULTIANEWARRAY")
@@ -1351,7 +1351,7 @@
                                                          (random.only (|>> (text#= primitive_method_name) not)))
                                   expected (the #random primitive)
                                   .let [$Self (/type.class class_name (list))]]
-                                 (in (case (do try.monad
+                                 (in (when (do try.monad
                                              [class (/class.class /version.v6_0 /class.public
                                                       (/name.internal class_name)
                                                       {.#None}
@@ -1371,7 +1371,7 @@
                                                                             (list)
                                                                             {.#Some (do /.monad
                                                                                       [_ (/.invokestatic $Self primitive_method_name primitive_method_type)
-                                                                                       _ (case substitute
+                                                                                       _ (when substitute
                                                                                            {.#None}
                                                                                            (in [])
 
@@ -1734,7 +1734,7 @@
                                  (binary.result /class.format))
            loader (/loader.memory (/loader.new_library []))]]
     (_.test "Class & interface inheritance"
-      (case (do try.monad
+      (when (do try.monad
               [_ (/loader.define abstract_class abstract_bytecode loader)
                _ (/loader.define interface_class interface_bytecode loader)
                _ (/loader.define concrete_class concrete_bytecode loader)
diff --git a/stdlib/source/test/lux/meta/target/lua.lux b/stdlib/source/test/lux/meta/target/lua.lux
index 9b2cd6642..6d1ba7cb3 100644
--- a/stdlib/source/test/lux/meta/target/lua.lux
+++ b/stdlib/source/test/lux/meta/target/lua.lux
@@ -58,7 +58,7 @@
            (|> /.nil
                /.code
                ..load
-               (pipe.case
+               (pipe.when
                  {.#None} true
                  {.#Some _} false)))
          (_.coverage [/.boolean]
@@ -432,7 +432,7 @@
                                               (/.for_in (list $index $input) (/.ipairs/1 (/.array (list.repeated full_iterations $input)))
                                                         (all /.then
                                                              (/.when (/.> expected_iterations $index)
-                                                                     /.break)
+                                                               /.break)
                                                              (/.set (list $output) (/.+ $input $output))))
                                               (/.return $output))
                                          (/.closure (list $input))
@@ -446,7 +446,7 @@
                                              (/.while (/.< full_iterations $index)
                                                       (all /.then
                                                            (/.when (/.= expected_iterations $index)
-                                                                   /.break)
+                                                             /.break)
                                                            (/.set (list $output) (/.+ $input $output))
                                                            (/.set (list $index) (/.+ (/.int +1) $index))
                                                            ))
@@ -460,7 +460,7 @@
                                               (/.repeat (/.= full_iterations $index)
                                                         (all /.then
                                                              (/.when (/.= expected_iterations $index)
-                                                                     /.break)
+                                                               /.break)
                                                              (/.set (list $output) (/.+ $input $output))
                                                              (/.set (list $index) (/.+ (/.int +1) $index))
                                                              ))
@@ -473,7 +473,7 @@
                                                 (/.for_step $index (/.int +0) full_iterations (/.int +1)
                                                             (all /.then
                                                                  (/.when (/.= expected_iterations $index)
-                                                                         /.break)
+                                                                   /.break)
                                                                  (/.set (list $output) (/.+ $input $output))))
                                                 (/.return $output))
                                            (/.closure (list $input))
@@ -660,7 +660,7 @@
            (expression (|>> (as Frac) (f.= (if ??? float/0 float/1)))
                        (|> (all /.then
                                 (/.when (/.boolean ???)
-                                        (/.return (/.float float/0)))
+                                  (/.return (/.float float/0)))
                                 (/.return (/.float float/1)))
                            (/.closure (list))
                            (/.apply (list)))))
diff --git a/stdlib/source/test/lux/meta/target/python.lux b/stdlib/source/test/lux/meta/target/python.lux
index fdc5ef219..b346cb53a 100644
--- a/stdlib/source/test/lux/meta/target/python.lux
+++ b/stdlib/source/test/lux/meta/target/python.lux
@@ -57,7 +57,7 @@
                /.code
                ..eval
                (try#each (function (_ it)
-                           (case it
+                           (when it
                              {.#None} true
                              {.#Some _} false)))
                (try.else false)))
@@ -364,7 +364,7 @@
            keyword/0 (keyword 0)
            keyword/1 (keyword 1)
            keyword_choice (keyword poly_choice)]
-     .let [expected/? (case poly_choice
+     .let [expected/? (when poly_choice
                         0 expected/0
                         _ expected/1)]
      $var (at ! each (|>> %.nat (format "v") /.var) random.nat)
@@ -602,7 +602,7 @@
      $ex (at ! each (|>> %.nat (format "ex_") /.var) random.nat)]
     (all _.and
          (_.coverage [/.raise /.Exception/1]
-           (case (try (..statement
+           (when (try (..statement
                        (function (_ $output)
                          (all /.then
                               (/.raise (/.Exception/1 (/.string expected_error)))
@@ -623,7 +623,7 @@
                                      /.#handler (/.set (list $output) (/.float expected))]))))
                     (as Frac)
                     (f.= expected))
-                (case (try (..statement
+                (when (try (..statement
                             (function (_ $output)
                               (/.try (all /.then
                                           (/.raise (/.Exception/1 (/.string expected_error)))
@@ -781,7 +781,7 @@
                        (/.def $def (list)
                          (all /.then
                               (/.when (/.bool test)
-                                      (/.return (/.float then)))
+                                (/.return (/.float then)))
                               (/.return (/.float else))))
                        (/.set (list $output) (/.apply (list) $def)))))
                (as Frac)
diff --git a/stdlib/source/test/lux/meta/target/ruby.lux b/stdlib/source/test/lux/meta/target/ruby.lux
index 37395eeb2..779af9f0b 100644
--- a/stdlib/source/test/lux/meta/target/ruby.lux
+++ b/stdlib/source/test/lux/meta/target/ruby.lux
@@ -53,7 +53,7 @@
   (-> /.Expression Bit)
   (|>> /.code
        ..eval
-       (try#each (|>> (pipe.case
+       (try#each (|>> (pipe.when
                         {.#None} true
                         {.#Some _} false)))
        (try.else false)))
@@ -739,7 +739,7 @@
                                   (/.while (/.< (/.int (.int full_inner_iterations)) $inner_index)
                                            (all /.then
                                                 (/.when (/.= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                        /.break)
+                                                  /.break)
                                                 (/.set (list $output) (/.+ $input $output))
                                                 (/.set (list $inner_index) (/.+ (/.int +1) $inner_index))
                                                 ))
@@ -756,7 +756,7 @@
                                            (all /.then
                                                 (/.set (list $inner_index) (/.+ (/.int +1) $inner_index))
                                                 (/.when (/.<= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                        /.next)
+                                                  /.next)
                                                 (/.set (list $output) (/.+ $input $output))
                                                 ))
                                   (/.return $output))
@@ -772,7 +772,7 @@
                                            (all /.then
                                                 (/.set (list $inner_index) (/.+ (/.int +1) $inner_index))
                                                 (/.when (/.<= (/.int (.int expected_inner_iterations)) $inner_index)
-                                                        /.redo)
+                                                  /.redo)
                                                 (/.set (list $output) (/.+ $input $output))
                                                 ))
                                   (/.return $output))
@@ -981,7 +981,7 @@
            (expression (|>> (as Frac) (f.= (if ??? float/0 float/1)))
                        (|> (all /.then
                                 (/.when (/.bool ???)
-                                        (/.return (/.float float/0)))
+                                  (/.return (/.float float/0)))
                                 (/.return (/.float float/1)))
                            [(list)] (/.lambda {.#None})
                            (/.apply_lambda (list)))))
diff --git a/stdlib/source/test/lux/meta/type.lux b/stdlib/source/test/lux/meta/type.lux
index 226533dd1..3c6872d26 100644
--- a/stdlib/source/test/lux/meta/type.lux
+++ b/stdlib/source/test/lux/meta/type.lux
@@ -45,7 +45,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
@@ -364,7 +364,7 @@
                                      (random#each (|>> {.#Product}) pairG)
                                      (random#each (|>> {.#Function}) pairG)
                                      ))]
-       (case parameters
+       (when parameters
          0 un_parameterized
          _ (|> random.nat
                (random#each (|>> (n.% parameters) {.#Parameter}))
@@ -385,7 +385,7 @@
                   ($equivalence.spec /.equivalence (..random 0)))
            
            (do [! random.monad]
-             [anonymousT (random.only (|>> (pipe.case {.#Named _ _} false
+             [anonymousT (random.only (|>> (pipe.when {.#Named _ _} false
                                              _ true))
                                       (..random 0))
               symbol/0 ..symbol
@@ -401,7 +401,7 @@
              [size (|> random.nat (at ! each (n.% 3)))
               members (|> (..random 0)
                           (random.only (function (_ type)
-                                         (case type
+                                         (when type
                                            (^.or {.#Sum _} {.#Product _})
                                            false
 
@@ -430,7 +430,7 @@
                          full (/.applied (list Int) partial)]
                         (in (at /.equivalence = full {.#Product Bit Int}))))
                   (|> (/.applied (list Bit) Text)
-                      (pipe.case
+                      (pipe.when
                         {.#None}
                         true
                         
@@ -441,7 +441,7 @@
               members (monad.all ! (list.repeated size (..random 0)))
               extra (|> (..random 0)
                         (random.only (function (_ type)
-                                       (case type
+                                       (when type
                                          (^.or {.#Function _} {.#Apply _})
                                          false
 
@@ -462,7 +462,7 @@
              [size (|> random.nat (at ! each (|>> (n.% 3) ++)))
               body_type (|> (..random 0)
                             (random.only (function (_ type)
-                                           (case type
+                                           (when type
                                              (^.or {.#UnivQ _} {.#ExQ _})
                                              false
 
@@ -488,7 +488,7 @@
              [depth (|> random.nat (at ! each (|>> (n.% 3) ++)))
               element_type (|> (..random 0)
                                (random.only (function (_ type)
-                                              (case type
+                                              (when type
                                                 {.#Primitive name (list element_type)}
                                                 (not (text#= array.primitive name))
 
diff --git a/stdlib/source/test/lux/meta/type/check.lux b/stdlib/source/test/lux/meta/type/check.lux
index f6874ae5f..b6459169f 100644
--- a/stdlib/source/test/lux/meta/type/check.lux
+++ b/stdlib/source/test/lux/meta/type/check.lux
@@ -54,7 +54,7 @@
                                                      (random#each (|>> {.#Apply}) pairG)))
            random_id (let [random_id (random.either (random#each (|>> {.#Var}) random.nat)
                                                     (random#each (|>> {.#Ex}) random.nat))]
-                       (case num_vars
+                       (when num_vars
                          0 random_id
                          _ (random.either (random#each (|>> (n.% num_vars) (n.* 2) ++ {.#Parameter}) random.nat)
                                           random_id)))
@@ -74,7 +74,7 @@
 
 (def (valid_type? type)
   (-> Type Bit)
-  (case type
+  (when type
     {.#Primitive name params}
     (list.every? valid_type? params)
     
@@ -100,7 +100,7 @@
 (def comparison
   (Comparison (All (_ a) (/.Check a)))
   (function (_ == left right)
-    (case [(/.result /.fresh_context left) (/.result /.fresh_context right)]
+    (when [(/.result /.fresh_context left) (/.result /.fresh_context right)]
       [{try.#Success left} {try.#Success right}]
       (== left right)
 
@@ -141,7 +141,7 @@
          (do random.monad
            [expected (random.upper_case 10)]
            (_.coverage [/.failure]
-             (case (/.result /.fresh_context
+             (when (/.result /.fresh_context
                              (is (/.Check Any)
                                  (/.failure expected)))
                {try.#Success _} false
@@ -149,16 +149,16 @@
          (do random.monad
            [expected (random.upper_case 10)]
            (_.coverage [/.assertion]
-             (and (case (/.result /.fresh_context
+             (and (when (/.result /.fresh_context
                                   (is (/.Check Any)
                                       (/.assertion expected true)))
                     {try.#Success _} true
                     {try.#Failure actual} false)
-                  (case (/.result /.fresh_context (/.assertion expected false))
+                  (when (/.result /.fresh_context (/.assertion expected false))
                     {try.#Success _} false
                     {try.#Failure actual} (same? expected actual)))))
          (_.coverage [/.except]
-           (case (/.result /.fresh_context
+           (when (/.result /.fresh_context
                            (is (/.Check Any)
                                (/.except ..yolo [])))
              {try.#Success _} false
@@ -168,12 +168,12 @@
                               (and (|> (/.check  )
                                        (is (/.Check Any))
                                        (/.result /.fresh_context)
-                                       (pipe.case {try.#Failure error} (? error)
+                                       (pipe.when {try.#Failure error} (? error)
                                          {try.#Success _} false))
                                    (|> (/.check  )
                                        (is (/.Check Any))
                                        (/.result /.fresh_context)
-                                       (pipe.case {try.#Failure error} (? error)
+                                       (pipe.when {try.#Failure error} (? error)
                                          {try.#Success _} false)))))]
            (all _.and
                 (_.coverage [/.type_check_failed]
@@ -202,7 +202,7 @@
   (<| (_.for [/.Var])
       (all _.and
            (_.coverage [/.var]
-             (case (/.result /.fresh_context
+             (when (/.result /.fresh_context
                              (do /.monad
                                [[var_id var_type] /.var]
                                (in (//#= var_type {.#Var var_id}))))
@@ -211,7 +211,7 @@
            (do random.monad
              [nominal (random.upper_case 10)]
              (_.coverage [/.bind]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (do /.monad
                                  [[var_id var_type] /.var
                                   _ (/.bind {.#Primitive nominal (list)}
@@ -245,7 +245,7 @@
            (do random.monad
              [nominal (random.upper_case 10)]
              (_.coverage [/.cannot_rebind_var]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (do /.monad
                                  [[var_id var_type] /.var
                                   _ (/.bind {.#Primitive nominal (list)}
@@ -261,7 +261,7 @@
              [nominal (random.upper_case 10)
               var_id random.nat]
              (_.coverage [/.unknown_type_var]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (/.bind {.#Primitive nominal (list)}
                                        var_id))
                  {try.#Success _}
@@ -277,7 +277,7 @@
                           [[var_id var_type] /.var]
                           (/.peek var_id))
                         (/.result /.fresh_context)
-                        (pipe.case {try.#Success {.#None}} true
+                        (pipe.when {try.#Success {.#None}} true
                           _ false))
                     (|> (do /.monad
                           [[var_id var/0] /.var
@@ -285,14 +285,14 @@
                            _ (/.check var/0 var/1)]
                           (/.peek var_id))
                         (/.result /.fresh_context)
-                        (pipe.case {try.#Success {.#None}} true
+                        (pipe.when {try.#Success {.#None}} true
                           _ false))
                     (|> (do /.monad
                           [[var_id var_type] /.var
                            _ (/.bind expected var_id)]
                           (/.peek var_id))
                         (/.result /.fresh_context)
-                        (pipe.case {try.#Success {.#Some actual}}
+                        (pipe.when {try.#Success {.#Some actual}}
                           (same? expected actual)
                           
                           _
@@ -301,7 +301,7 @@
              [nominal (random.upper_case 10)
               .let [expected {.#Primitive nominal (list)}]]
              (_.coverage [/.read]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (do /.monad
                                  [[var_id var_type] /.var
                                   _ (/.bind expected var_id)]
@@ -315,7 +315,7 @@
              [nominal (random.upper_case 10)
               .let [expected {.#Primitive nominal (list)}]]
              (_.coverage [/.unbound_type_var]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (do /.monad
                                  [[var_id var_type] /.var]
                                  (/.read var_id)))
@@ -334,13 +334,13 @@
               (n.= 0 (the .#ex_counter /.fresh_context))
               (list.empty? (the .#var_bindings /.fresh_context))))
        (_.coverage [/.context]
-         (and (case (/.result /.fresh_context /.context)
+         (and (when (/.result /.fresh_context /.context)
                 {try.#Success actual}
                 (same? /.fresh_context actual)
                 
                 {try.#Failure error}
                 false)
-              (case (/.result /.fresh_context
+              (when (/.result /.fresh_context
                               (do /.monad
                                 [_ /.var]
                                 /.context))
@@ -352,7 +352,7 @@
                 {try.#Failure error}
                 false)))
        (_.coverage [/.existential]
-         (case (/.result /.fresh_context
+         (when (/.result /.fresh_context
                          (do /.monad
                            [_ /.existential]
                            /.context))
@@ -368,7 +368,7 @@
 (def succeeds?
   (All (_ a) (-> (/.Check a) Bit))
   (|>> (/.result /.fresh_context)
-       (pipe.case {try.#Success _}
+       (pipe.when {try.#Success _}
          true
 
          {try.#Failure error}
@@ -457,7 +457,7 @@
 (def (verdict check)
   (All (_ _) (-> (/.Check _) (/.Check Bit)))
   (function (_ context)
-    {try.#Success [context (case (check context)
+    {try.#Success [context (when (check context)
                              {try.#Success _}
                              true
 
@@ -889,7 +889,7 @@
            (do random.monad
              [expected random.nat]
              (_.coverage [/.result]
-               (case (/.result /.fresh_context
+               (when (/.result /.fresh_context
                                (at /.monad in expected))
                  {try.#Success actual} (same? expected actual)
                  {try.#Failure error} false)))
diff --git a/stdlib/source/test/lux/meta/type/dynamic.lux b/stdlib/source/test/lux/meta/type/dynamic.lux
index 78382883f..d14bbbb19 100644
--- a/stdlib/source/test/lux/meta/type/dynamic.lux
+++ b/stdlib/source/test/lux/meta/type/dynamic.lux
@@ -26,21 +26,21 @@
         [expected random.nat]
         (all _.and
              (_.coverage [/.dynamic /.static]
-               (case (/.static Nat (/.dynamic expected))
+               (when (/.static Nat (/.dynamic expected))
                  {try.#Success actual}
                  (n.= expected actual)
                  
                  {try.#Failure _}
                  false))
              (_.coverage [/.wrong_type]
-               (case (/.static Text (/.dynamic expected))
+               (when (/.static Text (/.dynamic expected))
                  {try.#Success actual}
                  false
                  
                  {try.#Failure error}
                  (exception.match? /.wrong_type error)))
              (_.coverage [/.format]
-               (case (/.format (/.dynamic expected))
+               (when (/.format (/.dynamic expected))
                  {try.#Success actual}
                  (text#= (%.nat expected) actual)
                  
diff --git a/stdlib/source/test/lux/meta/type/refinement.lux b/stdlib/source/test/lux/meta/type/refinement.lux
index 845c878fd..2921ff8c2 100644
--- a/stdlib/source/test/lux/meta/type/refinement.lux
+++ b/stdlib/source/test/lux/meta/type/refinement.lux
@@ -40,7 +40,7 @@
              (_.for [/.Refiner]
                     (all _.and
                          (_.coverage [/.refiner]
-                           (case (/.refiner predicate raw)
+                           (when (/.refiner predicate raw)
                              {.#Some refined}
                              (predicate raw)
                              
diff --git a/stdlib/source/test/lux/meta/type/resource.lux b/stdlib/source/test/lux/meta/type/resource.lux
index 25c44d81a..33859dd4e 100644
--- a/stdlib/source/test/lux/meta/type/resource.lux
+++ b/stdlib/source/test/lux/meta/type/resource.lux
@@ -164,7 +164,7 @@
       [[_ _ exception] (meta.export exception)]
       (function (_ compiler)
         {.#Right [compiler
-                  (list (code.bit (case ((expansion.single to_expand) compiler)
+                  (list (code.bit (when ((expansion.single to_expand) compiler)
                                     {try.#Success _}
                                     false
                                     
diff --git a/stdlib/source/test/lux/meta/version.lux b/stdlib/source/test/lux/meta/version.lux
index 999e2f2e1..2182f3197 100644
--- a/stdlib/source/test/lux/meta/version.lux
+++ b/stdlib/source/test/lux/meta/version.lux
@@ -27,7 +27,7 @@
 (def failure
   (syntax (_ [it .any])
     (function (_ lux)
-      (case (expansion.complete it lux)
+      (when (expansion.complete it lux)
         {try.#Failure error}
         {try.#Success [lux (list (code.text error))]}
         
diff --git a/stdlib/source/test/lux/program.lux b/stdlib/source/test/lux/program.lux
index 62ab2204e..a4382595d 100644
--- a/stdlib/source/test/lux/program.lux
+++ b/stdlib/source/test/lux/program.lux
@@ -29,7 +29,7 @@
 
 (def !expect
   (template (_  )
-    [(case 
+    [(when 
        
        true
        
@@ -122,7 +122,7 @@
                                      inputs)]
                         (list#= inputs
                                 (as (List Text) (io.run! outcome))))
-                      (case (try ((is /.Program
+                      (when (try ((is /.Program
                                       (/.program [arg/0 \\parser.any
                                                   arg/1 \\parser.any
                                                   arg/2 \\parser.any
diff --git a/stdlib/source/test/lux/world/environment.lux b/stdlib/source/test/lux/world/environment.lux
index c2a9ac384..df434f657 100644
--- a/stdlib/source/test/lux/world/environment.lux
+++ b/stdlib/source/test/lux/world/environment.lux
@@ -54,7 +54,7 @@
            (do random.monad
              [property (random.alphabetic 1)]
              (_.coverage [\\parser.unknown_property]
-               (case (\\parser.result (\\parser.property property) \\parser.empty)
+               (when (\\parser.result (\\parser.property property) \\parser.empty)
                  {try.#Success _}
                  false
                  
@@ -104,7 +104,7 @@
                  (|> unknown
                      (at it variable)
                      io.run!
-                     (pipe.case {try.#Success _}
+                     (pipe.when {try.#Success _}
                        false
                        
                        {try.#Failure error}
diff --git a/stdlib/source/test/lux/world/file.lux b/stdlib/source/test/lux/world/file.lux
index 3eec4fa19..477b09110 100644
--- a/stdlib/source/test/lux/world/file.lux
+++ b/stdlib/source/test/lux/world/file.lux
@@ -41,7 +41,7 @@
   (-> (Atom Disk) (-> /.Path (IO Bit)))
   (do io.monad
     [disk (atom.read! disk)]
-    (in (case (dictionary.value @ disk)
+    (in (when (dictionary.value @ disk)
           {.#None} false
           {.#Some {.#Left _}} true
           {.#Some {.#Right _}} false))))
@@ -50,7 +50,7 @@
   (-> (Atom Disk) (-> /.Path (IO Bit)))
   (do io.monad
     [disk (atom.read! disk)]
-    (in (case (dictionary.value @ disk)
+    (in (when (dictionary.value @ disk)
           {.#None} false
           {.#Some {.#Left _}} false
           {.#Some {.#Right _}} true))))
@@ -61,7 +61,7 @@
       (-> /.Path (IO (Try Any))))
   (do [! io.monad]
     [disk' (atom.read! disk)]
-    (case (dictionary.value @ disk')
+    (when (dictionary.value @ disk')
       {.#Some {.#Right siblings}}
       (do !
         [_ (atom.compare_and_swap! disk' (dictionary.has @ {.#Right (alert siblings)} disk') disk)]
@@ -75,12 +75,12 @@
   (do [! io.monad]
     [now instant.now
      disk' (atom.read! disk)]
-    (case (dictionary.value @ disk')
+    (when (dictionary.value @ disk')
       (^.or {.#None}
             {.#Some {.#Left _}})
       (do !
         [_ (atom.compare_and_swap! disk' (dictionary.has @ {.#Left [now it]} disk') disk)]
-        (case (/.parent fs @)
+        (when (/.parent fs @)
           {.#Some parent}
           (alert_parent! disk (|>> (list.partial @)) parent)
 
@@ -94,7 +94,7 @@
   (-> (Atom Disk) (-> /.Path (IO (Try Binary))))
   (do io.monad
     [disk (atom.read! disk)]
-    (in (case (dictionary.value @ disk)
+    (in (when (dictionary.value @ disk)
           {.#Some {.#Left [_ it]}}
           {try.#Success it}
 
@@ -106,7 +106,7 @@
       (-> /.Path (IO (Try Any))))
   (do [! io.monad]
     [disk' (atom.read! disk)]
-    (case (dictionary.value @ disk')
+    (when (dictionary.value @ disk')
       {.#Some {.#Right children}}
       (if (list.empty? children)
         (do !
@@ -117,7 +117,7 @@
       {.#Some {.#Left [_ data]}}
       (do !
         [_ (atom.compare_and_swap! disk' (dictionary.lacks @ disk') disk)]
-        (case (/.parent fs @)
+        (when (/.parent fs @)
           {.#Some parent}
           (alert_parent! disk (list.only (|>> (text#= @) not)) parent)
 
@@ -144,7 +144,7 @@
      (def (file_size @)
        (do [! io.monad]
          [disk (atom.read! disk)]
-         (in (case (dictionary.value @ disk)
+         (in (when (dictionary.value @ disk)
                {.#Some {.#Left [_ it]}}
                {try.#Success (binary.size it)}
 
@@ -153,7 +153,7 @@
      (def (last_modified @)
        (do [! io.monad]
          [disk (atom.read! disk)]
-         (in (case (dictionary.value @ disk)
+         (in (when (dictionary.value @ disk)
                {.#Some {.#Left [it _]}}
                {try.#Success it}
 
@@ -162,7 +162,7 @@
      (def (can_execute? @)
        (do [! io.monad]
          [disk (atom.read! disk)]
-         (in (case (dictionary.value @ disk)
+         (in (when (dictionary.value @ disk)
                {.#Some {.#Left _}}
                {try.#Success false}
 
@@ -172,11 +172,11 @@
      (def (make_directory @)
        (do [! io.monad]
          [disk' (atom.read! disk)]
-         (case (dictionary.value @ disk')
+         (when (dictionary.value @ disk')
            {.#None}
            (do !
              [_ (atom.compare_and_swap! disk' (dictionary.has @ {.#Right (list)} disk') disk)]
-             (case (/.parent mock @)
+             (when (/.parent mock @)
                {.#Some parent}
                (alert_parent! disk (|>> (list.partial @)) parent)
 
@@ -188,7 +188,7 @@
      (def (directory_files @)
        (do [! io.monad]
          [disk' (atom.read! disk)]
-         (case (dictionary.value @ disk')
+         (when (dictionary.value @ disk')
            {.#Some {.#Right children}}
            (|> children
                (monad.only ! (..file? disk))
@@ -199,7 +199,7 @@
      (def (sub_directories @)
        (do [! io.monad]
          [disk' (atom.read! disk)]
-         (case (dictionary.value @ disk')
+         (when (dictionary.value @ disk')
            {.#Some {.#Right children}}
            (|> children
                (monad.only ! (..directory? disk))
@@ -211,7 +211,7 @@
        (do [! io.monad]
          [now instant.now
           disk' (atom.read! disk)]
-         (case (dictionary.value @ disk')
+         (when (dictionary.value @ disk')
            {.#None}
            (..write mock disk @ it)
            
@@ -227,7 +227,7 @@
      (def (modify @ it)
        (do [! io.monad]
          [disk' (atom.read! disk)]
-         (case (dictionary.value @ disk')
+         (when (dictionary.value @ disk')
            {.#Some {.#Left [_ data]}}
            (do !
              [_ (atom.compare_and_swap! disk' (dictionary.has @ {.#Left [it data]} disk') disk)]
@@ -258,7 +258,7 @@
                    [.let [fs (/.mock /)]
                     ? (at fs delete file)]
                    (unit.coverage [/.cannot_delete]
-                     (case ?
+                     (when ?
                        {try.#Failure error}
                        (exception.match? /.cannot_delete error)
 
@@ -268,7 +268,7 @@
                    [.let [fs (/.mock /)]
                     ? (at fs read file)]
                    (unit.coverage [/.cannot_find_file]
-                     (case ?
+                     (when ?
                        {try.#Failure error}
                        (exception.match? /.cannot_find_file error)
 
@@ -279,7 +279,7 @@
                     ?/0 (at fs directory_files file)
                     ?/1 (at fs sub_directories file)]
                    (unit.coverage [/.cannot_find_directory]
-                     (case [?/0 ?/1]
+                     (when [?/0 ?/1]
                        [{try.#Failure error/0} {try.#Failure error/1}]
                        (and (exception.match? /.cannot_find_directory error/0)
                             (exception.match? /.cannot_find_directory error/1))
diff --git a/stdlib/source/test/lux/world/file/watch.lux b/stdlib/source/test/lux/world/file/watch.lux
index 73f7755ca..e8ce8182e 100644
--- a/stdlib/source/test/lux/world/file/watch.lux
+++ b/stdlib/source/test/lux/world/file/watch.lux
@@ -77,13 +77,13 @@
                [?concern (at watcher concern directory)
                 ?stop (at watcher stop directory)]
                (unit.coverage [/.not_being_watched]
-                 (and (case ?concern
+                 (and (when ?concern
                         {try.#Failure error}
                         (exception.match? /.not_being_watched error)
 
                         {try.#Success _}
                         false)
-                      (case ?stop
+                      (when ?stop
                         {try.#Failure error}
                         (exception.match? /.not_being_watched error)
 
@@ -106,7 +106,7 @@
            (//.make_file async.monad fs (binary.empty 0) expected_path))
      poll/pre (at watcher poll [])
      poll/post (at watcher poll [])]
-    (in (and (case poll/pre
+    (in (and (when poll/pre
                (list [concern actual_path])
                (and (text#= expected_path actual_path)
                     (and (/.creation? concern)
@@ -124,7 +124,7 @@
      _ (at fs write expected_path data)
      poll/2 (at watcher poll [])
      poll/2' (at watcher poll [])]
-    (in (and (case poll/2
+    (in (and (when poll/2
                (list [concern actual_path])
                (and (text#= expected_path actual_path)
                     (and (not (/.creation? concern))
@@ -141,7 +141,7 @@
     [_ (at fs delete expected_path)
      poll/3 (at watcher poll [])
      poll/3' (at watcher poll [])]
-    (in (and (case poll/3
+    (in (and (when poll/3
                (list [concern actual_path])
                (and (not (/.creation? concern))
                     (not (/.modification? concern))
@@ -193,7 +193,7 @@
              (in (do async.monad
                    [started? (at watcher start /.all directory)]
                    (unit.coverage [/.cannot_poll_a_non_existent_directory]
-                     (case started?
+                     (when started?
                        {try.#Success _}
                        false
                        
diff --git a/stdlib/source/test/lux/world/net/http/client.lux b/stdlib/source/test/lux/world/net/http/client.lux
index 01bd03616..aa8ed3b58 100644
--- a/stdlib/source/test/lux/world/net/http/client.lux
+++ b/stdlib/source/test/lux/world/net/http/client.lux
@@ -37,7 +37,7 @@
         (! Bit)))
   (do !
     [response response]
-    (case response
+    (when response
       {try.#Success response}
       (|> response
           product.right
@@ -72,7 +72,7 @@
          .let [mock (is (/.Client IO)
                         (implementation
                          (def (request method url headers data)
-                           (io.io (let [value (case method
+                           (io.io (let [value (when method
                                                 {//.#Post} on_post
                                                 {//.#Get} on_get
                                                 {//.#Put} on_put
diff --git a/stdlib/source/test/lux/world/shell.lux b/stdlib/source/test/lux/world/shell.lux
index 8b3da3a10..ce6b1b984 100644
--- a/stdlib/source/test/lux/world/shell.lux
+++ b/stdlib/source/test/lux/world/shell.lux
@@ -105,7 +105,7 @@
                                failure (at process fail [])
                                wrote! (do !
                                         [write (at process write input)]
-                                        (in {try.#Success (case write
+                                        (in {try.#Success (when write
                                                             {try.#Success _}
                                                             false
                                                             
@@ -113,7 +113,7 @@
                                                             (text#= input write))}))
                                destroyed! (do !
                                             [destroy (at process destroy [])]
-                                            (in {try.#Success (case destroy
+                                            (in {try.#Success (when destroy
                                                                 {try.#Success _}
                                                                 false
                                                                 
diff --git a/stdlib/source/test/lux/world/time.lux b/stdlib/source/test/lux/world/time.lux
index 6e3bbff5b..4ca58afca 100644
--- a/stdlib/source/test/lux/world/time.lux
+++ b/stdlib/source/test/lux/world/time.lux
@@ -76,7 +76,7 @@
                                 (text.prefix )
                                 (text.suffix )
                                 (at /.codec decoded)
-                                (pipe.case
+                                (pipe.when
                                   {try.#Success _} true
                                   {try.#Failure error} false))
                             
@@ -86,7 +86,7 @@
                                 (text.prefix )
                                 (text.suffix )
                                 (at /.codec decoded)
-                                (pipe.case
+                                (pipe.when
                                   {try.#Success _}
                                   false
                                   
@@ -104,7 +104,7 @@
                    %.nat
                    (format "00:00:00.")
                    (at /.codec decoded)
-                   (pipe.case
+                   (pipe.when
                      {try.#Success _} true
                      {try.#Failure error} false)))
              ))))
@@ -129,7 +129,7 @@
                        (try#each (at /.equivalence = expected))
                        (try.else false)))
                  (_.coverage [/.time_exceeds_a_day]
-                   (case (/.of_millis out_of_bounds)
+                   (when (/.of_millis out_of_bounds)
                      {try.#Success _}
                      false
                      
diff --git a/stdlib/source/test/lux/world/time/date.lux b/stdlib/source/test/lux/world/time/date.lux
index e6887f9e0..3dd22343b 100644
--- a/stdlib/source/test/lux/world/time/date.lux
+++ b/stdlib/source/test/lux/world/time/date.lux
@@ -50,7 +50,7 @@
            (do random.monad
              [expected random.date]
              (_.coverage [/.invalid_day]
-               (case (/.date (/.year expected)
+               (when (/.date (/.year expected)
                              (/.month expected)
                              (n.+ 31 (/.day_of_month expected)))
                  {try.#Failure error}
@@ -87,7 +87,7 @@
                                   "-" (%.nat month)
                                   "-" (%.nat day))]]
              (_.coverage [/.invalid_month]
-               (case (.result /.parser input)
+               (when (.result /.parser input)
                  {try.#Failure error}
                  (exception.match? /.invalid_month error)
                  
diff --git a/stdlib/source/test/lux/world/time/day.lux b/stdlib/source/test/lux/world/time/day.lux
index f69727234..c6471ffae 100644
--- a/stdlib/source/test/lux/world/time/day.lux
+++ b/stdlib/source/test/lux/world/time/day.lux
@@ -61,7 +61,7 @@
              (do random.monad
                [not_a_day (random.upper_case 1)]
                (_.coverage [/.not_a_day_of_the_week]
-                 (case (at /.codec decoded not_a_day)
+                 (when (at /.codec decoded not_a_day)
                    {try.#Failure error}
                    (exception.match? /.not_a_day_of_the_week error)
                    
@@ -74,7 +74,7 @@
                    (try#each (at /.equivalence = expected))
                    (try.else false)))
              (_.coverage [/.invalid_day]
-               (case (/.by_number invalid)
+               (when (/.by_number invalid)
                  {try.#Failure error}
                  (exception.match? /.invalid_day error)
                  
diff --git a/stdlib/source/test/lux/world/time/instant.lux b/stdlib/source/test/lux/world/time/instant.lux
index cebba07ff..32b4c71f3 100644
--- a/stdlib/source/test/lux/world/time/instant.lux
+++ b/stdlib/source/test/lux/world/time/instant.lux
@@ -98,7 +98,7 @@
                       (apply duration.inverse day#pred 6)
                       (apply duration.inverse day#pred 7)))))
            (_.coverage [/.now]
-             (case (try (io.run! /.now))
+             (when (try (io.run! /.now))
                {try.#Success _}
                true
                
diff --git a/stdlib/source/test/lux/world/time/month.lux b/stdlib/source/test/lux/world/time/month.lux
index e7b5f09a2..29117b8d3 100644
--- a/stdlib/source/test/lux/world/time/month.lux
+++ b/stdlib/source/test/lux/world/time/month.lux
@@ -65,7 +65,7 @@
                         (try#each (at /.equivalence = expected))
                         (try.else false)))
                   (_.coverage [/.invalid_month]
-                    (case (/.by_number invalid)
+                    (when (/.by_number invalid)
                       {try.#Failure error}
                       (exception.match? /.invalid_month error)
                       
@@ -93,7 +93,7 @@
                   (do random.monad
                     [not_a_month (random.upper_case 1)]
                     (_.coverage [/.not_a_month_of_the_year]
-                      (case (at /.codec decoded not_a_month)
+                      (when (at /.codec decoded not_a_month)
                         {try.#Failure error}
                         (exception.match? /.not_a_month_of_the_year error)
                         
diff --git a/stdlib/source/test/lux/world/time/year.lux b/stdlib/source/test/lux/world/time/year.lux
index 32c19dccf..ec4638abd 100644
--- a/stdlib/source/test/lux/world/time/year.lux
+++ b/stdlib/source/test/lux/world/time/year.lux
@@ -49,14 +49,14 @@
              (all _.and
                   (_.coverage [/.year]
                     (bit#= (i.= +0 expected)
-                           (case (/.year expected)
+                           (when (/.year expected)
                              {try.#Success _}
                              false
 
                              {try.#Failure _}
                              true)))
                   (_.coverage [/.value]
-                    (case (/.year expected)
+                    (when (/.year expected)
                       {try.#Success year}
                       (i.= expected (/.value year))
 
@@ -64,7 +64,7 @@
                       (i.= +0 expected)))
                   ))
            (_.coverage [/.there_is_no_year_0]
-             (case (/.year +0)
+             (when (/.year +0)
                {try.#Success _}
                false
 
-- 
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