Fixed directive extensions for Lux/Python.

40 files changed, 714 insertions, 378 deletions

diff --git a/stdlib/source/library/lux.lux b/stdlib/source/library/lux.lux
index 7ddfa427f..75575ebe4 100644
--- a/stdlib/source/library/lux.lux
+++ b/stdlib/source/library/lux.lux
@@ -3718,13 +3718,6 @@
                          cases)]
     output))
 
-(def: (on_either f x1 x2)
-  (All (_ a b)
-    (-> (-> a (Maybe b)) a a (Maybe b)))
-  (case (f x1)
-    {#None}   (f x2)
-    {#Some y} {#Some y}))
-
 (def: (in_env name state)
   (-> Text Lux (Maybe Type))
   (case state
@@ -3738,14 +3731,13 @@
                      [..#name _
                       ..#inner _
                       ..#locals [..#counter _ ..#mappings locals]
-                      ..#captured [..#counter _ ..#mappings closure]]
-                     (on_either (list#one (: (-> [Text [Type Any]] (Maybe Type))
-                                             (function (_ [bname [type _]])
-                                               (if (text#= name bname)
-                                                 {#Some type}
-                                                 {#None}))))
-                                (: (List [Text [Type Any]]) locals)
-                                (: (List [Text [Type Any]]) closure)))))
+                      ..#captured _]
+                     (list#one (: (-> [Text [Type Any]] (Maybe Type))
+                                  (function (_ [bname [type _]])
+                                    (if (text#= name bname)
+                                      {#Some type}
+                                      {#None})))
+                               locals))))
               scopes)))
 
 (def: (definition_type name state)
@@ -3839,24 +3831,25 @@
     [.let [[module name] full_name]
      current_module current_module_name]
     (function (_ compiler)
-      (let [temp (if (text#= "" module)
-                   (case (in_env name compiler)
-                     {#Some struct_type}
-                     {#Right [compiler struct_type]}
+      (let [temp (: (Either Text [Lux Type])
+                    (if (text#= "" module)
+                      (case (in_env name compiler)
+                        {#Some struct_type}
+                        {#Right [compiler struct_type]}
 
-                     _
-                     (case (definition_type [current_module name] compiler)
-                       {#Some struct_type}
-                       {#Right [compiler struct_type]}
+                        _
+                        (case (definition_type [current_module name] compiler)
+                          {#Some struct_type}
+                          {#Right [compiler struct_type]}
 
-                       _
-                       {#Left ($_ text#composite "Unknown var: " (symbol#encoded full_name))}))
-                   (case (definition_type full_name compiler)
-                     {#Some struct_type}
-                     {#Right [compiler struct_type]}
+                          _
+                          {#Left ($_ text#composite "Unknown var: " (symbol#encoded full_name))}))
+                      (case (definition_type full_name compiler)
+                        {#Some struct_type}
+                        {#Right [compiler struct_type]}
 
-                     _
-                     {#Left ($_ text#composite "Unknown var: " (symbol#encoded full_name))}))]
+                        _
+                        {#Left ($_ text#composite "Unknown var: " (symbol#encoded full_name))})))]
         (case temp
           {#Right [compiler {#Var type_id}]}
           (let [[..#info _ ..#source _ ..#current_module _ ..#modules _
@@ -4708,30 +4701,6 @@
     _
     (failure (..wrong_syntax_error [..prelude_module "symbol"]))))
 
-(def: (scope_type_vars state)
-  (Meta (List Nat))
-  (case state
-    [..#info info ..#source    source ..#current_module _   ..#modules modules
-     ..#scopes scopes ..#type_context types    ..#host    host
-     ..#seed seed ..#expected  expected ..#location  location ..#extensions extensions
-     ..#scope_type_vars scope_type_vars ..#eval _eval]
-    {#Right [state scope_type_vars]}))
-
-(macro: .public (:parameter tokens)
-  (case tokens
-    (^ (list [_ {#Nat idx}]))
-    (do meta_monad
-      [stvs ..scope_type_vars]
-      (case (..item idx (list#reversed stvs))
-        {#Some var_id}
-        (in (list (` {.#Ex (~ (nat$ var_id))})))
-
-        {#None}
-        (failure (text#composite "Indexed-type does not exist: " (nat#encoded idx)))))
-
-    _
-    (failure (..wrong_syntax_error (symbol ..$)))))
-
 (def: .public (same? reference sample)
   (All (_ a)
     (-> a a Bit))
@@ -4927,6 +4896,32 @@
       _
       (failure (..wrong_syntax_error (symbol ..for))))))
 
+... TODO: Delete "scope_type_vars" (including the #scope_type_vars Lux state) and ":parameter" ASAP.
+(for ["{old}" (as_is (def: (scope_type_vars state)
+                       (Meta (List Nat))
+                       (case state
+                         [..#info info ..#source    source ..#current_module _   ..#modules modules
+                          ..#scopes scopes ..#type_context types    ..#host    host
+                          ..#seed seed ..#expected  expected ..#location  location ..#extensions extensions
+                          ..#scope_type_vars scope_type_vars ..#eval _eval]
+                         {#Right [state scope_type_vars]}))
+
+                     (macro: .public (:parameter tokens)
+                       (case tokens
+                         (^ (list [_ {#Nat idx}]))
+                         (do meta_monad
+                           [stvs ..scope_type_vars]
+                           (case (..item idx (list#reversed stvs))
+                             {#Some var_id}
+                             (in (list (` {.#Ex (~ (nat$ var_id))})))
+
+                             {#None}
+                             (failure (text#composite "Indexed-type does not exist: " (nat#encoded idx)))))
+
+                         _
+                         (failure (..wrong_syntax_error (symbol ..$))))))]
+     (as_is))
+
 (macro: .public (using _imports)
   (do meta_monad
     [current_module ..current_module_name
diff --git a/stdlib/source/library/lux/abstract/enum.lux b/stdlib/source/library/lux/abstract/enum.lux
index 45026abc1..f136fc92d 100644
--- a/stdlib/source/library/lux/abstract/enum.lux
+++ b/stdlib/source/library/lux/abstract/enum.lux
@@ -1,8 +1,8 @@
 (.using
-  [library
-   [lux "*"]]
-  [//
-   ["[0]" order {"+" Order}]])
+ [library
+  [lux "*"]]
+ [//
+  ["[0]" order {"+" Order}]])
 
 (type: .public (Enum e)
   (Interface
@@ -12,14 +12,15 @@
 
 (def: .public (range enum from to)
   (All (_ a) (-> (Enum a) a a (List a)))
-  (let [(^open "[0]") enum]
+  (let [(^open "/#[0]") enum]
     (loop [end to
-           output {.#End}]
-      (cond (< end from)
-            (again (pred end) {.#Item end output})
+           output (`` (: (List (~~ (:of from)))
+                         {.#End}))]
+      (cond (/#< end from)
+            (again (/#pred end) {.#Item end output})
 
-            (< from end)
-            (again (succ end) {.#Item end output})
+            (/#< from end)
+            (again (/#succ end) {.#Item end output})
 
             ... (= end from)
             {.#Item end output}))))
diff --git a/stdlib/source/library/lux/control/lazy.lux b/stdlib/source/library/lux/control/lazy.lux
index 9e59da7dc..8d3c877d8 100644
--- a/stdlib/source/library/lux/control/lazy.lux
+++ b/stdlib/source/library/lux/control/lazy.lux
@@ -1,28 +1,33 @@
 (.using
-  [library
-   [lux "*"
-    [abstract
-     [functor {"+" Functor}]
-     [apply {"+" Apply}]
-     [monad {"+" Monad do}]
-     [equivalence {"+" Equivalence}]]
-    [control
-     ["[0]" io]
-     [parser
-      ["<[0]>" code]]
-     [concurrency
-      ["[0]" atom]]]
-    [macro {"+" with_symbols}
-     [syntax {"+" syntax:}]]
-    [type
-     abstract]]])
+ [library
+  [lux "*"
+   [abstract
+    [functor {"+" Functor}]
+    [apply {"+" Apply}]
+    [monad {"+" Monad do}]
+    [equivalence {"+" Equivalence}]]
+   [control
+    ["[0]" io]
+    [parser
+     ["<[0]>" code]]
+    [concurrency
+     ["[0]" atom]]]
+   [macro {"+" with_symbols}
+    [syntax {"+" syntax:}]]
+   [type {"+" :sharing}
+    abstract]]])
 
 (abstract: .public (Lazy a)
   (-> [] a)
 
   (def: (lazy' generator)
     (All (_ a) (-> (-> [] a) (Lazy a)))
-    (let [cache (atom.atom {.#None})]
+    (let [cache (atom.atom (:sharing [a]
+                                     (-> [] a)
+                                     generator
+
+                                     (Maybe a)
+                                     {.#None}))]
       (:abstraction (function (_ _)
                       (case (io.run! (atom.read! cache))
                         {.#Some value}
diff --git a/stdlib/source/library/lux/data/collection/array.lux b/stdlib/source/library/lux/data/collection/array.lux
index ea16cddfc..437c80bfa 100644
--- a/stdlib/source/library/lux/data/collection/array.lux
+++ b/stdlib/source/library/lux/data/collection/array.lux
@@ -275,10 +275,10 @@
   Nat
   (-- 0))
 
-(def: (list|-default array)
-  (All (_ a) (-> (Array a) (List a)))
+(def: (list|-default array empty)
+  (All (_ a) (-> (Array a) (List a) (List a)))
   (loop [idx (-- (size array))
-         output {.#End}]
+         output empty]
     (case idx
       (^ (static ..underflow))
       output
@@ -295,7 +295,8 @@
 (def: (list|+default default array)
   (All (_ a) (-> a (Array a) (List a)))
   (loop [idx (-- (size array))
-         output {.#End}]
+         output (`` (: (List (~~ (:of default)))
+                       {.#End}))]
     (case idx
       (^ (static ..underflow))
       output
@@ -312,7 +313,7 @@
     (list|+default default array)
     
     {.#None}
-    (list|-default array)))
+    (list|-default array {.#End})))
 
 (implementation: .public (equivalence (^open ",#[0]"))
   (All (_ a) (-> (Equivalence a) (Equivalence (Array a))))
diff --git a/stdlib/source/library/lux/data/collection/dictionary/ordered.lux b/stdlib/source/library/lux/data/collection/dictionary/ordered.lux
index 083ad161c..7437962f6 100644
--- a/stdlib/source/library/lux/data/collection/dictionary/ordered.lux
+++ b/stdlib/source/library/lux/data/collection/dictionary/ordered.lux
@@ -475,9 +475,6 @@
   (let [(^open "_#[0]") (value@ #&order dict)
         [?root found?] (loop [?root (value@ #root dict)]
                          (case ?root
-                           {.#None}
-                           [{.#None} #0]
-
                            {.#Some root}
                            (let [root_key (value@ #key root)
                                  root_val (value@ #value root)]
@@ -514,6 +511,9 @@
                                         #0])
                                      )))
                                ))
+
+                           {.#None}
+                           [{.#None} #0]
                            ))]
     (case ?root
       {.#None}
diff --git a/stdlib/source/library/lux/data/collection/list.lux b/stdlib/source/library/lux/data/collection/list.lux
index 28f4d3db7..e5130f985 100644
--- a/stdlib/source/library/lux/data/collection/list.lux
+++ b/stdlib/source/library/lux/data/collection/list.lux
@@ -382,7 +382,10 @@
                             (if (< x x')
                               [{.#Item x' pre} post]
                               [pre {.#Item x' post}]))
-                          [(list) (list)]
+                          (`` [(: (~~ (:of xs))
+                                  (list))
+                               (: (~~ (:of xs))
+                                  (list))])
                           xs')]
       ($_ composite (sorted < pre) (list x) (sorted < post)))))
 
diff --git a/stdlib/source/library/lux/data/collection/sequence.lux b/stdlib/source/library/lux/data/collection/sequence.lux
index 07ebeba76..746654c57 100644
--- a/stdlib/source/library/lux/data/collection/sequence.lux
+++ b/stdlib/source/library/lux/data/collection/sequence.lux
@@ -224,10 +224,8 @@
             ... If so, a brand-new root must be established, that is
             ... 1-level taller.
             (|> sequence
-                (with@ #root (|> (for [@.old
-                                       (: (Hierarchy (:parameter 0))
-                                          (empty_hierarchy []))]
-                                      (empty_hierarchy []))
+                (with@ #root (|> (`` (: (Hierarchy (~~ (:of val)))
+                                        (empty_hierarchy [])))
                                  (array.write! 0 {#Hierarchy (value@ #root sequence)})
                                  (array.write! 1 (..path (value@ #level sequence) (value@ #tail sequence)))))
                 (revised@ #level level_up))
@@ -293,10 +291,9 @@
       {try.#Success (if (n.< (tail_off sequence_size) idx)
                       (revised@ #root (hierarchy#has (value@ #level sequence) idx val)
                                 sequence)
-                      (revised@ #tail (for [@.old
-                                            (: (-> (Base (:parameter 0)) (Base (:parameter 0)))
-                                               (|>> array.clone (array.write! (branch_idx idx) val)))]
-                                           (|>> array.clone (array.write! (branch_idx idx) val)))
+                      (revised@ #tail (`` (: (-> (Base (~~ (:of val)))
+                                                 (Base (~~ (:of val))))
+                                             (|>> array.clone (array.write! (branch_idx idx) val))))
                                 sequence))}
       (exception.except ..index_out_of_bounds [sequence idx]))))
 
diff --git a/stdlib/source/library/lux/data/collection/tree/finger.lux b/stdlib/source/library/lux/data/collection/tree/finger.lux
index 270623c6e..7c8a244b1 100644
--- a/stdlib/source/library/lux/data/collection/tree/finger.lux
+++ b/stdlib/source/library/lux/data/collection/tree/finger.lux
@@ -15,8 +15,8 @@
   (Record
    [#monoid (Monoid t)
     #tag t
-    #root (Or v
-              [(Tree @ t v) (Tree @ t v)])])
+    #root (Either v
+                  [(Tree @ t v) (Tree @ t v)])])
 
   (type: .public (Builder @ t)
     (Interface
@@ -45,13 +45,13 @@
       (:abstraction
        [#monoid monoid
         #tag tag
-        #root {0 #0 value}]))
+        #root {.#Left value}]))
     
     (def: (branch left right)
       (:abstraction
        [#monoid monoid
         #tag (# monoid composite (..tag left) (..tag right))
-        #root {0 #1 [left right]}])))
+        #root {.#Right [left right]}])))
 
   (def: .public (value tree)
     (All (_ @ t v) (-> (Tree @ t v) v))
diff --git a/stdlib/source/library/lux/ffi.jvm.lux b/stdlib/source/library/lux/ffi.jvm.lux
index 59d2b2374..46ffa8021 100644
--- a/stdlib/source/library/lux/ffi.jvm.lux
+++ b/stdlib/source/library/lux/ffi.jvm.lux
@@ -1258,9 +1258,9 @@
 (syntax: .public (??? [expr <code>.any])
   (with_symbols [g!temp]
     (in (list (` (let [(~ g!temp) (~ expr)]
-                   (if ("jvm object null?" (~ g!temp))
-                     {.#None}
-                     {.#Some (~ g!temp)})))))))
+                   (if (not ("jvm object null?" (~ g!temp)))
+                     {.#Some (~ g!temp)}
+                     {.#None})))))))
 
 (syntax: .public (!!! [expr <code>.any])
   (with_symbols [g!value]
diff --git a/stdlib/source/library/lux/math/random.lux b/stdlib/source/library/lux/math/random.lux
index 469a17226..1b3a9426a 100644
--- a/stdlib/source/library/lux/math/random.lux
+++ b/stdlib/source/library/lux/math/random.lux
@@ -352,7 +352,7 @@
   (let [magic 6364136223846793005]
     (function (_ _)
       [(|> seed .nat (n.* magic) ("lux i64 +" increase) [increase] pcg_32)
-       (let [rot (|> seed .i64 (i64.right_shifted 59))]
+       (let [rot (|> seed .nat (i64.right_shifted 59))]
          (|> seed
              (i64.right_shifted 18)
              (i64.xor seed)
diff --git a/stdlib/source/library/lux/target/python.lux b/stdlib/source/library/lux/target/python.lux
index 87864e062..dc1b5e935 100644
--- a/stdlib/source/library/lux/target/python.lux
+++ b/stdlib/source/library/lux/target/python.lux
@@ -450,7 +450,7 @@
 
   (def: .public (comment commentary on)
     (All (_ brand) (-> Text (Code brand) (Code brand)))
-    (:abstraction (format "# "  (..safe commentary) \n+
+    (:abstraction (format "# "  (text.replaced text.\n "\n" commentary) \n+
                           (:representation on))))
   )
 
diff --git a/stdlib/source/library/lux/tool/compiler/default/platform.lux b/stdlib/source/library/lux/tool/compiler/default/platform.lux
index ef79450e9..f13ffecd2 100644
--- a/stdlib/source/library/lux/tool/compiler/default/platform.lux
+++ b/stdlib/source/library/lux/tool/compiler/default/platform.lux
@@ -51,6 +51,7 @@
      [phase
       ["[0]" extension {"+" Extender}]]]]
    [meta
+    [import {"+" Import}]
     [cli {"+" Compilation Library}
      ["[0]" compiler {"+" Compiler}]]
     ["[0]" archive {"+" Output Archive}
@@ -64,7 +65,6 @@
      ["ioW" archive]]]]]
  [program
   [compositor
-   [import {"+" Import}]
    ["[0]" static {"+" Static}]]])
 
 (with_expansions [<type_vars> (as_is anchor expression directive)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux b/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
index 2d231f1cc..65b191979 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/analysis.lux
@@ -159,7 +159,8 @@
 (def: .public (reification analysis)
   (-> Analysis (Reification Analysis))
   (loop [abstraction analysis
-         inputs (list)]
+         inputs (: (List Analysis)
+                   (list))]
     (.case abstraction
       {#Apply input next}
       (again next {.#Item input inputs})
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/inference.lux b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/inference.lux
index 1b693629a..6ca7137d2 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/inference.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/inference.lux
@@ -3,7 +3,7 @@
   [lux "*"
    ["[0]" meta]
    [abstract
-    [monad {"+" do}]]
+    ["[0]" monad {"+" do}]]
    [control
     [pipe {"+" case>}]
     ["[0]" maybe]
@@ -53,25 +53,6 @@
   [invalid_type_application]
   )
 
-(def: prefix
-  (format (%.symbol (symbol ..type)) "#"))
-
-(def: .public (existential? type)
-  (-> Type Bit)
-  (case type
-    {.#Primitive actual {.#End}}
-    (text.starts_with? ..prefix actual)
-
-    _
-    false))
-
-(def: existential
-  (Operation Type)
-  (do phase.monad
-    [module (extension.lifted meta.current_module_name)
-     [id _] (/type.check check.existential)]
-    (in {.#Primitive (format ..prefix module "#" (%.nat id)) (list)})))
-
 (def: .public (quantified @var @parameter :it:)
   (-> check.Var Nat Type Type)
   (case :it:
@@ -111,33 +92,34 @@
 ... tagged variants).
 ... But, so long as the type being used for the inference can be treated
 ... as a function type, this method of inference should work.
-(def: .public (general archive analyse inferT args)
-  (-> Archive Phase Type (List Code) (Operation [Type (List Analysis)]))
+(def: (general' vars archive analyse inferT args)
+  (-> (List check.Var) Archive Phase Type (List Code) (Operation [Type_Context (List check.Var) Type (List Analysis)]))
   (case args
     {.#End}
     (do phase.monad
-      [_ (/type.inference inferT)]
-      (in [inferT (list)]))
+      [just_before (/type.check check.context)
+       _ (/type.inference inferT)]
+      (in [just_before vars inferT (list)]))
     
     {.#Item argC args'}
     (case inferT
       {.#Named name unnamedT}
-      (general archive analyse unnamedT args)
+      (general' vars archive analyse unnamedT args)
 
       {.#UnivQ _}
       (do phase.monad
         [[@var :var:] (/type.check check.var)]
-        (general archive analyse (maybe.trusted (type.applied (list :var:) inferT)) args))
+        (general' (list& @var vars) archive analyse (maybe.trusted (type.applied (list :var:) inferT)) args))
 
       {.#ExQ _}
       (do phase.monad
-        [:ex: ..existential]
-        (general archive analyse (maybe.trusted (type.applied (list :ex:) inferT)) args))
+        [:ex: /type.existential]
+        (general' vars archive analyse (maybe.trusted (type.applied (list :ex:) inferT)) args))
 
       {.#Apply inputT transT}
       (case (type.applied (list inputT) transT)
         {.#Some outputT}
-        (general archive analyse outputT args)
+        (general' vars archive analyse outputT args)
 
         {.#None}
         (/.except ..invalid_type_application [inferT]))
@@ -151,18 +133,18 @@
       ... things together more easily.
       {.#Function inputT outputT}
       (do phase.monad
-        [[outputT' args'A] (general archive analyse outputT args')
+        [[just_before vars outputT' args'A] (general' vars archive analyse outputT args')
          argA (<| (/.with_exception ..cannot_infer_argument [inputT argC])
                   (/type.expecting inputT)
                   (analyse archive argC))]
-        (in [outputT' (list& argA args'A)]))
+        (in [just_before vars outputT' (list& argA args'A)]))
 
       {.#Var infer_id}
       (do phase.monad
         [?inferT' (/type.check (check.peek infer_id))]
         (case ?inferT'
           {.#Some inferT'}
-          (general archive analyse inferT' args)
+          (general' vars archive analyse inferT' args)
 
           _
           (/.except ..cannot_infer [inferT args])))
@@ -171,6 +153,40 @@
       (/.except ..cannot_infer [inferT args]))
     ))
 
+(def: .public (general archive analyse inferT args)
+  (-> Archive Phase Type (List Code) (Operation [Type (List Analysis)]))
+  (do [! phase.monad]
+    [[just_before vars :inference: terms] (general' (list) archive analyse inferT args)]
+    (in [:inference: terms])
+    ... (case vars
+    ...   (^ (list))
+    ...   (in [:inference: terms])
+
+    ...   _
+    ...   (do !
+    ...     [:inference: (/type.check
+    ...                   (do [! check.monad]
+    ...                     [quantifications (monad.mix ! (function (_ @var level)
+    ...                                                     (do !
+    ...                                                       [:var: (check.try (check.identity vars @var))]
+    ...                                                       (case :var:
+    ...                                                         {try.#Success _}
+    ...                                                         (in level)
+
+    ...                                                         {try.#Failure _}
+    ...                                                         (do !
+    ...                                                           [.let [:var: (|> level (n.* 2) ++ {.#Parameter})]
+    ...                                                            _ (check.bind :var: @var)]
+    ...                                                           (in (++ level))))))
+    ...                                                 0
+    ...                                                 vars)
+    ...                      :inference:' (# ! each (type.univ_q quantifications) (check.clean vars :inference:))
+    ...                      _ (check.with just_before)]
+    ...                     (in :inference:')))
+    ...      _ (/type.inference :inference:)]
+    ...     (in [:inference: terms])))
+    ))
+
 (def: (with_recursion @self recursion)
   (-> Nat Type Type Type)
   (function (again it)
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/type.lux b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/type.lux
index c066115ec..bd2c04844 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/analysis/type.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/analysis/type.lux
@@ -3,10 +3,18 @@
   [lux "*"
    ["[0]" meta]
    [abstract
-    [monad {"+" do}]]
+    ["[0]" monad {"+" do}]]
    [control
     ["[0]" function]
     ["[0]" try]]
+   [data
+    ["[0]" text
+     ["%" format {"+" format}]]
+    [collection
+     ["[0]" list]]]
+   [math
+    [number
+     ["n" nat]]]
    [type
     ["[0]" check {"+" Check}]]]]
  ["/" // {"+" Operation}
@@ -16,11 +24,6 @@
    [///
     ["[0]" phase]]]])
 
-(def: .public (expecting expected)
-  (All (_ a) (-> Type (Operation a) (Operation a)))
-  (extension.localized (value@ .#expected) (with@ .#expected)
-                       (function.constant {.#Some expected})))
-
 (def: .public (check action)
   (All (_ a) (-> (Check a) (Operation a)))
   (function (_ (^@ stateE [bundle state]))
@@ -32,6 +35,34 @@
       {try.#Failure error}
       ((/.failure error) stateE))))
 
+(def: prefix
+  (format (%.symbol (symbol ..type)) "#"))
+
+(def: .public (existential? type)
+  (-> Type Bit)
+  (case type
+    {.#Primitive actual {.#End}}
+    (text.starts_with? ..prefix actual)
+
+    _
+    false))
+
+(def: (existential' module id)
+  (-> Text Nat Type)
+  {.#Primitive (format ..prefix module "#" (%.nat id)) (list)})
+
+(def: .public existential
+  (Operation Type)
+  (do phase.monad
+    [module (extension.lifted meta.current_module_name)
+     [id _] (..check check.existential)]
+    (in (..existential' module id))))
+
+(def: .public (expecting expected)
+  (All (_ a) (-> Type (Operation a) (Operation a)))
+  (extension.localized (value@ .#expected) (with@ .#expected)
+                       (function.constant {.#Some expected})))
+
 (def: .public fresh
   (All (_ a) (-> (Operation a) (Operation a)))
   (extension.localized (value@ .#type_context) (with@ .#type_context)
@@ -40,8 +71,44 @@
 (def: .public (inference actualT)
   (-> Type (Operation Any))
   (do phase.monad
-    [expectedT (extension.lifted meta.expected_type)]
-    (..check (check.check expectedT actualT))))
+    [module (extension.lifted meta.current_module_name)
+     expectedT (extension.lifted meta.expected_type)]
+    (..check (check.check expectedT actualT)
+             ... (do [! check.monad]
+             ...   [pre check.context
+             ...    it (check.check expectedT actualT)
+             ...    post check.context
+             ...    .let [pre#var_counter (value@ .#var_counter pre)]]
+             ...   (if (n.< (value@ .#var_counter post)
+             ...            pre#var_counter)
+             ...     (do !
+             ...       [.let [new! (: (-> [Nat (Maybe Type)] (Maybe Nat))
+             ...                      (function (_ [id _])
+             ...                        (if (n.< id pre#var_counter)
+             ...                          {.#Some id}
+             ...                          {.#None})))
+             ...              new_vars (|> post
+             ...                           (value@ .#var_bindings)
+             ...                           (list.all new!))]
+             ...        _ (monad.each ! (function (_ @new)
+             ...                          (do !
+             ...                            [:new: (check.try (check.identity new_vars @new))]
+             ...                            (case :new:
+             ...                              {try.#Success :new:}
+             ...                              (in :new:)
+             
+             ...                              {try.#Failure error}
+             ...                              (do !
+             ...                                [[id _] check.existential
+             ...                                 .let [:new: (..existential' module id)]
+             ...                                 _ (check.bind :new: @new)]
+             ...                                (in :new:)))))
+             ...                      new_vars)
+             ...        expectedT' (check.clean new_vars expectedT)
+             ...        _ (check.with pre)]
+             ...       (check.check expectedT' actualT))
+             ...     (in it)))
+             )))
 
 (def: .public (with_var it)
   (All (_ a) (-> (-> [check.Var Type] (Operation a))
@@ -50,7 +117,8 @@
     [var (..check check.var)
      .let [[@it :it:] var]
      it (it var)
-     _ (..check (check.forget! @it))]
+     ... _ (..check (check.forget! @it))
+     ]
     (in it)))
 
 (def: .public (inferring action)
@@ -58,5 +126,10 @@
   (do phase.monad
     [[@it :it:] (..check check.var)
      it (..expecting :it: action)
-     :it: (..check (check.clean :it:))]
+     :it: (..check (check.clean (list) :it:))
+     ... :it: (..check (do check.monad
+     ...                 [:it: (check.identity (list) @it)
+     ...                  _ (check.forget! @it)]
+     ...                 (in :it:)))
+     ]
     (in [:it: it])))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/complex.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/complex.lux
index 726860314..cce7b1f00 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/complex.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/analysis/complex.lux
@@ -105,7 +105,7 @@
     (function (again valueC)
       (do [! ///.monad]
         [expectedT (///extension.lifted meta.expected_type)
-         expectedT' (/type.check (check.clean expectedT))]
+         expectedT' (/type.check (check.clean (list) expectedT))]
         (/.with_exception ..cannot_analyse_variant [expectedT' lefts right? valueC]
           (case expectedT
             {.#Sum _}
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
index a7d889777..2338824c4 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/analysis/jvm.lux
@@ -461,7 +461,7 @@
          [var_id varT] (typeA.check check.var)
          arrayA (<| (typeA.expecting (.type (array.Array varT)))
                     (analyse archive arrayC))
-         varT (typeA.check (check.clean varT))
+         varT (typeA.check (check.clean (list) varT))
          arrayJT (jvm_array_type (.type (array.Array varT)))]
         (in {/////analysis.#Extension extension_name (list (/////analysis.text (..signature arrayJT))
                                                            arrayA)}))
@@ -667,7 +667,7 @@
          _ (typeA.inference varT)
          arrayA (<| (typeA.expecting (.type (array.Array varT)))
                     (analyse archive arrayC))
-         varT (typeA.check (check.clean varT))
+         varT (typeA.check (check.clean (list) varT))
          arrayJT (jvm_array_type (.type (array.Array varT)))
          idxA (<| (typeA.expecting ..int)
                   (analyse archive idxC))]
@@ -710,7 +710,7 @@
          _ (typeA.inference (.type (array.Array varT)))
          arrayA (<| (typeA.expecting (.type (array.Array varT)))
                     (analyse archive arrayC))
-         varT (typeA.check (check.clean varT))
+         varT (typeA.check (check.clean (list) varT))
          arrayJT (jvm_array_type (.type (array.Array varT)))
          idxA (<| (typeA.expecting ..int)
                   (analyse archive idxC))
diff --git a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/directive/lux.lux b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/directive/lux.lux
index 04006e52f..e159172b2 100644
--- a/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/directive/lux.lux
+++ b/stdlib/source/library/lux/tool/compiler/language/lux/phase/extension/directive/lux.lux
@@ -146,7 +146,7 @@
                                 (do !
                                   [[code//type codeA] (typeA.inferring
                                                        (analyse archive codeC))
-                                   code//type (typeA.check (check.clean code//type))]
+                                   code//type (typeA.check (check.clean (list) code//type))]
                                   (in [code//type codeA]))
 
                                 {.#Some expected}
diff --git a/stdlib/source/library/lux/tool/compiler/meta/archive.lux b/stdlib/source/library/lux/tool/compiler/meta/archive.lux
index d8347d9fd..4ec08ed90 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/archive.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/archive.lux
@@ -108,7 +108,7 @@
         {try.#Success [/#next
                        (|> archive
                            :representation
-                           (revised@ #resolver (dictionary.has module [/#next {.#None}]))
+                           (revised@ #resolver (dictionary.has module [/#next (: (Maybe (Entry Any)) {.#None})]))
                            (revised@ #next ++)
                            :abstraction)]})))
 
@@ -261,7 +261,7 @@
       (in (:abstraction
            [#next next
             #resolver (list#mix (function (_ [module id] archive)
-                                  (dictionary.has module [id {.#None}] archive))
+                                  (dictionary.has module [id (: (Maybe (Entry Any)) {.#None})] archive))
                                 (value@ #resolver (:representation ..empty))
                                 reservations)]))))
   )
diff --git a/stdlib/source/library/lux/tool/compiler/meta/export.lux b/stdlib/source/library/lux/tool/compiler/meta/export.lux
index 79c5a2a44..9b21de75b 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/export.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/export.lux
@@ -30,7 +30,13 @@
 (def: .public file
   "library.tar")
 
-(def: commons
+(def: .public mode
+  ($_ tar.and
+      tar.read_by_owner tar.write_by_owner
+      tar.read_by_group tar.write_by_group
+      tar.read_by_other))
+
+(def: .public ownership
   tar.Ownership
   (let [commons (: tar.Owner
                    [tar.#name tar.anonymous
@@ -51,11 +57,8 @@
                                                                 tar.path)]
                                                       (try#each (|>> [path
                                                                       (instant.of_millis +0)
-                                                                      ($_ tar.and
-                                                                          tar.read_by_owner tar.write_by_owner
-                                                                          tar.read_by_group tar.write_by_group
-                                                                          tar.read_by_other)
-                                                                      ..commons]
+                                                                      ..mode
+                                                                      ..ownership]
                                                                      {tar.#Normal})
                                                                 (tar.content source_code)))))
                                       (try#each sequence.of_list)))
diff --git a/stdlib/source/program/compositor/import.lux b/stdlib/source/library/lux/tool/compiler/meta/import.lux
index 7f21f20ec..d3a356c43 100644
--- a/stdlib/source/program/compositor/import.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/import.lux
@@ -7,13 +7,13 @@
     ["[0]" try {"+" Try}]
     ["[0]" exception {"+" exception:}]
     [concurrency
-     ["[0]" async {"+" Async} ("[1]#[0]" monad)]]
+     ["[0]" async {"+" Async}]]
     ["<>" parser
      ["<[0]>" binary]]]
    [data
     [binary {"+" Binary}]
     ["[0]" text
-     ["%" format {"+" format}]]
+     ["%" format]]
     [collection
      ["[0]" dictionary {"+" Dictionary}]
      ["[0]" sequence]]
diff --git a/stdlib/source/library/lux/tool/compiler/meta/io/archive.lux b/stdlib/source/library/lux/tool/compiler/meta/io/archive.lux
index 63cae0681..b9b99208f 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/io/archive.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/io/archive.lux
@@ -30,11 +30,11 @@
     ["[0]" file]]]]
  [program
   [compositor
-   [import {"+" Import}]
    ["[0]" static {"+" Static}]]]
  ["[0]" // {"+" Context}
   ["[1][0]" context]
   ["/[1]" //
+   [import {"+" Import}]
    ["[0]" archive {"+" Output Archive}
     ["[0]" registry {"+" Registry}]
     ["[0]" unit]
diff --git a/stdlib/source/library/lux/tool/compiler/meta/io/context.lux b/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
index 2f99ddce1..d576571eb 100644
--- a/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
+++ b/stdlib/source/library/lux/tool/compiler/meta/io/context.lux
@@ -22,11 +22,9 @@
      ["[0]" list]]]
    [world
     ["[0]" file]]]]
- [program
-  [compositor
-   [import {"+" Import}]]]
  ["[0]" // {"+" Context Code}
   ["/[1]" // "_"
+   [import {"+" Import}]
    ["/[1]" // {"+" Input}]
    [archive
     [module
diff --git a/stdlib/source/library/lux/type/check.lux b/stdlib/source/library/lux/type/check.lux
index 31ec9da05..984456187 100644
--- a/stdlib/source/library/lux/type/check.lux
+++ b/stdlib/source/library/lux/type/check.lux
@@ -299,10 +299,7 @@
       _
       (except ..invalid_type_application [funcT argT]))))
 
-(type: Ring
-  (Set Var))
-
-(def: (ring' start)
+(def: .public (ring' start)
   (-> Var (Check (List Var)))
   (function (_ context)
     (loop [current start
@@ -326,7 +323,7 @@
 
 ... TODO: Optimize this by not using sets anymore.
 (def: ring
-  (-> Var (Check Ring))
+  (-> Var (Check (Set Var)))
   (|>> ..ring'
        (check#each (set.of_list n.hash))))
 
@@ -336,15 +333,7 @@
                 (set.member? it @1))
               (..ring @0)))
 
-(exception: (invalid_alias [var Var
-                            expected (List Var)
-                            actual (List Var)])
-  (exception.report
-   ["Var" (n#encoded var)]
-   ["Expected" (exception.listing n#encoded expected)]
-   ["Actual" (exception.listing n#encoded actual)]))
-
-(exception: (cannot_identify [var Var])
+(exception: .public (cannot_identify [var Var])
   (exception.report
    ["Var" (n#encoded var)]))
 
@@ -358,18 +347,18 @@
 
       {.#None}
       (do !
-        [existing_aliases (..ring @)
-         _ (if (list.every? (set.member? existing_aliases) aliases)
-             (in [])
-             (..except ..invalid_alias [@ aliases (set.list existing_aliases)]))
-         .let [forbidden_aliases (set.of_list n.hash (list& @ aliases))
-               allowed_aliases (set.difference forbidden_aliases existing_aliases)]]
-        (case (set.list allowed_aliases)
-          {.#Item identity _}
-          (in {.#Var identity})
-          
-          {.#None}
-          (..except ..cannot_identify [@]))))))
+        [existing_aliases (..ring @)]
+        (if (n.< 2 (set.size existing_aliases))
+          (..except ..cannot_identify [@])
+          (do !
+            [.let [forbidden_aliases (set.of_list n.hash (list& @ aliases))
+                   allowed_aliases (set.difference forbidden_aliases existing_aliases)]]
+            (case (set.list allowed_aliases)
+              {.#Item identity _}
+              (in {.#Var identity})
+              
+              {.#None}
+              (..except ..cannot_identify [@]))))))))
 
 (def: (erase! @)
   (-> Var (Check Any))
@@ -639,7 +628,7 @@
       _
       ..silent_failure!)))
 
-(def: (with exception parameter check)
+(def: (with_exception exception parameter check)
   (All (_ e a) (-> (Exception e) e (Check a) (Check a)))
   (|>> check
        (exception.with exception parameter)))
@@ -652,7 +641,7 @@
             @.php false]
            (same? expected actual))
     (check#in assumptions)
-    (with ..type_check_failed [expected actual]
+    (with_exception ..type_check_failed [expected actual]
       (case [expected actual]
         [{.#Var idE} {.#Var idA}]
         (check_vars check' assumptions idE idA)
@@ -774,12 +763,17 @@
   (function (_ context)
     {try.#Success [context context]}))
 
-(def: .public (clean inputT)
-  (-> Type (Check Type))
+(def: .public (with context)
+  (-> Type_Context (Check Any))
+  (function (_ _)
+    {try.#Success [context []]}))
+
+(def: .public (clean aliases inputT)
+  (-> (List Var) Type (Check Type))
   (case inputT
     {.#Primitive name paramsT+}
     (|> paramsT+
-        (monad.each ..monad clean)
+        (monad.each ..monad (clean aliases))
         (check#each (|>> {.#Primitive name})))
 
     (^or {.#Parameter _} {.#Ex _} {.#Named _})
@@ -788,26 +782,43 @@
     (^template [<tag>]
       [{<tag> leftT rightT}
        (do ..monad
-         [leftT' (clean leftT)]
-         (|> (clean rightT)
+         [leftT' (clean aliases leftT)]
+         (|> (clean aliases rightT)
              (check#each (|>> {<tag> leftT'}))))])
     ([.#Sum] [.#Product] [.#Function] [.#Apply])
 
     {.#Var @}
-    (do ..monad
-      [?actualT (peek @)]
-      (case ?actualT
-        {.#Some actualT}
-        (clean actualT)
+    (case aliases
+      (^ (list))
+      (do ..monad
+        [?actualT (peek @)]
+        (case ?actualT
+          {.#Some actualT}
+          (clean aliases actualT)
 
-        _
-        (in inputT)))
+          _
+          (in inputT)))
+
+      _
+      (do ..monad
+        [:it: (..try (..identity aliases @))]
+        (case :it:
+          {try.#Success :it:}
+          (case :it:
+            {.#Var _}
+            (in inputT)
+
+            _
+            (clean aliases :it:))
+
+          failure
+          (in inputT))))
 
     (^template [<tag>]
       [{<tag> envT+ unquantifiedT}
        (do [! ..monad]
-         [envT+' (monad.each ! clean envT+)
-          unquantifiedT' (clean unquantifiedT)]
+         [envT+' (monad.each ! (clean aliases) envT+)
+          unquantifiedT' (clean aliases unquantifiedT)]
          (in {<tag> envT+' unquantifiedT'}))])
     ([.#UnivQ] [.#ExQ])
     ))
diff --git a/stdlib/source/library/lux/world/program.lux b/stdlib/source/library/lux/world/program.lux
index 950f19206..5fdc9cc21 100644
--- a/stdlib/source/library/lux/world/program.lux
+++ b/stdlib/source/library/lux/world/program.lux
@@ -306,10 +306,11 @@
   (Program IO)
 
   (def: (available_variables _)
-    (with_expansions [<jvm> (io.io (|> (java/lang/System::getenv)
-                                       java/util/Map::keySet
-                                       java/util/Set::iterator
-                                       ..jvm##consume))]
+    (with_expansions [<jvm> (|> (java/lang/System::getenv)
+                                java/util/Map::keySet
+                                java/util/Set::iterator
+                                ..jvm##consume
+                                io.io)]
       (for [@.old <jvm>
             @.jvm <jvm>
             @.js (io.io (if ffi.on_node_js?
@@ -325,9 +326,7 @@
             @.python (# io.monad each (array.list {.#None}) (os/environ::keys []))
             ... Lua offers no way to get all the environment variables available.
             @.lua (io.io (list))
-            @.ruby (|> (RubyEnv::keys [])
-                       (array.list {.#None})
-                       io.io)
+            @.ruby (io.io (array.list {.#None} (RubyEnv::keys [])))
             ... @.php (do io.monad
             ...         [environment (..getenv/0 [])]
             ...         (in (|> environment
diff --git a/stdlib/source/program/compositor.lux b/stdlib/source/program/compositor.lux
index 55da4161b..4e0599859 100644
--- a/stdlib/source/program/compositor.lux
+++ b/stdlib/source/program/compositor.lux
@@ -42,6 +42,7 @@
      [meta
       [packager {"+" Packager}]
       ["[0]" cli {"+" Service}]
+      ["[0]" import]
       ["[0]" export]
       [archive {"+" Archive}
        ["[0]" unit]
@@ -52,8 +53,7 @@
     ... ["[0]" interpreter]
     ]]]
  ["[0]" / "_"
-  ["[1][0]" static {"+" Static}]
-  ["[1][0]" import]])
+  ["[1][0]" static {"+" Static}]])
 
 (def: (or_crash! failure_description action)
   (All (_ a)
@@ -153,7 +153,7 @@
             ..timed
             (do (try.with async.monad)
               [.let [[compilation_host_dependencies compilation_libraries compilation_compilers compilation_sources compilation_target compilation_module] compilation]
-               import (/import.import (value@ platform.#&file_system platform) compilation_libraries)
+               import (import.import (value@ platform.#&file_system platform) compilation_libraries)
                [state archive phase_wrapper] (:sharing [<parameters>]
                                                        (Platform <parameters>)
                                                        platform
diff --git a/stdlib/source/specification/lux/abstract/apply.lux b/stdlib/source/specification/lux/abstract/apply.lux
index 867a7b76f..3d01a1217 100644
--- a/stdlib/source/specification/lux/abstract/apply.lux
+++ b/stdlib/source/specification/lux/abstract/apply.lux
@@ -1,65 +1,69 @@
 (.using
-  [library
-   [lux "*"
-    ["_" test {"+" Test}]
-    [abstract
-     [monad {"+" do}]]
-    [control
-     ["[0]" function]]
-    [math
-     ["[0]" random]
-     [number
-      ["n" nat]]]]]
-  [\\library
-   ["[0]" / {"+" Apply}]]
-  [//
-   [functor {"+" Injection Comparison}]])
+ [library
+  [lux "*"
+   ["_" test {"+" Test}]
+   [abstract
+    [monad {"+" do}]]
+   [control
+    ["[0]" function]]
+   [math
+    ["[0]" random {"+" Random}]
+    [number
+     ["n" nat]]]]]
+ [\\library
+  ["[0]" / {"+" Apply}]]
+ [//
+  [functor {"+" Injection Comparison}]])
 
-(def: (identity injection comparison (^open "#[0]"))
+(def: (identity injection comparison (^open "/#[0]"))
   (All (_ f) (-> (Injection f) (Comparison f) (Apply f) Test))
   (do [! random.monad]
     [sample (# ! each injection random.nat)]
     (_.test "Identity."
             ((comparison n.=)
-             (#on sample (injection function.identity))
+             (/#on sample (injection function.identity))
              sample))))
 
-(def: (homomorphism injection comparison (^open "#[0]"))
+(def: (homomorphism injection comparison (^open "/#[0]"))
   (All (_ f) (-> (Injection f) (Comparison f) (Apply f) Test))
   (do [! random.monad]
     [sample random.nat
      increase (# ! each n.+ random.nat)]
     (_.test "Homomorphism."
             ((comparison n.=)
-             (#on (injection sample) (injection increase))
+             (/#on (injection sample) (injection increase))
              (injection (increase sample))))))
 
-(def: (interchange injection comparison (^open "#[0]"))
+(def: (interchange injection comparison (^open "/#[0]"))
   (All (_ f) (-> (Injection f) (Comparison f) (Apply f) Test))
   (do [! random.monad]
     [sample random.nat
      increase (# ! each n.+ random.nat)]
     (_.test "Interchange."
             ((comparison n.=)
-             (#on (injection sample) (injection increase))
-             (#on (injection increase) (injection (: (-> (-> Nat Nat) Nat)
-                                                     (function (_ f) (f sample)))))))))
+             (/#on (injection sample) (injection increase))
+             (/#on (injection increase) (injection (: (-> (-> Nat Nat) Nat)
+                                                      (function (_ f) (f sample)))))))))
 
-(def: (composition injection comparison (^open "#[0]"))
+(def: (composition injection comparison (^open "/#[0]"))
   (All (_ f) (-> (Injection f) (Comparison f) (Apply f) Test))
-  (do [! random.monad]
-    [sample random.nat
-     increase (# ! each n.+ random.nat)
-     decrease (# ! each n.- random.nat)]
-    (_.test "Composition."
-            ((comparison n.=)
-             (|> (injection function.composite)
-                 (#on (injection increase))
-                 (#on (injection decrease))
-                 (#on (injection sample)))
-             (#on (#on (injection sample)
-                       (injection increase))
-                  (injection decrease))))))
+  (:let [:$/1: (-> Nat Nat)]
+    (do [! random.monad]
+      [sample random.nat
+       increase (: (Random :$/1:)
+                   (# ! each n.+ random.nat))
+       decrease (: (Random :$/1:)
+                   (# ! each n.- random.nat))]
+      (_.test "Composition."
+              ((comparison n.=)
+               (|> (injection (: (-> :$/1: :$/1: :$/1:)
+                                 function.composite))
+                   (/#on (injection increase))
+                   (/#on (injection decrease))
+                   (/#on (injection sample)))
+               (/#on (/#on (injection sample)
+                           (injection increase))
+                     (injection decrease)))))))
 
 (def: .public (spec injection comparison apply)
   (All (_ f) (-> (Injection f) (Comparison f) (Apply f) Test))
diff --git a/stdlib/source/test/lux/control/concatenative.lux b/stdlib/source/test/lux/control/concatenative.lux
index 00b421f97..85a1f4ac8 100644
--- a/stdlib/source/test/lux/control/concatenative.lux
+++ b/stdlib/source/test/lux/control/concatenative.lux
@@ -141,8 +141,10 @@
      sample random.nat
      start random.nat
      .let [distance 10
-           |++| (/.apply/1 ++)
-           |test| (/.apply/1 (|>> (n.- start) (n.< distance)))]]
+           |++| (: (/.=> [Nat] [Nat])
+                   (/.apply/1 ++))
+           |test| (: (/.=> [Nat] [Bit])
+                     (/.apply/1 (|>> (n.- start) (n.< distance))))]]
     ($_ _.and
         (_.cover [/.call /.apply/1]
                  (n.= (++ sample)
@@ -244,18 +246,21 @@
         (_.cover [/.loop]
                  (n.= (n.+ distance start)
                       (||> (/.push start)
-                           (/.push (|>> |++| /.dup |test|))
+                           (/.push (: (/.=> [Nat] [Nat Bit])
+                                      (|>> |++| /.dup |test|)))
                            /.loop)))
         (_.cover [/.while]
                  (n.= (n.+ distance start)
                       (||> (/.push start)
-                           (/.push (|>> /.dup |test|))
+                           (/.push (: (/.=> [Nat] [Nat Bit])
+                                      (|>> /.dup |test|)))
                            (/.push |++|)
                            /.while)))
         (_.cover [/.do]
                  (n.= (++ sample)
                       (||> (/.push sample)
-                           (/.push (|>> (/.push false)))
+                           (/.push (: (/.=> [] [Bit])
+                                      (|>> (/.push false))))
                            (/.push |++|)
                            /.do /.while)))
         (_.cover [/.compose]
diff --git a/stdlib/source/test/lux/control/concurrency/frp.lux b/stdlib/source/test/lux/control/concurrency/frp.lux
index 466f1c61f..7b564d904 100644
--- a/stdlib/source/test/lux/control/concurrency/frp.lux
+++ b/stdlib/source/test/lux/control/concurrency/frp.lux
@@ -1,30 +1,30 @@
 (.using
-  [library
-   [lux "*"
-    ["_" test {"+" Test}]
-    [abstract
-     [monad {"+" do}]
-     [\\specification
-      ["$[0]" functor {"+" Injection Comparison}]
-      ["$[0]" apply]
-      ["$[0]" monad]]]
-    [control
-     ["[0]" try]
-     ["[0]" exception]
-     ["[0]" io {"+" IO io}]]
-    [data
-     [collection
-      ["[0]" list ("[1]#[0]" mix monoid)]
-      ["[0]" sequence {"+" Sequence}]]]
-    [math
-     ["[0]" random]
-     [number
-      ["n" nat]]]]]
-  [\\library
-   ["[0]" /
-    [//
-     ["[0]" async {"+" Async} ("[1]#[0]" monad)]
-     ["[0]" atom {"+" Atom atom}]]]])
+ [library
+  [lux "*"
+   ["_" test {"+" Test}]
+   [abstract
+    [monad {"+" do}]
+    [\\specification
+     ["$[0]" functor {"+" Injection Comparison}]
+     ["$[0]" apply]
+     ["$[0]" monad]]]
+   [control
+    ["[0]" try]
+    ["[0]" exception]
+    ["[0]" io {"+" IO io}]]
+   [data
+    [collection
+     ["[0]" list ("[1]#[0]" mix monoid)]
+     ["[0]" sequence {"+" Sequence}]]]
+   [math
+    ["[0]" random]
+    [number
+     ["n" nat]]]]]
+ [\\library
+  ["[0]" /
+   [//
+    ["[0]" async {"+" Async} ("[1]#[0]" monad)]
+    ["[0]" atom {"+" Atom atom}]]]])
 
 (def: injection
   (Injection /.Channel)
@@ -86,7 +86,8 @@
               (_.cover [/.Channel /.Sink /.channel]
                        (case (io.run!
                               (do (try.with io.monad)
-                                [.let [[channel sink] (/.channel [])]
+                                [.let [[channel sink] (: [(/.Channel Nat) (/.Sink Nat)]
+                                                         (/.channel []))]
                                  _ (# sink feed sample)
                                  _ (# sink close)]
                                 (in channel)))
@@ -106,7 +107,8 @@
               (_.cover [/.channel_is_already_closed]
                        (case (io.run!
                               (do (try.with io.monad)
-                                [.let [[channel sink] (/.channel [])]
+                                [.let [[channel sink] (: [(/.Channel Nat) (/.Sink Nat)]
+                                                         (/.channel []))]
                                  _ (# sink close)]
                                 (# sink feed sample)))
                          {try.#Success _}
diff --git a/stdlib/source/test/lux/control/maybe.lux b/stdlib/source/test/lux/control/maybe.lux
index a798c19aa..fe8528548 100644
--- a/stdlib/source/test/lux/control/maybe.lux
+++ b/stdlib/source/test/lux/control/maybe.lux
@@ -65,7 +65,8 @@
              value random.nat]
             (_.cover [/.else]
                      (and (same? default (/.else default
-                                                 {.#None}))
+                                                 (: (Maybe Nat)
+                                                    {.#None})))
 
                           (same? value (/.else default
                                                {.#Some value})))))
diff --git a/stdlib/source/test/lux/extension.lux b/stdlib/source/test/lux/extension.lux
index 4c923924b..85b98df02 100644
--- a/stdlib/source/test/lux/extension.lux
+++ b/stdlib/source/test/lux/extension.lux
@@ -185,9 +185,7 @@
           (in directive.no_requirements)))
 
       (for [... TODO: No longer skip testing Lua after Rembulan isn't being used anymore.
-            @.lua (as_is)
-            ... TODO: No longer skip testing Python.
-            @.python (as_is)]
+            @.lua (as_is)]
            (`` ((~~ (static ..directive)) (n.* 2 3))))
       ))
 
diff --git a/stdlib/source/test/lux/tool.lux b/stdlib/source/test/lux/tool.lux
index c9a5cfb7c..8c154b3a0 100644
--- a/stdlib/source/test/lux/tool.lux
+++ b/stdlib/source/test/lux/tool.lux
@@ -24,7 +24,8 @@
    ["[1][0]" meta "_"
     ["[1]/[0]" archive]
     ["[1]/[0]" cli]
-    ["[1]/[0]" export]]
+    ["[1]/[0]" export]
+    ["[1]/[0]" import]]
    ]])
 
 (def: .public test
@@ -38,6 +39,7 @@
       /meta/archive.test
       /meta/cli.test
       /meta/export.test
+      /meta/import.test
       /phase/extension.test
       /phase/analysis/simple.test
       /phase/analysis/complex.test
diff --git a/stdlib/source/test/lux/tool/compiler/language/lux/analysis/inference.lux b/stdlib/source/test/lux/tool/compiler/language/lux/analysis/inference.lux
index 97bdb7a54..3eec3a5b4 100644
--- a/stdlib/source/test/lux/tool/compiler/language/lux/analysis/inference.lux
+++ b/stdlib/source/test/lux/tool/compiler/language/lux/analysis/inference.lux
@@ -108,6 +108,8 @@
         (_.cover [/.general]
                  (and (|> (/.general archive.empty ..analysis expected (list))
                           (//type.expecting expected)
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
                           (/phase.result state)
                           (try#each (|>> product.left (type#= expected)))
                           (try.else false))
@@ -115,6 +117,8 @@
                                      (type.function (list.repeated arity .Nat) expected)
                                      (list#each code.nat nats))
                           (//type.expecting expected)
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
                           (/phase.result state)
                           (try#each (function (_ [actual analysis/*])
                                       (and (type#= expected actual)
@@ -126,6 +130,8 @@
                                      (type (-> type/0 expected))
                                      (list term/0))
                           (//type.expecting expected)
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
                           (/phase.result state)
                           (try#each (|>> product.left (type#= expected)))
                           (try.else false))
@@ -133,6 +139,8 @@
                                      (type {.#Named name (-> type/0 expected)})
                                      (list term/0))
                           (//type.expecting expected)
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
                           (/phase.result state)
                           (try#each (|>> product.left (type#= expected)))
                           (try.else false))
@@ -140,7 +148,9 @@
                                      (type (All (_ a) (-> a a)))
                                      (list term/0))
                           (//type.expecting type/0)
-                          (/phase#each (|>> product.left check.clean //type.check))
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
+                          (/phase#each (|>> product.left (check.clean (list)) //type.check))
                           /phase#conjoint
                           (/phase.result state)
                           (try#each (type#= type/0))
@@ -149,6 +159,8 @@
                                      (type ((All (_ a) (-> a a)) type/0))
                                      (list term/0))
                           (//type.expecting type/0)
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
                           (/phase.result state)
                           (try#each (|>> product.left (type#= type/0)))
                           (try.else false))
@@ -157,11 +169,23 @@
                              _ (//type.check (check.check varT (type (-> type/0 expected))))]
                             (/.general archive.empty ..analysis varT (list term/0)))
                           (//type.expecting expected)
-                          (/phase#each (|>> product.left check.clean //type.check))
+                          (//module.with 0 (product.left name))
+                          (/phase#each product.right)
+                          (/phase#each (|>> product.left (check.clean (list)) //type.check))
                           /phase#conjoint
                           (/phase.result state)
                           (try#each (type#= expected))
                           (try.else false))
+                      (|> (/.general archive.empty ..analysis
+                                     (type (Ex (_ a) (-> a a)))
+                                     (list (` ("lux io error" ""))))
+                          //type.inferring
+                          (//module.with 0 (product.left name))
+                          (/phase#each (|>> product.right product.left (check.clean (list)) //type.check))
+                          /phase#conjoint
+                          (/phase.result state)
+                          (try#each //type.existential?)
+                          (try.else false))
                       ))
         (_.cover [/.cannot_infer]
                  (and (|> (/.general archive.empty ..analysis expected (list term/0))
@@ -179,19 +203,9 @@
                                 (type (-> expected expected))
                                 (list term/0))
                      (//type.expecting expected)
-                     (/phase.result state)
-                     (..fails? /.cannot_infer_argument)))
-        (_.cover [/.existential?]
-                 (|> (/.general archive.empty ..analysis
-                                (type (Ex (_ a) (-> a a)))
-                                (list (` ("lux io error" ""))))
-                     //type.inferring
                      (//module.with 0 (product.left name))
-                     (/phase#each (|>> product.right product.left check.clean //type.check))
-                     /phase#conjoint
                      (/phase.result state)
-                     (try#each /.existential?)
-                     (try.else false)))
+                     (..fails? /.cannot_infer_argument)))
         )))
 
 (def: test|variant
diff --git a/stdlib/source/test/lux/tool/compiler/language/lux/analysis/type.lux b/stdlib/source/test/lux/tool/compiler/language/lux/analysis/type.lux
index 2e63f1bc8..867ef7e5a 100644
--- a/stdlib/source/test/lux/tool/compiler/language/lux/analysis/type.lux
+++ b/stdlib/source/test/lux/tool/compiler/language/lux/analysis/type.lux
@@ -16,11 +16,12 @@
  [\\library
   ["[0]" /
    ["/[1]" //
+    ["[2][0]" module]
     [//
      [phase
       ["[2][0]" extension]]
      [///
-      ["[2][0]" phase]]]]]])
+      ["[2][0]" phase ("[1]#[0]" functor)]]]]]])
 
 (def: .public random_state
   (Random Lux)
@@ -44,27 +45,36 @@
                       /extension.#state lux]]
          expected ..primitive
          dummy (random.only (|>> (type#= expected) not)
-                            ..primitive)]
+                            ..primitive)
+         module (random.ascii/lower 1)]
         ($_ _.and
             (_.cover [/.expecting /.inference]
                      (and (|> (/.inference expected)
                               (/.expecting expected)
+                              (/module.with 0 module)
+                              (/phase#each product.right)
                               (/phase.result state)
                               (case> {try.#Success _} true
                                      {try.#Failure _} false))
                           (|> (/.inference dummy)
                               (/.expecting expected)
+                              (/module.with 0 module)
+                              (/phase#each product.right)
                               (/phase.result state)
                               (case> {try.#Success _} false
                                      {try.#Failure _} true))
                           (|> (/.inference expected)
                               (/.expecting dummy)
+                              (/module.with 0 module)
+                              (/phase#each product.right)
                               (/phase.result state)
                               (case> {try.#Success _} false
                                      {try.#Failure _} true))))
             (_.cover [/.inferring]
                      (|> (/.inference expected)
                          /.inferring
+                         (/module.with 0 module)
+                         (/phase#each product.right)
                          (/phase.result state)
                          (try#each (|>> product.left (type#= expected)))
                          (try.else false)))
@@ -75,9 +85,19 @@
                                            (in type)))]
                            (|> (/.inference exT)
                                (/.expecting exT)))
+                         (/module.with 0 module)
+                         (/phase#each product.right)
                          (/phase.result state)
                          (case> {try.#Success _} true
                                 {try.#Failure _} false)))
+            (_.cover [/.existential /.existential?]
+                     (|> (do /phase.monad
+                           [:it: /.existential]
+                           (in (/.existential? :it:)))
+                         (/module.with 0 module)
+                         (/phase#each product.right)
+                         (/phase.result state)
+                         (try.else false)))
             (_.cover [/.fresh]
                      (and (|> (do /phase.monad
                                 [varT (/.check (do check.monad
@@ -85,6 +105,8 @@
                                                  (in type)))]
                                 (|> (/.inference expected)
                                     (/.expecting varT)))
+                              (/module.with 0 module)
+                              (/phase#each product.right)
                               (/phase.result state)
                               (case> {try.#Success _} true
                                      {try.#Failure _} false))
@@ -95,6 +117,8 @@
                                 (|> (/.inference expected)
                                     (/.expecting varT)
                                     /.fresh))
+                              (/module.with 0 module)
+                              (/phase#each product.right)
                               (/phase.result state)
                               (case> {try.#Success _} false
                                      {try.#Failure _} true))))
diff --git a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/function.lux b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/function.lux
index 50fbc1c50..b5f2e4fc4 100644
--- a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/function.lux
+++ b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/function.lux
@@ -195,59 +195,66 @@
                      (exception.otherwise (text.contains? (value@ exception.#label /.cannot_analyse)))))
         )))
 
+(def: test|apply
+  Test
+  (do [! random.monad]
+    [lux $//type.random_state
+     .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
+                  //extension.#state lux]]
+     [input/0 term/0] $//inference.simple_parameter
+     [input/1 term/1] (random.only (|>> product.left (same? input/0) not)
+                                   $//inference.simple_parameter)
+     output/0 ($type.random 0)
+     module/0 (random.ascii/lower 1)]
+    ($_ _.and
+        (_.cover [/.apply]
+                 (let [reification? (: (-> Type (List Code) Type Bit)
+                                       (function (_ :abstraction: terms :expected:)
+                                         (|> (do //phase.monad
+                                               [[:actual: analysis] (|> (/.apply ..analysis terms
+                                                                                 :abstraction:
+                                                                                 (//analysis.unit)
+                                                                                 archive.empty
+                                                                                 (' []))
+                                                                        //type.inferring)]
+                                               (in (and (check.subsumes? :expected: :actual:)
+                                                        (case analysis
+                                                          {//analysis.#Apply _}
+                                                          true
+
+                                                          _
+                                                          false))))
+                                             (//module.with 0 module/0)
+                                             (//phase#each product.right)
+                                             (//phase.result state)
+                                             (try.else false))))]
+                   (and (reification? (-> input/0 input/1 output/0) (list term/0 term/1) output/0)
+                        (reification? (-> input/0 input/1 output/0) (list term/0) (-> input/1 output/0))
+                        (reification? (All (_ a) (-> a a)) (list term/0) input/0)
+                        (reification? (All (_ a) (-> a a a)) (list term/0) (-> input/0 input/0))
+                        (reification? (All (_ a) (-> input/0 a)) (list term/0) .Nothing)
+                        (reification? (All (_ a b) (-> a b a)) (list term/0) (All (_ b) (-> b input/0)))
+                        (reification? (Ex (_ a) (-> a input/0)) (list (` ("lux io error" ""))) input/0)
+                        (reification? (Ex (_ a) (-> input/0 a)) (list term/0) .Any))))
+        (_.cover [/.cannot_apply]
+                 (|> (do //phase.monad
+                       [_ (|> (/.apply ..analysis (list term/1 term/0)
+                                       (-> input/0 input/1 output/0)
+                                       (//analysis.unit)
+                                       archive.empty
+                                       (' []))
+                              (//type.expecting output/0))]
+                       (in false))
+                     (//module.with 0 module/0)
+                     (//phase#each product.right)
+                     (//phase.result state)
+                     (exception.otherwise (text.contains? (value@ exception.#label /.cannot_apply)))))
+        )))
+
 (def: .public test
   Test
   (<| (_.covering /._)
-      (do [! random.monad]
-        [lux $//type.random_state
-         .let [state [//extension.#bundle (//extension/analysis.bundle ..eval)
-                      //extension.#state lux]]
-         [input/0 term/0] $//inference.simple_parameter
-         [input/1 term/1] $//inference.simple_parameter
-         output/0 ($type.random 0)
-         module/0 (random.ascii/lower 1)]
-        ($_ _.and
-            ..test|function
-            (_.cover [/.apply]
-                     (let [reification? (: (-> Type (List Code) Type Bit)
-                                           (function (_ :abstraction: terms :expected:)
-                                             (|> (do //phase.monad
-                                                   [[:actual: analysis] (|> (/.apply ..analysis terms
-                                                                                     :abstraction:
-                                                                                     (//analysis.unit)
-                                                                                     archive.empty
-                                                                                     (' []))
-                                                                            //type.inferring)]
-                                                   (in (and (check.subsumes? :expected: :actual:)
-                                                            (case analysis
-                                                              {//analysis.#Apply _}
-                                                              true
-
-                                                              _
-                                                              false))))
-                                                 (//module.with 0 module/0)
-                                                 (//phase#each product.right)
-                                                 (//phase.result state)
-                                                 (try.else false))))]
-                       (and (reification? (-> input/0 input/1 output/0) (list term/0 term/1) output/0)
-                            (reification? (-> input/0 input/1 output/0) (list term/0) (-> input/1 output/0))
-                            (reification? (All (_ a) (-> a a)) (list term/0) input/0)
-                            (reification? (All (_ a) (-> a a a)) (list term/0) (-> input/0 input/0))
-                            (reification? (All (_ a) (-> input/0 a)) (list term/0) .Nothing)
-                            (reification? (All (_ a b) (-> a b a)) (list term/0) (All (_ b) (-> b input/0)))
-                            (reification? (Ex (_ a) (-> a input/0)) (list (` ("lux io error" ""))) input/0)
-                            (reification? (Ex (_ a) (-> input/0 a)) (list term/0) .Any))))
-            (_.cover [/.cannot_apply]
-                     (|> (do //phase.monad
-                           [_ (|> (/.apply ..analysis (list term/1 term/0)
-                                           (-> input/0 input/1 output/0)
-                                           (//analysis.unit)
-                                           archive.empty
-                                           (' []))
-                                  (//type.expecting output/0))]
-                           (in false))
-                         (//module.with 0 module/0)
-                         (//phase#each product.right)
-                         (//phase.result state)
-                         (exception.otherwise (text.contains? (value@ exception.#label /.cannot_apply)))))
-            ))))
+      ($_ _.and
+          ..test|function
+          ..test|apply
+          )))
diff --git a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/reference.lux b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/reference.lux
index c16cbf491..af84eb488 100644
--- a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/reference.lux
+++ b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/reference.lux
@@ -49,6 +49,8 @@
                                (//scope.with_local [expected_name expected_type])
                                //type.inferring
                                //scope.with
+                               (//module.with 0 expected_module)
+                               (//phase#each product.right)
                                (//phase.result state)
                                (try#each (|>> product.right
                                               (case> (^ [actual_type (//analysis.local 0)])
@@ -64,6 +66,8 @@
                                //scope.with
                                (//scope.with_local [expected_name expected_type])
                                //scope.with
+                               (//module.with 0 expected_module)
+                               (//phase#each product.right)
                                (//phase.result state)
                                (try#each (|>> product.right
                                               product.right
diff --git a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/simple.lux b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/simple.lux
index a93b4c3e1..45c22f1ec 100644
--- a/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/simple.lux
+++ b/stdlib/source/test/lux/tool/compiler/language/lux/phase/analysis/simple.lux
@@ -8,6 +8,8 @@
    [control
     [pipe {"+" case>}]
     ["[0]" try]]
+   [data
+    ["[0]" product]]
    [math
     ["[0]" random]]]]
  [\\library
@@ -16,14 +18,17 @@
     ["[1][0]" extension]
     [//
      ["[1][0]" analysis {"+" Analysis Operation}
-      ["[2][0]" type]]
+      ["[2][0]" type]
+      ["[2][0]" module]]
      [///
-      ["[1][0]" phase]]]]]])
+      ["[1][0]" phase ("[1]#[0]" functor)]]]]]])
 
-(def: (analysis state type it ?)
-  (-> Lux Type (Operation Analysis) (-> Analysis Bit) Bit)
+(def: (analysis state module type it ?)
+  (-> Lux Text Type (Operation Analysis) (-> Analysis Bit) Bit)
   (and (|> it
            (/type.expecting type)
+           (/module.with 0 module)
+           (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
            (case> (^ {try.#Success analysis})
@@ -33,6 +38,8 @@
                   false))
        (|> it
            (/type.expecting .Nothing)
+           (/module.with 0 module)
+           (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
            (case> (^ {try.#Failure error})
@@ -42,6 +49,8 @@
                   false))
        (|> it
            /type.inferring
+           (/module.with 0 module)
+           (/phase#each product.right)
            (/phase.result [/extension.#bundle /extension.empty
                            /extension.#state state])
            (case> (^ {try.#Success [inferred analysis]})
@@ -64,17 +73,18 @@
   (<| (_.covering /._)
       (do [! random.monad]
         [version random.nat
-         host (random.ascii/lower 5)
+         host (random.ascii/lower 1)
+         module (random.ascii/lower 2)
          .let [state (/analysis.state (/analysis.info version host))]]
         (`` ($_ _.and
                 (_.cover [/.unit]
-                         (..analysis state .Any /.unit
+                         (..analysis state module .Any /.unit
                                      (|>> (case> (^ (/analysis.unit)) true _ false))))
                 (~~ (template [<analysis> <type> <random> <tag>]
                       [(do !
                          [sample <random>]
                          (_.cover [<analysis>]
-                                  (..analysis state <type> (<analysis> sample)
+                                  (..analysis state module <type> (<analysis> sample)
                                               ((..analysis? <type> <tag>) sample))))]
 
                       [/.bit .Bit random.bit /analysis.bit]
diff --git a/stdlib/source/test/lux/tool/compiler/meta/export.lux b/stdlib/source/test/lux/tool/compiler/meta/export.lux
index 11a6ea9ce..2864dabfd 100644
--- a/stdlib/source/test/lux/tool/compiler/meta/export.lux
+++ b/stdlib/source/test/lux/tool/compiler/meta/export.lux
@@ -75,15 +75,19 @@
                          export_tar (# ! in (<binary>.result tar.parser export_tar))]
                         (in [library_tar export_tar]))]
                   ($_ _.and'
-                      (_.cover' [/.library]
+                      (_.cover' [/.library /.mode /.ownership]
                                 (|> it
                                     (try#each (|>> product.left
                                                    sequence.list
-                                                   (case> (^ (list {tar.#Normal [actual_path/0 _ _ _ actual_content/0]}
-                                                                   {tar.#Normal [actual_path/1 _ _ _ actual_content/1]}))
+                                                   (case> (^ (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 [<test> (and (and (text#= file/0' (tar.from_path actual_path/0))
+                                                                                             (same? /.mode mode/0)
+                                                                                             (same? /.ownership ownership/0)
                                                                                              (binary#= content/0 (tar.data actual_content/0)))
                                                                                         (and (text#= file/1' (tar.from_path actual_path/1))
+                                                                                             (same? /.mode mode/1)
+                                                                                             (same? /.ownership ownership/1)
                                                                                              (binary#= content/1 (tar.data actual_content/1))))]
                                                             (or <test>
                                                                 (let [[[actual_path/0 actual_content/0] [actual_path/1 actual_content/1]]
diff --git a/stdlib/source/test/lux/tool/compiler/meta/import.lux b/stdlib/source/test/lux/tool/compiler/meta/import.lux
new file mode 100644
index 000000000..7a24f9a82
--- /dev/null
+++ b/stdlib/source/test/lux/tool/compiler/meta/import.lux
@@ -0,0 +1,158 @@
+(.using
+ [library
+  [lux "*"
+   ["_" test {"+" Test}]
+   [abstract
+    [monad {"+" do}]]
+   [control
+    [pipe {"+" case>}]
+    ["[0]" maybe ("[1]#[0]" functor)]
+    ["[0]" try ("[1]#[0]" functor)]
+    ["[0]" exception]
+    [concurrency
+     ["[0]" async]]
+    [parser
+     ["<[0]>" binary]]]
+   [data
+    ["[0]" product]
+    ["[0]" binary {"+" Binary} ("[1]#[0]" equivalence)]
+    ["[0]" bit ("[1]#[0]" equivalence)]
+    ["[0]" format "_"
+     ["[0]" tar {"+" Tar}]
+     ["[1]" binary]]
+    ["[0]" text ("[1]#[0]" equivalence)
+     ["%" format {"+" format}]
+     [encoding
+      ["[0]" utf8]]]
+    [collection
+     ["[0]" sequence]
+     ["[0]" dictionary]]]
+   [math
+    ["[0]" random {"+" Random}]
+    [number
+     ["n" nat]]]
+   [world
+    ["[0]" file]]]]
+ [\\library
+  ["[0]" /
+   [//
+    ["[0]" export]
+    ["[0]" io "_"
+     ["[1]" context]]]]])
+
+(def: .public test
+  Test
+  (<| (_.covering /._)
+      (_.for [/.Import])
+      (do [! random.monad]
+        [library/0 (random.ascii/lower 1)
+         library/1 (random.ascii/lower 2)
+         
+         .let [/ .module_separator
+               random_file (: (Random file.Path)
+                              (# ! each (text.suffix io.lux_extension) (random.ascii/lower 3)))]
+         file/0 random_file
+         
+         dir/0 (random.ascii/lower 4)
+         file/1 (# ! each (|>> (format dir/0 /)) random_file)
+         
+         .let [random_content (: (Random Binary)
+                                 (# ! each (|>> %.nat (# utf8.codec encoded)) random.nat))]
+         now random.instant
+         content/0 random_content
+         content/1 random_content
+         .let [library_content (|> (do try.monad
+                                     [file/0 (tar.path file/0)
+                                      file/1 (tar.path file/1)
+                                      content/0 (tar.content content/0)
+                                      content/1 (tar.content content/1)]
+                                     (in (|> (sequence.sequence {tar.#Normal [file/0 now export.mode export.ownership content/0]}
+                                                                {tar.#Normal [file/1 now export.mode export.ownership content/1]})
+                                             (format.result tar.writer))))
+                                   (try.else (binary.empty 0)))
+               library_content/0 (|> (do try.monad
+                                       [file/0 (tar.path file/0)
+                                        content/0 (tar.content content/0)]
+                                       (in (|> (sequence.sequence {tar.#Normal [file/0 now export.mode export.ownership content/0]})
+                                               (format.result tar.writer))))
+                                     (try.else (binary.empty 0)))
+               library_content/1 (|> (do try.monad
+                                       [file/1 (tar.path file/1)
+                                        content/1 (tar.content content/1)]
+                                       (in (|> (sequence.sequence {tar.#Normal [file/1 now export.mode export.ownership content/1]})
+                                               (format.result tar.writer))))
+                                     (try.else (binary.empty 0)))
+               library_content/-0 (|> (do try.monad
+                                        [file/0 (tar.path file/0)
+                                         content/0 (tar.content content/0)]
+                                        (in (|> (sequence.sequence {tar.#Contiguous [file/0 now export.mode export.ownership content/0]})
+                                                (format.result tar.writer))))
+                                      (try.else (binary.empty 0)))
+               library_content/-1 (|> (do try.monad
+                                        [file/0 (tar.path file/0)]
+                                        (in (|> (sequence.sequence {tar.#Symbolic_Link file/0})
+                                                (format.result tar.writer))))
+                                      (try.else (binary.empty 0)))
+               library_content/-2 (|> (do try.monad
+                                        [file/0 (tar.path file/0)]
+                                        (in (|> (sequence.sequence {tar.#Directory file/0})
+                                                (format.result tar.writer))))
+                                      (try.else (binary.empty 0)))
+               imported? (: (-> /.Import Bit)
+                            (function (_ it)
+                              (and (n.= 2 (dictionary.size it))
+                                   (|> it
+                                       (dictionary.value file/0)
+                                       (maybe#each (binary#= content/0))
+                                       (maybe.else false))
+                                   (|> it
+                                       (dictionary.value file/1)
+                                       (maybe#each (binary#= content/1))
+                                       (maybe.else false)))))]]
+        ($_ _.and
+            (in (do [! async.monad]
+                  [it/0 (do (try.with !)
+                          [.let [fs (file.mock /)]
+                           _ (# fs write library_content library/0)]
+                          (/.import fs (list library/0)))
+                   it/1 (do (try.with !)
+                          [.let [fs (file.mock /)]
+                           _ (# fs write library_content/0 library/0)
+                           _ (# fs write library_content/1 library/1)]
+                          (/.import fs (list library/0 library/1)))]
+                  (_.cover' [/.import]
+                            (and (|> it/0
+                                     (try#each imported?)
+                                     (try.else false))
+                                 (|> it/1
+                                     (try#each imported?)
+                                     (try.else false))))))
+            (in (do [! async.monad]
+                  [it (do (try.with !)
+                        [.let [fs (file.mock /)]
+                         _ (# fs write library_content library/0)
+                         _ (/.import fs (list library/0 library/0))]
+                        (in false))]
+                  (_.cover' [/.duplicate]
+                            (exception.otherwise (exception.match? /.duplicate) it))))
+            (in (do [! async.monad]
+                  [it/0 (do (try.with !)
+                          [.let [fs (file.mock /)]
+                           _ (# fs write library_content/-0 library/0)
+                           _ (/.import fs (list library/0))]
+                          (in false))
+                   it/1 (do (try.with !)
+                          [.let [fs (file.mock /)]
+                           _ (# fs write library_content/-1 library/0)
+                           _ (/.import fs (list library/0))]
+                          (in false))
+                   it/2 (do (try.with !)
+                          [.let [fs (file.mock /)]
+                           _ (# fs write library_content/-2 library/0)
+                           _ (/.import fs (list library/0))]
+                          (in false))]
+                  (_.cover' [/.useless_tar_entry]
+                            (and (exception.otherwise (exception.match? /.useless_tar_entry) it/0)
+                                 (exception.otherwise (exception.match? /.useless_tar_entry) it/1)
+                                 (exception.otherwise (exception.match? /.useless_tar_entry) it/2)))))
+            ))))
diff --git a/stdlib/source/test/lux/type/check.lux b/stdlib/source/test/lux/type/check.lux
index 9d38c6f6d..818441adf 100644
--- a/stdlib/source/test/lux/type/check.lux
+++ b/stdlib/source/test/lux/type/check.lux
@@ -731,7 +731,7 @@
     (_.cover [/.clean]
              (and (|> (do /.monad
                         [[var_id varT] /.var
-                         cleanedT (/.clean (type_shape varT))]
+                         cleanedT (/.clean (list) (type_shape varT))]
                         (in (type#= (type_shape varT)
                                     cleanedT)))
                       (/.result /.fresh_context)
@@ -740,7 +740,7 @@
                         [[var_id varT] /.var
                          [_ replacementT] /.existential
                          _ (/.check varT replacementT)
-                         cleanedT (/.clean (type_shape varT))]
+                         cleanedT (/.clean (list) (type_shape varT))]
                         (in (type#= (type_shape replacementT)
                                     cleanedT)))
                       (/.result /.fresh_context)