Better error reporting when analyzing variants.

5 files changed, 29 insertions, 20 deletions

diff --git a/stdlib/source/documentation/lux/control/security/capability.lux b/stdlib/source/documentation/lux/control/security/capability.lux
index 8d9c7f2ad..d328cabd3 100644
--- a/stdlib/source/documentation/lux/control/security/capability.lux
+++ b/stdlib/source/documentation/lux/control/security/capability.lux
@@ -20,9 +20,9 @@
                "Applies a capability against its required input."
                [(use capability input)])
 
-             ($.definition /.capability:
+             ($.definition /.capability
                "Defines a capability as a unique type, and a constructor for instances."
-               [(capability: (Can_Duplicate a)
+               [(capability (Can_Duplicate a)
                   (can_duplicate a [a a]))
                 
                 (let [capability (can_duplicate
diff --git a/stdlib/source/library/lux/control/security/capability.lux b/stdlib/source/library/lux/control/security/capability.lux
index 24e627960..48323d842 100644
--- a/stdlib/source/library/lux/control/security/capability.lux
+++ b/stdlib/source/library/lux/control/security/capability.lux
@@ -26,14 +26,14 @@
 (primitive .public (Capability brand input output)
   (-> input output)
 
-  (def .public (use capability input)
+  (def .public (use it input)
     (All (_ brand input output)
       (-> (Capability brand input output)
           input
           output))
-    ((representation capability) input))
+    ((representation it) input))
 
-  (def .public capability:
+  (def .public capability
     (syntax (_ [[export_policy declaration [forger input output]]
                 (|export|.parser
                  (all <>.and
@@ -45,20 +45,20 @@
            .let [[name vars] declaration]
            g!brand (at ! each (|>> %.code code.text)
                        (macro.symbol (format (%.symbol [this_module name]))))
-           .let [capability (` (..Capability (.Primitive (, g!brand)) (, input) (, output)))]]
+           .let [type (` (..Capability (.Primitive (, g!brand)) (, input) (, output)))]]
           (in (list (` (type (, export_policy)
                          (, (|declaration|.format declaration))
-                         (, capability)))
+                         (, type)))
                     (` (def (, (code.local forger))
                          (All ((, g!_) (,* (list#each code.local vars)))
                            (-> (-> (, input) (, output))
-                               (, capability)))
+                               (, type)))
                          (|>> as_expected)))
                     ))))))
 
-  (def .public (async capability)
+  (def .public (async it)
     (All (_ brand input output)
       (-> (Capability brand input (IO output))
           (Capability brand input (Async output))))
-    (abstraction (|>> ((representation capability)) async.future)))
+    (abstraction (|>> ((representation it)) async.future)))
   )
diff --git a/stdlib/source/library/lux/meta/compiler/language/lux/phase/analysis/complex.lux b/stdlib/source/library/lux/meta/compiler/language/lux/phase/analysis/complex.lux
index 2db7b161f..ec4a32d05 100644
--- a/stdlib/source/library/lux/meta/compiler/language/lux/phase/analysis/complex.lux
+++ b/stdlib/source/library/lux/meta/compiler/language/lux/phase/analysis/complex.lux
@@ -64,10 +64,18 @@
             ["Expression" (%.code code)])))]
 
   [invalid_variant_type]
-  [cannot_analyse_variant]
+  [cannot_analyse_sum]
   [cannot_infer_sum]
   )
 
+(exception .public (cannot_analyse_variant [type Type
+                                            tag Symbol
+                                            code Code])
+  (exception.report
+   (list ["Type" (%.type type)]
+         ["Tag" (%.symbol tag)]
+         ["Expression" (%.code code)])))
+
 (exception .public (cannot_repeat_slot [key Symbol
                                         record (List [Symbol Code])])
   (exception.report
@@ -104,7 +112,7 @@
       (do [! ///.monad]
         [expectedT (///extension.lifted meta.expected_type)
          expectedT' (/type.check (check.clean (list) expectedT))]
-        (/.with_exception ..cannot_analyse_variant [expectedT' lefts right? valueC]
+        (/.with_exception ..cannot_analyse_sum [expectedT' lefts right? valueC]
           (case expectedT
             {.#Sum _}
             (|> (analyse archive valueC)
@@ -184,7 +192,8 @@
         (in (/.variant [lefts right? (|> valueA+ list.head maybe.trusted)])))
 
       _
-      (..sum analyse lefts right? archive valueC))))
+      (/.with_exception ..cannot_analyse_variant [expectedT tag valueC]
+        (..sum analyse lefts right? archive valueC)))))
 
 (def (typed_product analyse expectedT archive members)
   (-> Phase Type Archive (List Code) (Operation Analysis))
diff --git a/stdlib/source/library/lux/world/db/jdbc.lux b/stdlib/source/library/lux/world/db/jdbc.lux
index 955335715..4c215de63 100644
--- a/stdlib/source/library/lux/world/db/jdbc.lux
+++ b/stdlib/source/library/lux/world/db/jdbc.lux
@@ -12,7 +12,7 @@
     [concurrency
      ["[0]" async (.only Async) (.use "[1]#[0]" monad)]]
     [security
-     ["!" capability (.only capability:)]]]
+     ["!" capability (.only capability)]]]
    [data
     ["[0]" product]
     [text
@@ -66,17 +66,17 @@
     #value input]))
 
 (with_template [<name> <forge> <output>]
-  [(capability: .public (<name> ! i)
+  [(capability .public (<name> ! i)
      (<forge> (Statement i) (! (Try <output>))))]
 
   [Can_Execute can_execute Nat]
   [Can_Insert  can_insert  (List ID)]
   )
 
-(capability: .public (Can_Query ! i o)
+(capability .public (Can_Query ! i o)
   (can_query [(Statement i) (Output o)] (! (Try (List o)))))
 
-(capability: .public (Can_Close !)
+(capability .public (Can_Close !)
   (can_close Any (! (Try Any))))
 
 (type .public (DB !)
diff --git a/stdlib/source/test/lux/control/security/capability.lux b/stdlib/source/test/lux/control/security/capability.lux
index d61e32bbe..ecc9d22ba 100644
--- a/stdlib/source/test/lux/control/security/capability.lux
+++ b/stdlib/source/test/lux/control/security/capability.lux
@@ -15,10 +15,10 @@
  [\\library
   ["[0]" /]])
 
-(/.capability: (Can_Shift a)
+(/.capability (Can_Shift a)
   (can_shift [a Nat] [a Nat]))
 
-(/.capability: Can_IO
+(/.capability Can_IO
   (can_io [] (IO Nat)))
 
 (def .public test
@@ -31,7 +31,7 @@
          pass_through (random.ascii 1)]
         (_.for [/.Capability]
                (all _.and
-                    (_.coverage [/.capability: /.use]
+                    (_.coverage [/.capability /.use]
                       (let [capability (..can_shift (function (_ [no_op raw])
                                                       [no_op (n.+ shift raw)]))
                             [untouched actual] (/.use capability [pass_through base])]