feat(type-infer): Add a new error message in the case of multiple tya…

…pps being detected (which shouldn't happen?)
ElaraLang · Jun 1, 2024 · 7486ea1 · 7486ea1
1 parent 8503c23
commit 7486ea1
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diff --git a/src/Elara/TypeInfer/Error.hs b/src/Elara/TypeInfer/Error.hs
@@ -154,6 +154,7 @@ data TypeInferenceError where
     KindInferError :: KindInferError -> TypeInferenceError
     PartiallyAppliedConstructorPattern :: HasCallStack => TypeInferenceError
     NotCustomType :: HasCallStack => SourceRegion -> Type SourceRegion -> TypeInferenceError
+    AmbiguousTypeApplication :: HasCallStack => SourceRegion -> [Type SourceRegion] -> TypeInferenceError
 
 deriving instance Show TypeInferenceError
 

diff --git a/src/Elara/TypeInfer/Infer.hs b/src/Elara/TypeInfer/Infer.hs
@@ -1372,11 +1372,13 @@ check expr@(Expr (Located exprLoc _, _)) t = debug ("check: " <> showPretty expr
         -}
         case _At of
             Type.Forall{} -> do
+                debug' $ "applicableTyApp: " <> showPretty (_At, t) <> " => " <> showPretty (Type.applicableTyApp _At t)
                 case _At `Type.applicableTyApp` t of
                     [] -> pure _A
-                    (tApp : _) ->
+                    [tApp] ->
                         -- insert type application from instantiating the forall
                         pure $ Expr (Located exprLoc (TypeApplication _A tApp), _At `Type.instantiate` t)
+                    more -> throw $ AmbiguousTypeApplication exprLoc more
             _ -> pure _A
 
 {- | This corresponds to the judgment: