Fix meet check when ForAll is on right

paf31 · paf31 · commit d1cdc986799c · 2014-09-17T17:15:21.000-05:00
diff --git a/examples/passing/IfThenElseMaybe.purs b/examples/passing/IfThenElseMaybe.purs
@@ -2,6 +2,8 @@ module Main where
 
 data Maybe a = Nothing | Just a
 
-test = if true then Just 10 else Nothing
+test1 = if true then Just 10 else Nothing
+
+test2 = if true then Nothing else Just 10
 
 main = Debug.Trace.trace "Done"
diff --git a/src/Language/PureScript/TypeChecker/Types.hs b/src/Language/PureScript/TypeChecker/Types.hs
@@ -1131,7 +1131,9 @@ subsumes' val ty1 ty2 = do
 -- TODO: handle constrained types
 --
 meet :: Expr -> Expr -> Type -> Type -> UnifyT Type Check (Expr, Expr, Type)
-meet e1 e2 t1@(ForAll _ _ _) t2 = meet e1 e2 t1 t2
+meet e1 e2 (ForAll ident t1 _) t2 = do
+  t1' <- replaceVarWithUnknown ident t1
+  meet e1 e2 t1' t2
 meet e1 e2 t1 (ForAll ident t2 _) = do
   t2' <- replaceVarWithUnknown ident t2
   meet e1 e2 t1 t2'
