X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcType.lhs;h=e0e76493ee06f39674de69c00a7c2e9b3603d9e8;hb=aedb94f5f220b5e442b23ecc445fd38c8d9b6ba0;hp=fe5ea396924950e3914ff2bc65beffc619e42ebd;hpb=654d07dd0fb679d014ac363e13c004b0086d0d6e;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index fe5ea39..e0e7649 100644
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -965,10 +965,13 @@ isSigmaTy (FunTy a _)    = isPredTy a
 isSigmaTy _              = False
 
 isOverloadedTy :: Type -> Bool
+-- Yes for a type of a function that might require evidence-passing
+-- Used only by bindInstsOfLocalFuns/Pats
+-- NB: be sure to check for type with an equality predicate; hence isCoVar
 isOverloadedTy ty | Just ty' <- tcView ty = isOverloadedTy ty'
-isOverloadedTy (ForAllTy _ ty) = isOverloadedTy ty
-isOverloadedTy (FunTy a _)     = isPredTy a
-isOverloadedTy _               = False
+isOverloadedTy (ForAllTy tv ty) = isCoVar tv || isOverloadedTy ty
+isOverloadedTy (FunTy a _)      = isPredTy a
+isOverloadedTy _                = False
 
 isPredTy :: Type -> Bool	-- Belongs in TcType because it does 
 				-- not look through newtypes, or predtypes (of course)