Signature type variables must not be instantiated with tycons

[ghc-hetmet.git] / compiler / typecheck / TcUnify.lhs

diff --git a/compiler/typecheck/TcUnify.lhs b/compiler/typecheck/TcUnify.lhs
index 4a5b2cc..99cd7b9 100644 (file)
--- a/compiler/typecheck/TcUnify.lhs
+++ b/compiler/typecheck/TcUnify.lhs
@@ -142,7 +142,7 @@ subFunTys error_herald n_pats res_ty thing_inside
               else loop n args_so_far (FunTy arg_ty' res_ty') }
 
     loop n args_so_far (TyVarTy tv)
-        | not (isImmutableTyVar tv)
+        | isTyConableTyVar tv
        = do { cts <- readMetaTyVar tv 
             ; case cts of
                 Indirect ty -> loop n args_so_far ty
@@ -196,7 +196,7 @@ boxySplitTyConApp tc orig_ty
       = loop (n_req - 1) (arg:args_so_far) fun
 
     loop n_req args_so_far (TyVarTy tv)
-      | not (isImmutableTyVar tv)
+      | isTyConableTyVar tv
       = do { cts <- readMetaTyVar tv
           ; case cts of
               Indirect ty -> loop n_req args_so_far ty
@@ -232,7 +232,7 @@ boxySplitAppTy orig_ty
       = return (fun_ty, arg_ty)
 
     loop (TyVarTy tv)
-      | not (isImmutableTyVar tv)
+      | isTyConableTyVar tv
       = do { cts <- readMetaTyVar tv
           ; case cts of
               Indirect ty -> loop ty