From: lewie <unknown>
Date: Sat, 14 Apr 2001 07:36:58 +0000 (+0000)
Subject: [project @ 2001-04-14 07:36:58 by lewie]
X-Git-Tag: Approximately_9120_patches~2156
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=8166bb6c76b9a240c732ae3b20300123f0f0ad61;p=ghc-hetmet.git

[project @ 2001-04-14 07:36:58 by lewie]
Fix a couple of bugs affecting implicit params.  With implicit params, you
can have a rho type w/o being a forall type.
---

diff --git a/ghc/compiler/typecheck/TcType.lhs b/ghc/compiler/typecheck/TcType.lhs
index f332114..2cee03e 100644
--- a/ghc/compiler/typecheck/TcType.lhs
+++ b/ghc/compiler/typecheck/TcType.lhs
@@ -188,7 +188,8 @@ fresh type variables, splits off the dictionary part, and returns the results.
 tcInstType :: TcType -> NF_TcM ([TcTyVar], TcThetaType, TcType)
 tcInstType ty
   = case splitForAllTys ty of
-	([],     _)   -> returnNF_Tc ([], [], ty) 	 -- Nothing to do
+	([],     rho) -> tcSplitRhoTy rho			`thenNF_Tc` \ (theta, tau) ->
+			 returnNF_Tc ([], theta, tau)
 	(tyvars, rho) -> tcInstTyVars tyvars			`thenNF_Tc` \ (tyvars', _, tenv)  ->
 			 tcSplitRhoTy (substTy tenv rho)	`thenNF_Tc` \ (theta, tau) ->
 			 returnNF_Tc (tyvars', theta, tau)
diff --git a/ghc/compiler/types/PprType.lhs b/ghc/compiler/types/PprType.lhs
index 6e4d5d0..273a067 100644
--- a/ghc/compiler/types/PprType.lhs
+++ b/ghc/compiler/types/PprType.lhs
@@ -22,7 +22,7 @@ import TypeRep		( Type(..), TyNote(..), Kind, liftedTypeKind ) -- friend
 import Type		( PredType(..), ThetaType,
 			  splitPredTy_maybe,
 			  splitForAllTys, splitSigmaTy, splitRhoTy,
-			  isDictTy, splitTyConApp_maybe, splitFunTy_maybe,
+			  isPredTy, isDictTy, splitTyConApp_maybe, splitFunTy_maybe,
                           predRepTy, isUTyVar
 			)
 import Var		( TyVar, tyVarKind )
@@ -189,8 +189,10 @@ ppr_ty ctxt_prec (FunTy ty1 ty2)
   -- so we mustn't use splitFunTys here.
   = maybeParen ctxt_prec fUN_PREC $
     sep [ ppr_ty fUN_PREC ty1
-        , ptext SLIT("->") <+> ppr_ty tOP_PREC ty2
+        , ptext arrow <+> ppr_ty tOP_PREC ty2
         ]
+  where arrow | isPredTy ty1 = SLIT("=>")
+	      | otherwise    = SLIT("->")
 
 ppr_ty ctxt_prec (AppTy ty1 ty2)
   = maybeParen ctxt_prec tYCON_PREC $