X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FInst.lhs;h=a11efe05919dc26dfe1f66edf931f1b703028083;hb=3ee928b370511b9889a581e3e34ebe7ea9376004;hp=b0fe5f95cb8116df90697e653ea26a6c69962637;hpb=0aa1d46a1e5c19553c410dc6ff65b29594a2499f;p=ghc-hetmet.git

diff --git a/compiler/typecheck/Inst.lhs b/compiler/typecheck/Inst.lhs
index b0fe5f9..a11efe0 100644
--- a/compiler/typecheck/Inst.lhs
+++ b/compiler/typecheck/Inst.lhs
@@ -161,12 +161,14 @@ ipNamesOfInst other		    	     = []
 tyVarsOfInst :: Inst -> TcTyVarSet
 tyVarsOfInst (LitInst {tci_ty = ty})  = tyVarsOfType  ty
 tyVarsOfInst (Dict {tci_pred = pred}) = tyVarsOfPred pred
-tyVarsOfInst (Method {tci_oid = id, tci_tys = tys}) = tyVarsOfTypes tys `unionVarSet` idFreeTyVars id
+tyVarsOfInst (Method {tci_oid = id, tci_tys = tys}) = tyVarsOfTypes tys `unionVarSet` varTypeTyVars id
 				 -- The id might have free type variables; in the case of
 				 -- locally-overloaded class methods, for example
 tyVarsOfInst (ImplicInst {tci_tyvars = tvs, tci_given = givens, tci_wanted = wanteds})
-  = (tyVarsOfInsts givens `unionVarSet` tyVarsOfInsts wanteds) `minusVarSet` mkVarSet tvs
-
+  = (tyVarsOfInsts givens `unionVarSet` tyVarsOfInsts wanteds) 
+    `minusVarSet` mkVarSet tvs
+    `unionVarSet` unionVarSets (map varTypeTyVars tvs)
+		-- Remember the free tyvars of a coercion
 
 tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts
 tyVarsOfLIE   lie   = tyVarsOfInsts (lieToList lie)
@@ -333,11 +335,10 @@ mkPredName uniq loc pred_ty
 	    IParam ip  _ -> getOccName (ipNameName ip)
 	    EqPred ty  _ -> mkEqPredCoOcc baseOcc
 	      where
-		-- we use the outermost tycon of the lhs, which must be a type
-		-- function, as the base name for an equality
+		-- we use the outermost tycon of the lhs, if there is one, to
+		-- improve readability of Core code
 	        baseOcc = case splitTyConApp_maybe ty of
-			    Nothing      -> 
-			      pprPanic "Inst.mkPredName:" (ppr ty)
+			    Nothing      -> mkOccName tcName "$"
                             Just (tc, _) -> getOccName tc
 \end{code}
 
@@ -752,7 +753,7 @@ lookupSimpleInst (Dict {tci_pred = pred, tci_loc = loc})
     	(theta, _) = tcSplitPhiTy dfun_rho
 	src_loc	   = instLocSpan loc
 	dfun	   = HsVar dfun_id
-	tys	   = map (substTyVar tenv') tyvars
+	tys	   = substTyVars tenv' tyvars
     ; if null theta then
     	returnM (GenInst [] (L src_loc $ HsWrap (mkWpTyApps tys) dfun))
       else do