X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=67f2945464d1eb9ce11303ba63a2a4952fba18fc;hb=5822cb8d13aa3c05d2b46b4510c13d94b902eb21;hp=92c7958d26c6fd975ce651b65469f9bf1377e82c;hpb=f4510d27c5883fe7e8570f4dd49d45a8b0122f2c;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs
index 92c7958..67f2945 100644
--- a/compiler/typecheck/TcClassDcl.lhs
+++ b/compiler/typecheck/TcClassDcl.lhs
@@ -425,7 +425,7 @@ mkMethId origin clas sel_id inst_tys
 	rho_ty	     = ASSERT( length tyvars == length inst_tys )
 		       substTyWith tyvars inst_tys rho
 	(preds,tau)  = tcSplitPhiTy rho_ty
-        first_pred   = head preds
+        first_pred   = ASSERT( not (null preds)) head preds
     in
 	-- The first predicate should be of form (C a b)
 	-- where C is the class in question
@@ -452,8 +452,7 @@ mkMethId origin clas sel_id inst_tys
 	getSrcSpanM			`thenM` \ loc ->
 	let 
 	    real_tau = mkPhiTy (tail preds) tau
-	    meth_id  = mkUserLocal (getOccName sel_id) uniq real_tau 
-			(srcSpanStart loc) --TODO
+	    meth_id  = mkUserLocal (getOccName sel_id) uniq real_tau loc
 	in
 	returnM (Nothing, meth_id)
 
@@ -529,7 +528,7 @@ mkDefMethRhs origin clas inst_tys sel_id loc GenDefMeth
 	  -- case we require that the instance decl is for a single-parameter
 	  -- type class with type variable arguments:
 	  --	instance (...) => C (T a b)
-    clas_tyvar    = head (classTyVars clas)
+    clas_tyvar    = ASSERT (not (null (classTyVars clas))) head (classTyVars clas)
     Just tycon	  = maybe_tycon
     maybe_tycon   = case inst_tys of 
 			[ty] -> case tcSplitTyConApp_maybe ty of
@@ -707,7 +706,7 @@ mkGenericInstance clas (hs_ty, binds)
 	-- Make the dictionary function.
     getSrcSpanM						`thenM` \ span -> 
     getOverlapFlag					`thenM` \ overlap_flag -> 
-    newDFunName clas [inst_ty] (srcSpanStart span)	`thenM` \ dfun_name ->
+    newDFunName clas [inst_ty] span             	`thenM` \ dfun_name ->
     let
 	inst_theta = [mkClassPred clas [mkTyVarTy tv] | tv <- tyvars]
 	dfun_id    = mkDictFunId dfun_name tyvars inst_theta clas [inst_ty]
@@ -727,15 +726,15 @@ mkGenericInstance clas (hs_ty, binds)
 tcAddDeclCtxt decl thing_inside
   = addErrCtxt ctxt thing_inside
   where
-     thing = case decl of
-	   	ClassDecl {}		  -> "class"
-		TySynonym {}		  -> "type synonym"
-		TyFunction {}		  -> "type function signature"
-		TyData {tcdND = NewType}  -> "newtype" ++ maybeSig
-		TyData {tcdND = DataType} -> "data type" ++ maybeSig
+     thing | isClassDecl decl  = "class"
+	   | isTypeDecl decl   = "type synonym" ++ maybeInst
+	   | isDataDecl decl   = if tcdND decl == NewType 
+				 then "newtype" ++ maybeInst
+				 else "data type" ++ maybeInst
+	   | isFamilyDecl decl = "family"
 
-     maybeSig | isKindSigDecl decl = " signature"
-	      | otherwise	   = ""
+     maybeInst | isFamInstDecl decl = " instance"
+	       | otherwise          = ""
 
      ctxt = hsep [ptext SLIT("In the"), text thing, 
 		  ptext SLIT("declaration for"), quotes (ppr (tcdName decl))]
@@ -767,7 +766,7 @@ badGenericInstance sel_id because
 notSimple inst_tys
   = vcat [ptext SLIT("because the instance type(s)"), 
 	  nest 2 (ppr inst_tys),
-	  ptext SLIT("is not a simple type of form (T a b c)")]
+	  ptext SLIT("is not a simple type of form (T a1 ... an)")]
 
 notGeneric tycon
   = vcat [ptext SLIT("because the instance type constructor") <+> quotes (ppr tycon) <+>