[project @ 2001-08-24 12:47:04 by simonpj]

Improve error message for mis-matched contexts

diff --git a/ghc/compiler/typecheck/TcBinds.lhs b/ghc/compiler/typecheck/TcBinds.lhs
index 4a1203a..9ace4e4 100644 (file)
--- a/ghc/compiler/typecheck/TcBinds.lhs
+++ b/ghc/compiler/typecheck/TcBinds.lhs
@@ -780,9 +780,10 @@ valSpecSigCtxt v ty
 sigContextsErr = ptext SLIT("Mismatched contexts")
 
 sigContextsCtxt s1 s2
-  = hang (hsep [ptext SLIT("When matching the contexts of the signatures for"), 
-               quotes (ppr s1), ptext SLIT("and"), quotes (ppr s2)])
-        4 (ptext SLIT("(the signature contexts in a mutually recursive group should all be identical)"))
+  = vcat [ptext SLIT("When matching the contexts of the signatures for"), 
+         nest 2 (vcat [ppr s1 <+> dcolon <+> ppr (idType s1),
+                       ppr s2 <+> dcolon <+> ppr (idType s2)]),
+         ptext SLIT("The signature contexts in a mutually recursive group should all be identical")]
 
 -----------------------------------------------
 unliftedBindErr flavour mbind