[project @ 1997-07-05 02:28:15 by sof]

err msgs improved

diff --git a/ghc/compiler/typecheck/TcSimplify.lhs b/ghc/compiler/typecheck/TcSimplify.lhs
index 0c52f1d..27e54e6 100644 (file)
--- a/ghc/compiler/typecheck/TcSimplify.lhs
+++ b/ghc/compiler/typecheck/TcSimplify.lhs
@@ -27,7 +27,7 @@ import Inst           ( lookupInst, lookupSimpleInst,
                          matchesInst, instToId, instBindingRequired,
                          instCanBeGeneralised, newDictsAtLoc,
                          pprInst,
-                         Inst(..), SYN_IE(LIE), zonkLIE, emptyLIE,
+                         Inst(..), SYN_IE(LIE), zonkLIE, emptyLIE, pprLIE, pprLIEInFull,
                          plusLIE, unitLIE, consLIE, InstOrigin(..),
                          OverloadedLit )
 import TcEnv           ( tcGetGlobalTyVars )
@@ -717,18 +717,23 @@ genCantGenErr insts sty   -- Can't generalise these Insts
 \end{code}
 
 \begin{code}
-ambigErr insts sty
-  = hang (ptext SLIT("Ambiguous overloading"))
-       4 (vcat (map (pprInst sty) insts))
+ambigErr dicts sty
+  = sep [text "Ambiguous context" <+> pprLIE sty lie,
+        nest 4 (pprLIEInFull sty lie)
+    ]
+  where
+    lie = listToBag dicts      -- Yuk
 \end{code}
 
 @reduceErr@ complains if we can't express required dictionaries in
 terms of the signature.
 
 \begin{code}
-reduceErr insts sty
-  = hang (text "Context required by inferred type, but missing on a type signature")
-       4 (vcat (map (pprInst sty) (bagToList insts)))
+reduceErr lie sty
+  = sep [text "Context" <+> pprLIE sty lie,
+        nest 4 (text "required by inferred type, but missing on a type signature"),
+        nest 4 (pprLIEInFull sty lie)
+    ]
 \end{code}