Improve error message (imported from Prelude at Implicit import declaration)

diff --git a/compiler/basicTypes/RdrName.lhs b/compiler/basicTypes/RdrName.lhs
index 3c6cd77..e99a41e 100644 (file)
--- a/compiler/basicTypes/RdrName.lhs
+++ b/compiler/basicTypes/RdrName.lhs
@@ -45,7 +45,7 @@ import Module   ( ModuleName, mkModuleNameFS, Module, moduleName )
 import Name    ( Name, NamedThing(getName), nameModule, nameParent_maybe,
                  nameOccName, isExternalName, nameSrcLoc )
 import Maybes  ( mapCatMaybes )
-import SrcLoc  ( isGoodSrcLoc, SrcSpan )
+import SrcLoc  ( isGoodSrcLoc, isGoodSrcSpan, SrcSpan )
 import FastString ( FastString )
 import Outputable
 import Util    ( thenCmp )
@@ -538,7 +538,10 @@ ppr_defn loc | isGoodSrcLoc loc = parens (ptext SLIT("defined at") <+> ppr loc)
             | otherwise        = empty
 
 instance Outputable ImportSpec where
-   ppr imp_spec@(ImpSpec imp_decl _)
-     = ptext SLIT("imported from") <+> ppr (is_mod imp_decl) 
-       <+> ptext SLIT("at") <+> ppr (importSpecLoc imp_spec)
+   ppr imp_spec
+     = ptext SLIT("imported from") <+> ppr (importSpecModule imp_spec) 
+       <+> if isGoodSrcSpan loc then ptext SLIT("at") <+> ppr loc
+                                else empty
+     where
+       loc = importSpecLoc imp_spec
 \end{code}