Improve error-message output slightly

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index e96fdd4..636ee0e 100644 (file)
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -457,7 +457,7 @@ pprSkolTvBinding tv
     ppr_details (MetaTv (SigTv info) _) = ppr_skol info
     ppr_details (SkolemTv info)                = ppr_skol info
 
     ppr_details (MetaTv (SigTv info) _) = ppr_skol info
     ppr_details (SkolemTv info)                = ppr_skol info
 

-    ppr_skol UnkSkol       = empty     -- Unhelpful; omit
+    ppr_skol UnkSkol       = ptext SLIT("is an unknown type variable") -- Unhelpful

     ppr_skol RuntimeUnkSkol = ptext SLIT("is an unknown runtime type")
     ppr_skol info           = sep [ptext SLIT("is a rigid type variable bound by"),
                                   sep [pprSkolInfo info, 
     ppr_skol RuntimeUnkSkol = ptext SLIT("is an unknown runtime type")
     ppr_skol info           = sep [ptext SLIT("is a rigid type variable bound by"),
                                   sep [pprSkolInfo info,