Better pretty-printing for TvSubst

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index 872feb0..fdcec30 100644 (file)
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -1135,9 +1135,9 @@ zip_ty_env tvs      tys      env   = pprTrace "Var/Type length mismatch: " (ppr
 
 instance Outputable TvSubst where
   ppr (TvSubst ins env) 
-    = sep[ ptext SLIT("<TvSubst"),
-          nest 2 (ptext SLIT("In scope:") <+> ppr ins), 
-          nest 2 (ptext SLIT("Env:") <+> ppr env) ]
+    = brackets $ sep[ ptext SLIT("TvSubst"),
+                     nest 2 (ptext SLIT("In scope:") <+> ppr ins), 
+                     nest 2 (ptext SLIT("Env:") <+> ppr env) ]
 \end{code}
 
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