X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypes%2FFamInstEnv.lhs;fp=compiler%2Ftypes%2FFamInstEnv.lhs;h=5b4374afa2e834cad5c9f283e805baf5d82a4462;hp=894da340c7e245dc013063932a7da1d2622769d0;hb=d7fb8d371d3228774331a67db8da805b2d68f1c4;hpb=d872133bb986dbd15959cbb14504bf9a863e3e4a

diff --git a/compiler/types/FamInstEnv.lhs b/compiler/types/FamInstEnv.lhs
index 894da34..5b4374a 100644
--- a/compiler/types/FamInstEnv.lhs
+++ b/compiler/types/FamInstEnv.lhs
@@ -84,7 +84,12 @@ instance Outputable FamInst where
 pprFamInst :: FamInst -> SDoc
 pprFamInst famInst
   = hang (pprFamInstHdr famInst)
-	2 (ptext (sLit "--") <+> pprNameLoc (getName famInst))
+       2 (vcat [ ifPprDebug (ptext (sLit "Coercion axiom:") <+> pp_ax)
+               , ptext (sLit "--") <+> pprNameLoc (getName famInst)])
+  where
+    pp_ax = case tyConFamilyCoercion_maybe (fi_tycon famInst) of
+              Just ax -> ppr ax
+              Nothing -> ptext (sLit "<not there!>")
 
 pprFamInstHdr :: FamInst -> SDoc
 pprFamInstHdr (FamInst {fi_tycon = rep_tc})