X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnTypes.lhs;h=e209036e5eb1d1878f822988273cc4c366d57a9e;hp=d7d435ce974d97c2d0df0ad116ef0939b78539c6;hb=cbc86d748d5f7b5ad5503c9e87c0b5c0402f27bc;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1

diff --git a/compiler/rename/RnTypes.lhs b/compiler/rename/RnTypes.lhs
index d7d435c..e209036 100644
--- a/compiler/rename/RnTypes.lhs
+++ b/compiler/rename/RnTypes.lhs
@@ -416,7 +416,14 @@ checkPrecMatch True op (MatchGroup ms _)
       = checkPrec op (unLoc p1) False	`thenM_`
         checkPrec op (unLoc p2) True
 
-    check _ = panic "checkPrecMatch"
+    check _ = return ()	
+	-- This can happen.  Consider
+	--	a `op` True = ...
+	--	op          = ...
+	-- The infix flag comes from the first binding of the group
+	-- but the second eqn has no args (an error, but not discovered
+	-- until the type checker).  So we don't want to crash on the
+	-- second eqn.
 
 checkPrec op (ConPatIn op1 (InfixCon _ _)) right
   = lookupFixityRn op		`thenM` \  op_fix@(Fixity op_prec  op_dir) ->