[project @ 1999-11-05 10:09:36 by simonmar]

Allow this syntax on the lhs:

	(e1 `op` e2) e3 = ...

(bug reported by Ralf Hinze).

Add a test for it.

ghc/compiler/parser/ParseUtil.lhs

@@ -335,8 +335,8 @@ checkValDef lhs opt_sig grhss loc
 
 -- A variable binding is parsed as an RdrNamePatBind.
 
-isFunLhs (OpApp l (HsVar op) fix r) []  | not (isRdrDataCon op)
-			  	= Just (op, True, [l,r])
+isFunLhs (OpApp l (HsVar op) fix r) es  | not (isRdrDataCon op)
+			  	= Just (op, True, (l:r:es))
 isFunLhs (HsVar f) es@(_:_)  | not (isRdrDataCon f)
 			 	= Just (f,False,es)
 isFunLhs (HsApp f e) es 	= isFunLhs f (e:es)

ghc/compiler/rename/RnExpr.lhs

@@ -684,7 +684,8 @@ checkPrecMatch :: Bool -> Name -> RenamedMatch -> RnMS ()
 checkPrecMatch False fn match
   = returnRn ()
 
-checkPrecMatch True op (Match _ [p1,p2] _ _)
+checkPrecMatch True op (Match _ (p1:p2:_) _ _)
+	-- True indicates an infix lhs
   = getModeRn 		`thenRn` \ mode ->
 	-- See comments with rnExpr (OpApp ...)
     case mode of

ghc/tests/reader/should_compile/read026.hs

+module ShouldCompile where
+
+(<>)          :: (a -> Maybe b) -> (b -> Maybe c) -> (a -> Maybe c)
+(m1 <> m2) a1	=  case m1 a1 of
+                      Nothing -> Nothing
+                      Just a2 -> m2 a2