{
hunk ./compiler/parser/Parser.y.pp 1190
+							)])) }
+	| '|' aexp aexps opt_asig ralt
+			{% checkPatterns ($2 : reverse $3) >>= \ ps -> do
+         let lift (L _ (GRHS gd e)) = [_$_]
+              LL (GRHS gd (mkHsApp (nlHsVar $ mkUnqual dataName FSLIT("Match"))
+                           (mkHsApp (nlHsVar $ mkUnqual varName FSLIT("return"))
+                            e))) [_$_]
+         return (LL $ HsLam (mkMatchGroup [
+                  LL $ Match ps $4 (GRHSs (map lift (unLoc $5)) emptyLocalBinds),
+                  LL $ Match (map (const nlWildPat) ps) $4
+                  (GRHSs (unguardedRHS (nlHsApp (nlHsVar $ mkUnqual dataName FSLIT("Match"))
+                                        (nlHsApp (nlHsVar $ mkUnqual varName FSLIT("fail"))
+                                         (nlHsLit $ mkHsString "lambda-match failure"))))
+                  emptyLocalBinds
}