#12641: Indentation works differently for multi-way if than for guards when using comma-separate view patterns -------------------------------------+------------------------------------- Reporter: ahmadsalim | Owner: Type: bug | Status: new Priority: lowest | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Other Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When trying to parse the following piece of code: {{{#!hs {-# LANGUAGE MultiWayIf #-} module Test where data AB = A | B aAndB :: AB -> AB -> Bool aAndB ab1 ab2 = if | A <- ab1 , B <- ab2 -> True | otherwise -> False }}} I get the following error {{{ test.hs:9:6: error: parse error (possibly incorrect indentation or mismatched brackets) }}} This is as currently is inconsistent with how guards are parsed, e.g.: {{{#!hs aAndB2 :: AB -> AB -> Bool aAndB2 ab1 ab2 | A <- ab1 , B <- ab2 = True | otherwise = False }}} works perfectly fine. Note, that if I indent the comma a bit in aAndB, the following will parse correctly: {{{#!hs aAndB :: AB -> AB -> Bool aAndB ab1 ab2 = if | A <- ab1 , B <- ab2 -> True | otherwise -> False }}} Of course, this is far from a major issue, but I thought it would probably be beneficial to report the issue nonetheless. It also looks likely less neat with the comma indented. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12641 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler