[GHC] #14313: “Result signatures are no longer supported in pattern matches” lost

[GHC]

#14313: “Result signatures are no longer supported in pattern matches” lost
-------------------------------------+-------------------------------------
           Reporter:  nomeata        |             Owner:  (none)
               Type:  task           |            Status:  new
           Priority:  low            |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #2310
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 This commit (b98ff25f4c8cb4bf18b784c848fabaaa6e4b11b8) from two years ago
 broke the error message (at least according to when `T2310.stderr` was
 modified):

 {{{
 T2310.hs:5:22:
     Illegal result type signature ‘a’
       Result signatures are no longer supported in pattern matches
     In a lambda abstraction: \ x :: a -> (x :: a)
 }}}
 that was displayed previously.

 Either we do want that error message (then this is a bug) or we don’t care
 about this error message any more, then probably we can remove the
 `m_type` field of `Match` in `HsExpr`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14313>
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