[GHC] #11343: Unable to infer type when using DuplicateRecordFields

[GHC]

#11343: Unable to infer type when using DuplicateRecordFields
-------------------------------------+-------------------------------------
        Reporter:  mpickering        |                Owner:  adamgundry
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.11
  checker)                           |
      Resolution:                    |             Keywords:  ORF
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by adamgundry):

 At the moment we permit `(aThing :: A) { a = 5 }` because there is a
 special rule that looks for a type signature on the record expression. We
 could have a similar rule that looks for a variable of known type, which
 would permit `aThing { a = 5 }`. We'd yet need another rule for `(A 10) {
 a = 5 }`; that one looks less useful to me. None of this is doing true
 inference, though.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11343#comment:5>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler