[GHC] #13853: TypeApplications and record syntax don't mix

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Tue Jun 20 16:36:47 UTC 2017


#13853: TypeApplications and record syntax don't mix
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
                                     |  TypeApplications
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Description changed by RyanGlScott:

@@ -24,7 +24,0 @@
- λ> (Identity @Int) { runIdentity = 42 }
-
- <interactive>:7:1: error:
-     • Couldn't match expected type ‘Identity a0’
-                   with actual type ‘Int -> Identity Int’
-     • In the expression: (Identity @Int) {runIdentity = 42}
-       In an equation for ‘it’: it = (Identity @Int) {runIdentity = 42}

New description:

 Let's fire up GHCi:

 {{{
 $ ~/Software/ghc-8.2.0.20170507/bin/ghci
 GHCi, version 8.2.0.20170507: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from /Users/rscott/.ghci
 λ> :set -XTypeApplications -fprint-explicit-foralls
 λ> import Data.Functor.Identity
 }}}

 I can use `TypeApplications` on `Identity` like so:

 {{{
 λ> Identity @Int 42
 Identity 42
 }}}

 But not if I try to use record syntax:

 {{{
 λ> Identity @Int { runIdentity = 42 }

 <interactive>:4:15: error: parse error on input ‘{’
 }}}

--

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13853#comment:1>
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