[GHC] #11662: Regression using NamedFieldPuns with qualified field names

1 Mar 2016


      #11662: Regression using NamedFieldPuns with qualified field names
-------------------------------------+-------------------------------------
           Reporter:  hesselink      |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1-rc2
           Keywords:                 |  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:
-------------------------------------+-------------------------------------
 I found a regression where code using the NamedFieldPuns extension and
 qualified field names doesn't compile with GHC 8 rc2, where it did with
 GHC 7.10.

 Minimal reproduction:

 {{{#!hs
 module Rec where

 data Rec = Rec { f :: Integer }

 --------------------

 {-# LANGUAGE NamedFieldPuns #-}
 module Main where

 import Rec (Rec (Rec))
 import qualified Rec

 g :: Rec -> Integer
 g (Rec { Rec.f }) = f
 }}}

 On GHC 8 this fails with:

 {{{
 Main.hs:6:10: error: Qualified name in binding position: Rec.f
 }}}

--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11662
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler