[GHC] #13644: overloaded name used in record pattern matching leads to panic! (the 'impossible' happened) in ghc

4 May 2017


      #13644: overloaded name used in record pattern matching leads to panic!  (the
'impossible' happened) in ghc
-------------------------------------+-------------------------------------
           Reporter:  pjljvdlaar     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.2
           Keywords:                 |  Operating System:  Windows
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash or panic
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 In Haskell,
 1. The scope of definitions can be controled.
 2. The same name can be used to define both a function and a field of
 record.
 3. The user can use that name in record pattern matching when only the
 function is within scope. For example
 {{{
 FuncId{ name = nm }
 }}}
 resulting in the following bug

 {{{
 [38 of 39] Compiling TxsUtils         ( src\TxsUtils.hs, .stack-
 work\dist\1f7101f2\build\Txs
 Utils.o )
 ghc.EXE: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-mingw32):
         translateConPatVec: lookup

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13644
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler