[GHC] #3409: type variable out of scope in worker/wrapper transformation

[GHC]

#3409: type variable out of scope in worker/wrapper transformation
-----------------------------+----------------------------------------------
Reporter:  judahj            |          Owner:                  
    Type:  bug               |         Status:  new             
Priority:  normal            |      Component:  Compiler        
 Version:  6.10.3            |       Severity:  normal          
Keywords:                    |       Testcase:                  
      Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
-----------------------------+----------------------------------------------
 I ran into a bug while using type families in an array library that I'm
 writing.  The original error looked something like:
 {{{
 Declaration for $wslice:
   Iface type variable out of scope:  s
 }}}

 I've tried to strip down the code as much as possible into the attached
 cabal package with two modules.  The package  builds itself with -dcore-
 lint and -O2; so just running `cabal install` inside of the package should
 cause a Core Lint error.

 Let me know if there's any more information I can provide to help diagnose
 this issue.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3409>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler