[GHC] #760: Template Haskell doesn't like scoped type variables

[GHC]

#760: Template Haskell doesn't like scoped type variables
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  Reporter:  rl at cse.unsw.edu.au  |          Owner:       
      Type:  bug                 |         Status:  new  
  Priority:  normal              |      Milestone:       
 Component:  Compiler            |        Version:  6.4.2
  Severity:  normal              |     Resolution:       
  Keywords:                      |             Os:  Linux
Difficulty:  Unknown             |   Architecture:  x86  
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Comment (by simonpj):

 Template Haskell originally only supported Haskell 98, but various non-H98
 extensions have since been added.  Apparently, TH patterns can contain
 type signatures (I didn't know that), but there does not seem to be any
 support for lexical scoping of type variables.

 Since GHC itself is in a state of flux wrt lexically scoped type
 variables, I'm not going to fix this now. I would love some TH enthusiast
 to take it on.

 Meanwhile, just avoid type signatures in patterns.

 Simon

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/760>
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