[GHC] #700: Inconsistent typechecking of pattern match in function binding

[GHC]

#700: Inconsistent typechecking of pattern match in function binding
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  Reporter:  guest     |          Owner:         
      Type:  bug       |         Status:  new    
  Priority:  lowest    |      Milestone:         
 Component:  Compiler  |        Version:  6.4.1  
  Severity:  normal    |     Resolution:         
  Keywords:            |             Os:  Unknown
Difficulty:  Unknown   |   Architecture:  Unknown
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Changes (by simonpj):

  * priority:  normal => lowest

Comment:

 Yes, this is a little-used feature that I removed subsequent to GHC 6.4.

 Implementing it requires instantiation inside patterns, which was jolly
 tricky to implement, and all the more so when combined with GADTs etc.
 And the pain just didn't seem worth the gain; are you really going to have
 arguments with type (forall a. Maybe a)?

 Bottom line: I don't propose to change this unless there are some pretty
 convincing examples of how useful it'd be.  I'm guessing they are hard to
 find, but I could be wrong.

 I'll leave this open, but with verylow priority

 Simon

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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/700>
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