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  • #4918

Closed
Open
Opened Jan 26, 2011 by Simon Peyton Jones@simonpjDeveloper

Rule matcher failing to look through an imported inlining

Pedro reported

module M1 where
  class MyEnum a where myEnum :: [a]
  instance MyEnum () where myEnum = [()]
 
module M2 where
  import M1

  f1 = map (\() -> 'p') [()]
  f2 = map (\() -> 'q') myEnum

The code for f1 was optimised (by rewrite rules) to

  f1 = ['p']

but the code for f2 wasn't.

Trac metadata
Trac field Value
Version 7.0.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
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Architecture
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Reference: ghc/ghc#4918