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  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #940

GADT + impredicative polymorphism => stack overflow

The following makes the GHC 6.6 type checker loop/overflow:

{-# OPTIONS_GHC -fglasgow-exts #-}
data Foo a b where F :: a -> Foo () a

bar :: Foo () (forall a.a) -> ()
bar (F _) = ()

ghc yields stack overflow, as does ghci. Reloading in GHCi leads to an infinite loop.

Trac metadata
Trac field Value
Version 6.6
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
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Blocking
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Operating system Unknown
Architecture Unknown
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