#4166: unsafeCoerce#'s kind is not as liberal enough to inspect tag bits.
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Reporter: ekmett | Owner:
Type: feature request | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 6.12.3
Resolution: worksforme | Keywords:
Difficulty: | Os: Unknown/Multiple
Testcase: | Architecture: Unknown/Multiple
Failure: None/Unknown |
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Changes (by simonmar):
* status: new => closed
* resolution: => worksforme
Comment:
Happily, this already works.
{{{
Prelude> import GHC.Exts
Prelude GHC.Exts> let x = I# (unsafeCoerce# True :: Int#)
Prelude GHC.Exts> x
1098195192
}}}
it works because `unsafeCoerce#` is not really a primop at all, but a
built-in identifier, and the type variables have the "open" kind (can be
instantiated by any type at all).
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4166#comment:2>
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