Panic in GHCi when using :print
When using names generated by :print, GHCi panics sometimes. According to #ghc, this is reproducible on x86_64-apple-darwin as well, but is not an issue in 7.6.3 x86_64 linux.
> let a = [1]
> :print a
a = (_t1::Num t => [t])
> :t _t1
ghc: panic! (the 'impossible' happened)
(GHC version 7.8.2 for x86_64-unknown-linux):
tcTyVarDetails t{tv avD} [tv]
> _t1
<same panic>
From playing around with it a bit, this seems to have something to do with polymorphic values.
-- No panic
> let a = [1 :: Int]
> let a = 1 :: Int
> let a = "hello"
-- Panic
> let a = [1]
> let a = 1
> let a = "hello" -- With -XOverloadedStrings
Trac metadata
Trac field | Value |
---|---|
Version | 7.8.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | GHCi |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | hvr |
Operating system | |
Architecture |