#3692: TcTyFuns.flattenType: unexpected PredType
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Reporter: cdfh | Owner:
Type: bug | Status: closed
Priority: normal | Milestone:
Component: Compiler | Version: 6.10.4
Resolution: fixed | Keywords: TcTyFuns PredType panic
Difficulty: | Os: Linux
Testcase: | Architecture: x86_64 (amd64)
Failure: Compile-time crash |
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Changes (by igloo):
* status: new => closed
* resolution: => fixed
Comment:
Thanks for the report. I can reproduce this in 6.10.4, but HEAD and 6.12
say:
{{{
vi.hs:6:10:
Could not deduce (Bar ((Bar a) => a)) from the context ()
arising from an expression type signature at vi.hs:6:10-29
Possible fix:
add (Bar ((Bar a) => a)) to the context of
the type signature for `foo'
or add an instance declaration for (Bar ((Bar a) => a))
In the first argument of `id', namely `(undefined :: Foo a b)'
In the expression: id (undefined :: Foo a b)
In the definition of `foo': foo = id (undefined :: Foo a b)
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3692#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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