#7354: Panic with recursion-schemes package and unit
------------------------+---------------------------------------------------
Reporter: amplitwist | Owner:
Type: bug | Status: new
Priority: normal | Component: GHCi
Version: 7.6.1 | Keywords:
Os: Linux | Architecture: x86_64 (amd64)
Failure: GHCi crash | Testcase:
Blockedby: | Blocking:
Related: |
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Comment(by guest):
I reduced your testcase:
1. Create file `T.hs`
{{{
{-# LANGUAGE TypeFamilies, FlexibleContexts #-}
module T where
type family Base t :: * -> *
class Unfoldable t where
embed :: Base t t -> t
}}}
2. Create file `R.hs`
{{{
module R where
import T
foo = embed ()
}}}
3. Run `ghci R.hs`, and observe
{{{
*R> foo
<interactive>:2:1:
Can't find interface-file declaration for variable foo
Probable cause: bug in .hi-boot file, or inconsistent .hi file
Use -ddump-if-trace to get an idea of which file caused the error
In the expression: foo
In an equation for `it': it = foo
*R> embed ()
ghc: panic! (the 'impossible' happened)
(GHC version 7.6.1 for x86_64-unknown-linux):
nameModule
<<details unavailable>>
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7354#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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