DeriveAnyClass + deriving Bifunctor causes GHC panic
Attempting the derive Bifunctor with DeriveAnyClass caused this message from GHC:
$ ghc Foo.hs
[1 of 1] Compiling Foo ( Foo.hs, Foo.o )
Var/Type length mismatch:
[a_an7, b_an8]
[]
Var/Type length mismatch:
[a_an7, b_an8]
[]
Var/Type length mismatch:
[a_an7, b_an8]
[]
Foo.hs:8:13:ghc: panic! (the 'impossible' happened)
(GHC version 7.10.2 for x86_64-apple-darwin):
tcTyVarDetails a_an7
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
The code:
{-# LANGUAGE DeriveAnyClass #-}
module Foo where
import Data.Bifunctor
data Blah a b = A a | B b
deriving (Bifunctor)
Change History (4)
Cc: |
dreixel added
|
Component: |
Compiler →
Compiler (Type checker)
|
Operating System: |
MacOS X →
Unknown/Multiple
|
Related Tickets: |
→ #9968
|
Resolution: |
→ duplicate
|
Status: |
new →
closed
|
Keywords: |
deriving added; DeriveAnyClass removed
|
Reproducable with HEAD (ghc-7.11.20151002).