Panic: promoteType with higher-rank datatype
The following code causes the panic in HEAD:
{-# LANGUAGE DataKinds, RankNTypes, TypeFamilies #-}
data HigherRank = HR (forall a. a -> a)
type family F (x :: HigherRank)
type instance F (HR x) = Bool
Here is the panic text:
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 7.7.20130329 for x86_64-apple-darwin):
promoteType
This panic does not happen with GHC 7.6.1.
Trac metadata
Trac field | Value |
---|---|
Version | 7.7 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |