Panic with incorrect pattern synonym signature
{-# LANGUAGE PatternSynonyms #-}
module Foo () where
data A a = A a
pattern Q :: () => (A ~ f) => a -> f a
pattern Q a = A a
error with HEAD
poly-export2.hs:7:9: error:ghc-stage2: panic! (the 'impossible' happened)
(GHC version 7.11.20151030 for x86_64-apple-darwin):
No skolem info: f_amp[sk]
Trac metadata
Trac field | Value |
---|---|
Version | 7.11 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | high |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |