Panic with piResultTys1
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE ScopedTypeVariables #-}
twacePowDec :: t m' r -> t m r
twacePowDec = undefined
data Bench a
bench :: (a -> b) -> a -> Bench params
bench f = undefined
bench_twacePow :: forall t m m' r . _ => t m' r -> Bench '(t,m,m',r)
bench_twacePow = bench (twacePowDec :: t m' r -> t m r)
produces (in GHCi):
GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help
[1 of 1] Compiling Main ( Bug.hs, interpreted )
Bug.hs:13:58: error:
• Expected a type, but
‘'(t, m, m', r)’ has kind
‘(k1 -> k2 -> *, k0, k1, k2)’
• In the first argument of ‘Bench’, namely ‘'(t, m, m', r)’
In the type ‘t m' r -> Bench '(t, m, m', r)’
Bug.hs:14:52: error:
• Expected kind ‘k1’, but ‘m’ has kind ‘k0’
• In the first argument of ‘t’, namely ‘m’
In an expression type signature: t m' r -> t m r
In the first argument of ‘bench’, namely
‘(twacePowDec :: t m' r -> t m r)’
• Relevant bindings includeghc: panic! (the 'impossible' happened)
(GHC version 8.0.1 for x86_64-unknown-linux):
piResultTys1
k_a18K[tau:3]
[m'_a17U[sk], r_a17V[sk]]
The intent was to use this code with -XPartialTypeSignatures
, but the bug occurs with or without that extension.
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |