GHC 7.10.1 panic due to PartialTypeSignatures, TypeFamilies, and local bindings
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE TypeFamilies #-}
module Bad
where
foo f = g
where g r = x
where x :: _
x = r
When compiled, it produces the following output:
[1 of 1] Compiling Bad ( src/Bad.hs, src/Bad.o )
src/Bad.hs:8:22: Warning:
Found hole ‘_’ with type: w_1
Where: ‘w_1’ is a rigid type variable bound by
the inferred type of g :: w_1 -> w_1 at src/Bad.hs:7:9
Relevant bindings include
r :: w_1 (bound at src/Bad.hs:7:11)
g :: w_1 -> w_1 (bound at src/Bad.hs:7:9)
f :: t (bound at src/Bad.hs:6:5)
foo :: t -> w_ -> w_ (bound at src/Bad.hs:6:1)
In the type signature for ‘x’: _
In an equation for ‘g’:
g r
= x
where
x :: _
x = r
In an equation for ‘foo’:
foo f
= g
where
g r
= x
where
x :: _
x = r
ghc: panic! (the 'impossible' happened)
(GHC version 7.10.1 for x86_64-unknown-linux):
StgCmmEnv: variable not found
x_alC
local binds for:
f_sv5
r_sv6
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
Trac metadata
Trac field | Value |
---|---|
Version | 7.10.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | high |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |