Incorrect warning about redundant constraints
The following program results in an incorrect warning about a redundant constraint:
{-# LANGUAGE TypeFamilies #-}
type family SomeFun a
f :: (SomeFun i ~ [a], Read a) => proxy i -> a
f _ = read "HELLO"
This is the warning:
Redundant constraint: SomeFun i ~ [a]
In the type signature for:
f :: (SomeFun i ~ [a], Read a) => proxy i -> a
I tried it on GHC version 7.11.20151029
Trac metadata
Trac field | Value |
---|---|
Version | 7.11 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |