Data type with phantoms using TypeInType isn't coercible
I'm *pretty* sure this is a problem with TypeInType in particular. I'd expect the following to compile:
{-# LANGUAGE GADTs, TypeInType, TypeApplications #-}
module Bug where
import Prelude
import Data.Coerce
import Data.Kind
data Foo a = Foo
data Bar (a :: Type) (b :: Foo a) where
Bar :: Bar a 'Foo
x = coerce @(Bar Int 'Foo) @(Bar Bool 'Foo)But it doesn't
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.4.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
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| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |