Type synonym for Type family + DataKinds won't recompile due to internal error
I have following program:
{-# LANGUAGE DataKinds, TypeFamilies, GADTs #-}
module Main where
data U = Unit
data SU (a :: U) where
SInt :: SU Unit
type family I (a :: U) :: U
type instance I Unit = Unit
type SUI a = SU (I a)
main :: IO ()
main = return ()This program compiles successfully, but won't recompile due to an internal error.
$ ghc WontCompile.hs
[1 of 1] Compiling Main ( WontCompile.hs, WontCompile.o )
Linking WontCompile ...
$ ghc WontCompile.hs -fforce-recomp
[1 of 1] Compiling Main ( WontCompile.hs, WontCompile.o )
WontCompile.hs:12:18:
GHC internal error: `I' is not in scope during type checking, but it passed the renamer
tcl_env of environment: [(a9O, AThing k_a9X)]
In the type `SU (I a)'
In the type synonym declaration for `SUI'Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.4.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |