9.6.2: haddock panic exporting bare `type data` constructor
Summary
Running Haddock on the below module results in:
panic! (the 'impossible' happened)
GHC version 9.6.2:
tyConStupidTheta
FooCon
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/GHC/Utils/Panic.hs:189:37 in ghc:GHC.Utils.Panic
pprPanic, called at compiler/GHC/Core/TyCon.hs:2649:17 in ghc:GHC.Core.TyCon
Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug
Steps to reproduce
{-# LANGUAGE TypeData #-}
module Bug (FooCon) where -- to avoid panic, export `Foo(FooCon)` instead
type data Foo = FooCon
Expected behavior
Not a panic. Either Haddock and GHC should both reject exporting FooCon
without being wrapped in Foo()
, or Haddock should handle this successfully.
Environment
- GHC version used: 9.6.2
Optional:
- Operating System: Linux (NixOS)
- System Architecture: x86_64