Skip to content

Make NoExt uninhabited

Currently HsExtension.NoExt is a unit type:

data NoExt = NoExt

However, it is always(?) used to fill extension constructors which generally aren't meaningful. This is awkward as you then have cases like !1265 (comment 209231) where GHC implementation is forced to deal with a constructor that should never actually occur.

It seems like NoExt should rather be unhabited:

data NoExt

Why isn't this the case?

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information