existential types produce invalid TS

[John Jackson]

@gentype
type rec t = Any('a): t

output:

export type t = { tag: "Any"; value: a };

Cannot find name 'a'.
Property 'value' of exported interface has or is using private name 'a'.

[Cristiano Calcagno]

There's no support for exporting GADTs at the moment. It's not clear what TS type they would map to.

[John Jackson]

Would it be possible for gentype to output type names like any or unknown for cases that aren’t supported? Or could it print a warning/error so the user can work around it? Either way, silently outputting invalid code seems unideal.

[Cristiano Calcagno]

Indeed, it makes sense to give a warning in this case.
Doing it here: #504
Also, exporting it as opaque in that case, so it's a black box from TS.