
IIUC Jan is working on a ghc branch, not a plugin. But perhaps this ticket
will point in the right direction anyway? HTH.
https://gitlab.haskell.org/ghc/ghc/issues/16639
On Mon, Sep 30, 2019, 01:44 Richard Eisenberg
Hi Jan,
The ambiguity check has a simple description. To test if a type `ty` is ambiguous, do this:
``` x :: ty x = x ```
Iff that type-checks, the type is unambiguous. That's it!
The check does not manufacture a binding `x`, but the implementation runs through the type-checking process for a binding just like the one I've written here.
In your case, I have two hypotheses: 1. Presumably, you have a solver plugin at work. That may explain the difference in behavior between the two cases. 2. There may be kind variables at work, and these may end up ambiguous. It's definitely worth trying with -fprint-explicit-kinds.
I hope this helps! Richard _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs