Error found:
in module Main
at tests/purs/failing/QuantifiedKind.purs:6:22 - 6:23 (line 6, column 22 - line 6, column 23)

  Type variable k is undefined.

while inferring the kind of k
while checking that type k
  has kind Type
while inferring the kind of forall (a :: k) k. Proxy a
in value declaration test

See https://github.com/purescript/documentation/blob/master/errors/UndefinedTypeVariable.md for more information,
or to contribute content related to this error.