Error found:
in module Main
at tests/purs/failing/CoercibleRoleMismatch3.purs:8:1 - 8:23 (line 8, column 1 - line 8, column 23)

  Role mismatch for the type parameter a:

    The annotation says representational but the role nominal is required.


in role declaration for U
in type constructor U

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