Error found:
in module Main
at tests/purs/failing/CoercibleRoleMismatch3.purs:10:1 - 10:29 (line 10, column 1 - line 10, column 29)

  Role mismatch for the type parameter a:

    The annotation says representational but the role nominal is required.


in role declaration for U

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