Error found: in module Main at tests/purs/failing/CoercibleRoleMismatch4.purs:4:1 - 4:19 (line 4, column 1 - line 4, column 19) Role mismatch for the type parameter a: The annotation says representational but the role nominal is required. in role declaration for F in data binding group F, G See https://github.com/purescript/documentation/blob/master/errors/RoleMismatch.md for more information, or to contribute content related to this error.