Error found:
in module Main
at tests/purs/failing/DuplicateTypeVars.purs:6:1 - 6:17 (line 6, column 1 - line 6, column 17)

  Type argument a appears more than once.

in type synonym Foo

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