testsuite/tests/typecheck/should_fail/tcfail213.stderr


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tcfail213.hs:8:1:
    Illegal constraint `F a' in a superclass/instance context
      (Use -XUndecidableInstances to permit this)
    In the context: (F a)
    While checking the super-classes of class `C'
    In the class declaration for `C'