• thomie's avatar
    Testsuite: add regression test for missing class constraint · 029367e5
    thomie authored
    The following program is accepted by ghc-7.0 to ghc-7.10, but rejected
    by ghc-6.12.3 and HEAD (and rightfully so):
    
        class Class1 a
        class Class1 a => Class2 a
        class Class2 a => Class3 a
        instance Class3 a => Class2 a
    
    The last line is missing a `Class1 a` constraint. Add a regression test
    for this (typechecker/should_fail/tcfail223).
    
    Add similar missing class constraints to T7126 and T5751. I verified
    that the these changes don't interfer with the intention of the tests
    (they still result in a loop with ghc-7.4.1).
    
    Reviewers: austin, simonpj, bgamari
    
    Reviewed By: bgamari
    
    Subscribers: rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D1078
    029367e5
tcfail223.stderr 352 Bytes