• Ryan Scott's avatar
    Suppress redundant givens during error reporting · c552feea
    Ryan Scott authored
    When GHC reports that it cannot solve a constraint in error
    messages, it often reports what given constraints it has in scope.
    Unfortunately, sometimes redundant constraints (like `* ~ *`, from
    #15361) can sneak in. The fix is simple: blast away these redundant
    constraints using `mkMinimalBySCs`.
    Test Plan: make test TEST=T15361
    Reviewers: simonpj, bgamari
    Subscribers: rwbarton, thomie, carter
    GHC Trac Issues: #15361
    Differential Revision: https://phabricator.haskell.org/D5002
T15361.stderr 1.39 KB