• Simon Peyton Jones's avatar
    Minimise provided dictionaries in pattern synonyms · 2c2f3cea
    Simon Peyton Jones authored
    Trac #14394 showed that it's possible to get redundant
    constraints in the inferred provided constraints of a pattern
    synonym.  This patch removes the redundancy with mkMinimalBySCs.
    
    To do this I had to generalise the type of mkMinimalBySCs slightly.
    And, to reduce confusing reversal, I made it stable: it now returns
    its result in the same order as its input.  That led to a raft of
    error message wibbles, mostly for the better.
    2c2f3cea
ExtraConstraints3.stderr 9.46 KB