• simonpj@microsoft.com's avatar
    Preserve type variable names during type inference · a9da016a
    simonpj@microsoft.com authored
    During unification we attempt to preserve the print-names of type variables,
    so that type error messages tend to mention type variables using the 
    programmer's vocabulary.  
    This had bit-rotted a bit when I added impredicative polymorphism; especially
    when unBoxing a boxy type variable we should not gratuitously lose its name.
TcUnify.lhs 61.3 KB