• Simon Marlow's avatar
    Fix bug when the combined package DB has duplicate package IDs · 1c5fb336
    Simon Marlow authored
    Someone on IRC reported that they were encountering a strange missing
    module error from GHC, and it turned out that they had mtl-
    installed in both the global and local DB, with the same
    InstalledPackageId.  The two packages should be interchangeable, but
    we were forgetting to eliminate duplicates in part of the
    package-processing phase in GHC.
    Really I should switch this code over to use the new PackageIndex data
    type in Cabal, which ought to make things simpler.
Packages.lhs 36 KB