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compiler/simplify_proc.m:
    For each constraint with different typeclass_infos in different branches,
    report what lines of code those typeclass_infos came from.
    (This can be a bit confusing if there is only one line, e.g. when
    a switch arm is automatically duplicated by the compiler, but it may
    still be helpful.)

    Improve the wording of the diagnostic.

compiler/polymorphism_type_class_info.m:
    Add contexts to the goal_infos of the goals that construct
    typeclass_infos, to make the above possible.

tests/invalid/tci_liveness_abort.err_exp:
    Expect the updated info and wording.

compiler/hlds_error_util.m:
    Delete all module qualifications from inst names in procedure
    argument modes, since they are just clutter.

tests/warnings/unused_args_some_modes.err_exp:
    Stop expecting module qualified inst names in procedure argument modes.

library/multi_map.m:
    Add the to_sorted_assoc_list operation in both predicate and
    function forms, for use by new code in simplify_proc.m.

NEWS.md:
    Announce the new predicate and function.