Since IUSE_IMPLICIT is awfully stupid in EAPI=4, I think it would be really useful if repoman warned when someone tries to use '(-)' or '(+)' USE default on package with such a flag. The IUSE_IMPLICIT rules make the flags implicitly available in the ebuild even if they're not declared by it. Therefore, USE defaults are meaningless and mostly result in broken ebuilds/eclasses being committed to the tree. By 'broken', I mean 'broken when used with Paludis'.
To clarify, IUSE_IMPLICIT in this context means USE_EXPAND flags in EAPI 4 and earlier, right?
(In reply to comment #1) > To clarify, IUSE_IMPLICIT in this context means USE_EXPAND flags in EAPI 4 > and earlier, right? In my particular mistake, yes. But I think the check could be generalized to anything PMS puts in IUSE_IMPLICIT since the USE defaults are meaningless there as well.
Okay, that makes sense. For EAPI 5, it's not just IUSE_IMPLICIT, but also other profile variables like USE_EXPAND_IMPLICIT and USE_EXPAND_VALUES_*.
repoman support has been removed per bug 835013. Please file a new bug (or, I suppose, reopen this one) if you feel this check is still applicable to pkgcheck and doesn't already exist.