IIRC, when two packages A and B depend on the same package C in two different USE variants of flag F, portage will emit an error of the kind C[F] required by A conflicts with C[-F] required b B I think a similar information should be displayed when a package A requires C[F] but current USE flags disagree. Instead, emerge currently displays a message of the sort C conflicts with C[F,G,H] required by A which doesn't readily reveal the conflict and someone with no prior knowledge can't make sense of the error. Instead, it should indicate where the actual conflict occurs (in this case, in the USE flag) like C[-F,G,H] conflicts with C[F,G,H] required by A or even just C[-F] conflicts with C[F] required by A
As an example, the problem that motivated this bug from IRC: > x11-libs/libXdmcp:0 > > (x11-libs/libXdmcp-1.1.2-r1:0/0::gentoo, ebuild scheduled for merge) conflicts with > >=x11-libs/libXdmcp-1.1.1-r1[abi_x86_32(-),abi_x86_64(-)] required by (x11-libs/libxcb-1.12-r2:0/1.12::gentoo, installed)
It was pointed out to me, that the error message must necessarily state C conflicts with C[F(-)] if, indeed, C does not have any USE flag F in it's current version, where latter is thus assumed unset as by the (-). I'd therefore say that if such is the case, the error message is correct. If, however, C does have a USE flag F (as it is the case in the above example), it (and thus the precise conflict) should be mentioned.
