https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88973
--- Comment #8 from Martin Sebor <msebor at gcc dot gnu.org> --- The Asan warning is much clearer because it's based on actually observed values. This instance of the -Wrestrict warning is based on a heuristic: "we think the copy may overlap because it is within the same object and we can't prove that the offsets and the size assure it doesn't happen." There may be a way to reword the warning to make things a little bit clearer but I don't think we can match the Asan form. When the offsets and the size are completely unbounded we could just avoid printing them altogether. That would make it: 'strcpy' accessing the same array may overlap [-Werror=restrict] When the size is known it would give us: 'strcpy' accessing N bytes of the same array may overlap [-Werror=restrict] and when the offsets are known but the size isn't: 'strcpy' accessing the same array at offsets [O1, O2] and [O3, O4] may overlap [-Werror=restrict] and so on. There are many forms of the -Wrestrict warning already: singular size (1 byte) vs plural size (bytes) vs closed range (between X and Y bytes) vs open range (X or more bytes), constant offsets vs closed ranges ([X, Y]), definitely overlaps vs may overlap, and others, and because of internationalization most have to be hardcoded and can't be easily parameterized, so adding a new form into the mix isn't completely straightforward.
