https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85689
W E Brown <webrown.cpp at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |webrown.cpp at gmail dot com --- Comment #1 from W E Brown <webrown.cpp at gmail dot com> --- I believe the test program demonstrates that g++ is behaving correctly in processing static_assert in the context of a constexpr if. The demonstrated behavior is part of the design of the constexpr if facility as proposed for and adopted into C++17. Please see wg21.link/p0292, which in section "Not proposed" exhibits an example very similar to the submitted test program, pronouncing it "ill-formed". I respectfully recommend this issue be closed as INVALID, as it seems to be based on a misunderstanding.