https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103712
Bug ID: 103712 Summary: variable is not a constant expression because it is used in its own initializer Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: barry.revzin at gmail dot com Target Milestone: --- Reduced from StackOverflow (https://stackoverflow.com/q/70342678/2069064): struct selfref { selfref* next = nullptr; }; struct exec { selfref mem = selfref{}; constexpr exec() { mem.next = &mem; } }; constexpr exec do_thing() { return exec{}; } constexpr exec ret = do_thing(); constexpr selfref* ptr = ret.mem.next; I think this should compile - ret.mem.next points to ret.mem, which is okay since ret has static storage duration. And then ptr should be pointing to something that has static storage duration, which is a permitted result. gcc currently rejects with: <source>:19:26: error: the value of 'ret' is not usable in a constant expression 19 | constexpr selfref* ptr = ret.mem.next; | ^~~ <source>:18:16: note: 'ret' used in its own initializer 18 | constexpr exec ret = do_thing(); | ^~~ This seems vaguely related to CWG 2278, but do_thing() isn't doing copy elision, so I think this should work.