https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105996
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jason at gcc dot gnu.org --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The problem is that build_ptrmemfunc in 9587 if (TREE_CODE (pfn) != PTRMEM_CST) 9588 { 9589 if (same_type_p (to_type, pfn_type)) 9590 return pfn; 9591 else if (integer_zerop (n) && TREE_CODE (pfn) != CONSTRUCTOR) 9592 return build_reinterpret_cast (input_location, to_type, pfn, 9593 complain); 9594 } calls build_reintepret_cast from void (A::*)() typed pfn to void (B::*)() type, and when we then constant expression evaluate it, we reject it because reinterpret_cast is not a core constant expression as per https://eel.is/c++draft/expr.const#5.16 Now, is this reinterpret cast just some implementation detail under the hood in which we should somehow arrange for REINTERPRET_CAST_P bit not be set (or afterwards remove it)?