https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117615
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Simon Martin <simar...@gcc.gnu.org>: https://gcc.gnu.org/g:322faea202947561ee8c03edf5ab0ccf649587e1 commit r13-9230-g322faea202947561ee8c03edf5ab0ccf649587e1 Author: Simon Martin <si...@nasilyan.com> Date: Tue Dec 3 14:30:43 2024 +0100 c++: Don't reject pointer to virtual method during constant evaluation [PR117615] We currently reject the following valid code: === cut here === struct Base { virtual void doit (int v) const {} }; struct Derived : Base { void doit (int v) const {} }; using fn_t = void (Base::*)(int) const; struct Helper { fn_t mFn; constexpr Helper (auto && fn) : mFn(static_cast<fn_t>(fn)) {} }; void foo () { constexpr Helper h (&Derived::doit); } === cut here === The problem is that since r6-4014-gdcdbc004d531b4, &Derived::doit is represented with an expression with type pointer to method and using an INTEGER_CST (here 1), and that cxx_eval_constant_expression rejects any such expression with a non-null INTEGER_CST. This patch uses the same strategy as r12-4491-gf45610a45236e9 (fix for PR c++/102786), and simply lets such expressions go through. PR c++/117615 gcc/cp/ChangeLog: * constexpr.cc (cxx_eval_constant_expression): Don't reject INTEGER_CSTs with type POINTER_TYPE to METHOD_TYPE. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/constexpr-virtual22.C: New test. (cherry picked from commit 72a2380a306a1c3883cb7e4f99253522bc265af0)
