https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124978
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-16 branch has been updated by Patrick Palka <[email protected]>: https://gcc.gnu.org/g:a5d39331b959364c25908669194377bac19316b8 commit r16-9144-ga5d39331b959364c25908669194377bac19316b8 Author: Patrick Palka <[email protected]> Date: Mon Apr 27 17:56:18 2026 -0400 c++: fix decltype(id) for pointer-to-data-member access expr [PR124978] Here after substitution into decltype(X), X is the expanded but not constant-evaluated pointer-to-data-member access expression *((const int *) *cw<Divide{42}>::value + (sizetype) *cw<&Divide::value>::value) and finish_decltype_type wrongly strips the outermost INDIRECT_REF under the assumption that it's an implicit dereference of a reference, but here it's an explicit pointer dereference. This causes the decltype to yield const int* instead of the expected int. This patch fixes this particular bug by checking REFERENCE_REF_P instead of INDIRECT_REF_P which additionally verifies the dereferenced thing actually has reference type. The decltype now yields the correct type modulo an unnecessary const due to the separate bug PR115314. PR c++/124978 PR c++/115314 gcc/cp/ChangeLog: * semantics.cc (finish_decltype_type): Check REFERENCE_REF_P instead of INDIRECT_REF_P before stripping implicit dereferences. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/nontype-class74.C: New test. Reviewed-by: Jason Merrill <[email protected]> (cherry picked from commit c607c686100689e3e68487cd8097c2fbd3904168)
