https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107574
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-12 branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:b7b50918fe52206e188c8c60c60e0d6a516e8572 commit r12-9216-gb7b50918fe52206e188c8c60c60e0d6a516e8572 Author: Marek Polacek <pola...@redhat.com> Date: Thu Feb 2 18:15:37 2023 -0500 c++: can't eval PTRMEM_CST in incomplete class [PR107574] Here we're attempting to evaluate a PTRMEM_CST in a class that hasn't been completed yet, but that doesn't work: /* We can't lower this until the class is complete. */ if (!COMPLETE_TYPE_P (DECL_CONTEXT (member))) return cst; and then this unlowered PTRMEM_CST is used as EXPR in tree op1 = build_nop (ptrdiff_type_node, expr); and we crash in a subsequent cp_fold_convert which gets type=ptrdiff_type_node, expr=PTRMEM_CST and does else if (TREE_CODE (expr) == PTRMEM_CST && same_type_p (TYPE_PTRMEM_CLASS_TYPE (type), PTRMEM_CST_CLASS (expr))) where TYPE_PTRMEM_CLASS_TYPE (type) is going to crash since the type is ptrdiff_type_node. We could just add a TYPE_PTRMEM_P check before accessing TYPE_PTRMEM_CLASS_TYPE but I think it's nicer to explain why we couldn't evaluate the expression. PR c++/107574 gcc/cp/ChangeLog: * constexpr.cc (cxx_eval_constant_expression): Emit an error when a PTRMEM_CST cannot be evaluated. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/ptrmem-cst1.C: New test. (cherry picked from commit de81e06273c613d7e06cbe2c8d9e72826c638056)
