https://gcc.gnu.org/g:6d87c68f9904bab176c26359cdbb4a9001247cff
commit r16-9275-g6d87c68f9904bab176c26359cdbb4a9001247cff Author: Marek Polacek <[email protected]> Date: Mon Jul 13 17:47:09 2026 -0400 c++: ICE with requires and -Wsequence-point [PR126066] We trip on the assert in lvalue_kind/MODOP_EXPR whose comment says that we expect to see MODOP_EXPRs only during template processing. In this test we get there with processing_template_decl==0. The MODOP_EXPR is created in: /* Parse the requirement body. */ ++processing_template_decl; reqs = cp_parser_requirement_body (parser); --processing_template_decl; but we're not in a template when calling maybe_convert_cond which calls verify_sequence_points which ends up calling lvalue_p on the MODOP_EXPR. verify_sequence_points is walking the unevaluated operand of a requires because verify_tree assumes that all unknown expressions are evaluated, and REQUIRES_EXPR looks like a normal expression (tcc_expression). The trunk patch changed REQUIRES_EXPR to tcc_exceptional. But in 16, we can just dial the assert down to _checking. PR c++/126066 gcc/cp/ChangeLog: * tree.cc (lvalue_kind) <case MODOP_EXPR>: Use gcc_checking_assert instead of gcc_assert. Reviewed-by: Jason Merrill <[email protected]> Diff: --- gcc/cp/tree.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc index 2bcbfa847079..1da3e7d6fc2a 100644 --- a/gcc/cp/tree.cc +++ b/gcc/cp/tree.cc @@ -280,7 +280,7 @@ lvalue_kind (const_tree ref) case MODOP_EXPR: /* We expect to see unlowered MODOP_EXPRs only during template processing. */ - gcc_assert (processing_template_decl); + gcc_checking_assert (processing_template_decl); if (CLASS_TYPE_P (TREE_TYPE (TREE_OPERAND (ref, 0)))) goto default_; else
