https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84596
--- Comment #6 from Vegard Nossum <vegard.nossum at gmail dot com> --- I see a similar ICE on r258221 using this test case: template<int x> struct a { constexpr int b() { int c; static_assert(c %= 1); } }; Output: $ xgcc -x c++ -S - <stdin>: In member function 'constexpr int a<x>::b()': <stdin>:5:21: error: non-constant condition for static assertion <stdin>:5:21: internal compiler error: unexpected expression '(bool)c %=1' of kind implicit_conv_expr 0xa3cfab cxx_eval_constant_expression /home/vegard/git/gcc/gcc/cp/constexpr.c:4770 0xa4de8a cxx_eval_outermost_constant_expr /home/vegard/git/gcc/gcc/cp/constexpr.c:4830 0x12a6a7d finish_static_assert(tree_node*, tree_node*, unsigned int, bool) /home/vegard/git/gcc/gcc/cp/semantics.c:8678 0xed0a31 cp_parser_static_assert /home/vegard/git/gcc/gcc/cp/parser.c:13947 0xfb0b11 cp_parser_block_declaration /home/vegard/git/gcc/gcc/cp/parser.c:12877 0xfb2094 cp_parser_declaration_statement /home/vegard/git/gcc/gcc/cp/parser.c:12474 0xefef9b cp_parser_statement /home/vegard/git/gcc/gcc/cp/parser.c:10923 0xf02a5b cp_parser_statement_seq_opt /home/vegard/git/gcc/gcc/cp/parser.c:11272 0xf034fa cp_parser_compound_statement /home/vegard/git/gcc/gcc/cp/parser.c:11226 0xf96a6b cp_parser_function_body /home/vegard/git/gcc/gcc/cp/parser.c:21776 0xf96a6b cp_parser_ctor_initializer_opt_and_function_body /home/vegard/git/gcc/gcc/cp/parser.c:21811 0xf9fc75 cp_parser_function_definition_after_declarator /home/vegard/git/gcc/gcc/cp/parser.c:26816 0xfa1f3c cp_parser_late_parsing_for_member /home/vegard/git/gcc/gcc/cp/parser.c:27697 0xf1c0e5 cp_parser_class_specifier_1 /home/vegard/git/gcc/gcc/cp/parser.c:22740 0xf2763b cp_parser_class_specifier /home/vegard/git/gcc/gcc/cp/parser.c:22766 0xf2763b cp_parser_type_specifier /home/vegard/git/gcc/gcc/cp/parser.c:16772 0xf8c7ba cp_parser_decl_specifier_seq /home/vegard/git/gcc/gcc/cp/parser.c:13627 0xfa6ddf cp_parser_single_declaration /home/vegard/git/gcc/gcc/cp/parser.c:27185 0xfc9658 cp_parser_template_declaration_after_parameters /home/vegard/git/gcc/gcc/cp/parser.c:26874 0xfc7c5b cp_parser_explicit_template_declaration /home/vegard/git/gcc/gcc/cp/parser.c:27112