[Bug c++/67159] New: [c++concepts] Segfault while diagnosing constraint violation

[Casey at Carter dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67159

            Bug ID: 67159
           Summary: [c++concepts] Segfault while diagnosing constraint
                    violation
           Product: gcc
           Version: c++-concepts
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: Casey at Carter dot net
  Target Milestone: ---

Created attachment 36149
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36149&action=edit
Preprocessed test case

r226725 crashes while diagnosing a constraint violation in this correct program
(pre-processed test case attached):

#include <stl2/detail/iterator/concepts.hpp>

template <class T>
concept bool R = requires (T& t) {
  { t.begin() } -> stl2::Iterator;
  { t.end() } -> stl2::Sentinel<decltype(t.begin())>;
};

struct foo {
  int* begin();
  int* end();
};

R{T}
constexpr bool f() { return true; }

static_assert(f<foo>());

resulting in:

~/concept-gcc-r226725/bin/g++ -std=gnu++1z foo.i -c
foo.cpp:17:22: error: cannot call function ‘constexpr bool f() [with T = foo]’
 static_assert(f<foo>());
                      ^
foo.cpp:15:16: note:   constraints not satisfied
 constexpr bool f() { return true; }
                ^
‘
Segmentation fault
 static_assert(f<foo>());
                      ^
0xc9055f crash_signal
        ../../gcc/toplev.c:352
0xf0f506 contains_struct_check(tree_node const*, tree_node_structure_enum, char
const*, int, char const*)
        ../../gcc/tree.h:3227
0xf0f506 int_cst_value(tree_node const*)
        ../../gcc/tree.c:10982
0x6d03c4 get_non_default_template_args_count
        ../../gcc/cp/error.c:202
0x6da0b1 dump_template_argument_list
        ../../gcc/cp/error.c:211
0x6d52bd dump_decl
        ../../gcc/cp/error.c:1215
0x6dae15 expr_to_string
        ../../gcc/cp/error.c:2954
0x6dea54 cp_printer
        ../../gcc/cp/error.c:3530
0x13a309a pp_format(pretty_printer*, text_info*)
        ../../gcc/pretty-print.c:612
0x13a0573 diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*)
        ../../gcc/diagnostic.c:915
0x13a09d1 inform(unsigned int, char const*, ...)
        ../../gcc/diagnostic.c:1044
0x738a81 cp_build_function_call_vec(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
        ../../gcc/cp/typeck.c:3492
0x5f1e29 build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, bool, int)
        ../../gcc/cp/call.c:4090
0x77b850 finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
        ../../gcc/cp/semantics.c:2391
0x6fa019 cp_parser_postfix_expression
        ../../gcc/cp/parser.c:6419
0x6fe92a cp_parser_unary_expression
        ../../gcc/cp/parser.c:7486
0x6ff53f cp_parser_binary_expression
        ../../gcc/cp/parser.c:8223
0x6ffc9f cp_parser_assignment_expression
        ../../gcc/cp/parser.c:8481
0x700115 cp_parser_constant_expression
        ../../gcc/cp/parser.c:8727
0x702a94 cp_parser_static_assert
        ../../gcc/cp/parser.c:12296
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with preprocessed source if appropriate.
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