[Bug c++/114303] New: ICE with constexpr if and static_assert accessing captures across nested generic lambdas

["benbarsdell at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114303

            Bug ID: 114303
           Summary: ICE with constexpr if and static_assert accessing
                    captures across nested generic lambdas
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: benbarsdell at gmail dot com
  Target Milestone: ---

Similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105788 but the
backtrace is different.

https://godbolt.org/z/xMPeTo633

Repros with the following versions on Godbolt:
14.0.1 ICE (gcc trunk on Godbolt)
13.2: ICE
13.1: ICE
12.3: ICE
12.2: OK
12.1: OK
11.4: ICE
11.3: OK


#include <type_traits>

int main() {
    auto foo = [](auto level1) {
        return [&](auto ) {
            return [&](auto level3) {
                if constexpr (decltype(level3)::value) {
                    static_assert(decltype(level1)::value, "");
                }
                return 0;
            }(std::integral_constant<int, 1>());
        }(0);
    }(std::integral_constant<int, 1>());
}


<source>:8:17: internal compiler error: trying to capture 'level1' in
instantiation of generic lambda
    8 |                 if constexpr (decltype(level3)::value) {
      |                 ^~
0x265eabc internal_error(char const*, ...)
        ???:0
0xb86956 add_capture(tree_node*, tree_node*, tree_node*, bool, bool, unsigned
int*)
        ???:0
0xb869d9 add_default_capture(tree_node*, tree_node*, tree_node*)
        ???:0
0x16c682c walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*,
tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*))
        ???:0
0x16c68a9 walk_tree_1(tree_node**, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*,
tree_node* (*)(tree_node**, int*, tree_node* (*)(tree_node**, int*, void*),
void*, hash_set<tree_node*, false, default_hash_traits<tree_node*> >*))
        ???:0
0xc75f26 build_extra_args(tree_node*, tree_node*, int)
        ???:0
0xcab766 tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*)
        ???:0
0xc919b3 instantiate_decl(tree_node*, bool, bool)
        ???:0
0xb54725 maybe_instantiate_decl(tree_node*)
        ???:0
...