[Bug c++/99831] New: ICE: in reshape_init, at cp/decl.c:6720

[hewillk at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99831

            Bug ID: 99831
           Summary: ICE: in reshape_init, at cp/decl.c:6720
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

This is a complicated one since I don't know how to reduce it.

https://godbolt.org/z/rqTGxMWef

#include <algorithm>

template <int N>
struct StringLiteral {
  constexpr StringLiteral(const char (&str)[N]) {
    std::ranges::copy_n(str, N, value);
  }
  char value[N];
};

template <StringLiteral>
struct string{
  constexpr bool operator==(const string&) const noexcept = default;
};

template <StringLiteral L1, StringLiteral L2>
constexpr auto operator+(string<L1>, string<L2>) {
  constexpr auto L3 = []{
    constexpr auto size1 = sizeof(L1.value);
    constexpr auto size2 = sizeof(L2.value);
    char value[size1 + size2 - 1] = {};
    std::ranges::sort(value);
    std::ranges::copy_n(L1.value, size1, value);
    std::ranges::copy_n(L2.value, size2, value + size1 - 1);
    return StringLiteral{value};
  }();
  return string<L3>{};
}

static_assert(
  string<"hello, world">{} ==
  string<"hello">{} + string<", world">{}
);

static_assert(
  string<"a rose is a rose is a rose">{} ==
  string<"a rose">{} + string<" is ">{} + 
  string<"a rose">{} + string<" is ">{} + 
  string<"a rose">{}
);

<source>:36:40: internal compiler error: in reshape_init, at cp/decl.c:6720
   36 |   string<"a rose is a rose is a rose">{} ==
      |                                        ^
0x1cfb6a9 internal_error(char const*, ...)
        ???:0
0x6ba871 fancy_abort(char const*, int, char const*)
        ???:0
0x7810b6 reshape_init(tree_node*, tree_node*, int)
        ???:0
0x97e050 finish_compound_literal(tree_node*, tree_node*, int, fcl_t)
        ???:0
0x8e12ad c_parse_file()
        ???:0
0xa600a2 c_common_parse_file()
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.