https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100248
--- Comment #1 from 康桓瑋 <hewillk at gmail dot com> ---
Reduced to no header:
struct S {};
bool operator==(S&&, S&&) = default;
<source>:2:29: internal compiler error: Segmentation fault
2 | bool operator==(S&&, S&&) = default;
| ^~~~~~~
0x1cff019 internal_error(char const*, ...)
???:0
0x1366c00 strip_array_types(tree_node*)
???:0
0x9c9778 cp_type_quals(tree_node const*)
???:0
0x9ba4c3 cp_build_qualified_type_real(tree_node*, int, int)
???:0
0x82f194 defaultable_fn_check(tree_node*)
???:0
0x7b2cc8 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
???:0
0x8e1f6d c_parse_file()
???:0
0xa621b2 c_common_parse_file()
???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
