https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126840
Bug ID: 126840
Summary: ICE on invalid alignas() declaration with empty
attribute argument
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: s.kimura.h41104 at gmail dot com
Target Milestone: ---
Compiler Explorer: https://godbolt.org/z/WhT65o86v
Reproducer:
```
int foo() {
alignas() {}
return 0;
}
```
Backtrace:
<source>:2:11: error: expected primary-expression before ')' token
2 | alignas() {}
| ^
<source>:3:10: internal compiler error: tree check: expected tree_list, have
error_mark in get_attribute_name, at attribs.cc:1062
3 | return 0;
| ^
0x2bae358 diagnostics::context::diagnostic_impl(rich_location*,
diagnostics::metadata const*, diagnostics::option_id, char const*,
__va_list_tag (*) [1], diagnostics::kind)
???:0
0x2ba2f9b internal_error(char const*, ...)
???:0
0xa3bc74 tree_check_failed(tree_node const*, char const*, int, char const*,
...)
???:0
0xd98493 c_parse_file()
???:0
0xf2b969 c_common_parse_file()
???:0
This ICE goes back to gcc-15:
https://godbolt.org/z/nEKnx5TPc
