https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116567
Bug ID: 116567
Summary: Display "Compiler internal error" when using default
non-type template parameter.
Product: gcc
Version: 14.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: polarlinda6 at 163 dot com
Target Milestone: ---
```cpp
template<auto, auto = [] {}>
bool flag = true;
template<typename>
struct core {
template<typename>
auto func() -> bool {
return flag<0>;
}
};
auto main() -> int {
core<int> _;
[[maybe_unused]] bool flag = _.func<int>();
}
```
error message:
<source>: In instantiation of 'bool core< <template-parameter-1-1> >::func()
[with <template-parameter-2-1> = int; <template-parameter-1-1> = int]':
<source>:15:43: required from here
15 | [[maybe_unused]] bool flag = _.func<int>();
| ~~~~~~~~~~~^~
<source>:2:23: internal compiler error: in tsubst, at cp/pt.cc:16442
2 | template<auto, auto = [] {}>
| ^~~~~
0x2031cbc internal_error(char const*, ...)
???:0
0x77895f fancy_abort(char const*, int, char const*)
???:0
0x939840 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0x944481 tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*)
???:0
0x93cea7 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
???:0
0x93247f instantiate_decl(tree_node*, bool, bool)
???:0
0x94df63 instantiate_pending_templates(int)
???:0
0x8355a8 c_parse_final_cleanups()
???:0
0xa0d1e8 c_common_parse_file()
???:0
Additional Information:
Version: x86-64 gcc 14.2.1
command-line parameter: -std=c++20
Link: https://godbolt.org/z/9sTTcT4Mo
PS: The code compiles successfully on msvc and clang.
