https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123680
Bug ID: 123680
Summary: [16 Regression] ICE in type_has_nontrivial_copy_init
(at cp/tree.cc) during CTAD with lambda-NTTP default
argument
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jirehguo at tju dot edu.cn
Target Milestone: ---
Compiler Explorer: https://godbolt.org/z/jWjqeWo6G
The following c++ code crash gcc trunk with -std=c++20 flag.
But gcc 12,13,14,15 with checking is fine.
Code:
```cpp
template < auto B =
[] {
struct E {
E();
};
E();
}>
struct A;
A x;
```
Stack dump:
```
<source>: In substitution of 'template<auto B> A() -> A<B> [with auto B =
<missing>]':
required from here
<source>:9:3:
9 | A x;
| ^
<source>:6:17: internal compiler error: in type_has_nontrivial_copy_init, at
cp/tree.cc:4842
6 | E();
| ^~~
0x2950a78 diagnostics::context::diagnostic_impl(rich_location*,
diagnostics::metadata const*, diagnostics::option_id, char const*,
__va_list_tag (*) [1], diagnostics::kind)
???:0
0x294583b internal_error(char const*, ...)
???:0
0xb1ec34 fancy_abort(char const*, int, char const*)
???:0
0xe41a7d build_target_expr_with_type(tree_node*, tree_node*, int)
???:0
0xe6924d build_functional_cast(unsigned long, tree_node*, tree_node*, int)
???:0
0xd8f0de tsubst_lambda_expr(tree_node*, tree_node*, int, tree_node*)
???:0
0xda0531 tsubst_template_arg(tree_node*, tree_node*, int, tree_node*)
???:0
0xdca851 fn_type_unification(tree_node*, tree_node*, tree_node*, tree_node*
const*, unsigned int, tree_node*, unification_kind_t, int, conversion**, bool,
bool)
???:0
0xb542c9 perform_dguide_overload_resolution(tree_node*, vec<tree_node*, va_gc,
vl_embed> const*, int)
???:0
0xd8ce97 do_auto_deduction(tree_node*, tree_node*, tree_node*, int,
auto_deduction_context, tree_node*, int, tree_node*)
???:0
0xc26d61 cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int,
cp_decomp*)
???:0
0xd64c03 c_parse_file()
???:0
0xeeed49 c_common_parse_file()
???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1
```
