https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103667
Bug ID: 103667
Summary: [12 Regression] Accepting invalid explicitly
specialized template with incorrectly ordered template
parameter lists
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: matthewjbarichello at gmail dot com
Target Milestone: ---
The following invalid code compiles without an error in GCC 12:
template<typename... Args>
struct A {
template<auto N>
struct B {};
};
template<>
template<typename... Args>
struct A<Args...>::B<sizeof...(Args)> {};
In versions before 12, compilation yields the following diagnostic:
<source>:9:22: error: template argument 'sizeof... (Args)' involves template
parameter(s)
9 | struct A<Args...>::B<sizeof...(Args)> {};
| ^~~~~~~~~~~~~~~
Adding the following code to the example causes a parser ICE:
int main() {
A<>::B<0> b{};
}
ICE trace:
<source>: In function 'int main()':
<source>:9:20: internal compiler error: in retrieve_specialization, at
cp/pt.c:1260
9 | struct A<Args...>::B<sizeof...(Args)> {};
| ^~~~~~~~~~~~~~~~~~
0x2100639 internal_error(char const*, ...)
???:0
0x7e96eb fancy_abort(char const*, int, char const*)
???:0
0xa5db37 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0xa942e9 most_specialized_partial_spec(tree_node*, int)
???:0
0xaa14f4 instantiate_class_template(tree_node*)
???:0
0x8bd4e7 start_decl_1(tree_node*, bool)
???:0
0x8e49bf start_decl(cp_declarator const*, cp_decl_specifier_seq*, int,
tree_node*, tree_node*, tree_node**)
???:0
0xa29b8d c_parse_file()
???:0
0xbb6bb2 c_common_parse_file()
???:0
