https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103672
Bug ID: 103672
Summary: using with template<template<class...> class> causes
internal compiler error
Product: gcc
Version: 11.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: turtlefight at ymail dot com
Target Milestone: ---
The following example results in an internal compiler error.
It does compile fine with clang and msvc.
Example Code:
#include <functional>
#include <memory>
template<class T>
struct unique {
auto operator()(auto&&... args) {
return std::make_unique<T>(std::forward<decltype(args)>(args)...);
}
};
template<template<class...> class T, class... Args>
using deduced_type = decltype(T{std::declval<Args>()...});
template<template<class> class F, template<class...> class T, class... Args>
auto make(Args&&... args) {
return F<deduced_type<T, Args...>>{}(std::forward<Args>(args)...);
}
template<class A, class B>
struct Foo { Foo(A,B) {} };
int main(){
auto foo_unique = make<unique, Foo>(1, 2);
}
Full Error Message:
<source>: In instantiation of 'auto make(Args&& ...) [with F = unique; T = Foo;
Args = {int, int}]':
<source>:24:40: required from here
<source>:16:41: internal compiler error: in tsubst, at cp/pt.c:15632
16 | return F<deduced_type<T, Args...>>{}(std::forward<Args>(args)...);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x21004e9 internal_error(char const*, ...)
???:0
0x7e96eb fancy_abort(char const*, int, char const*)
???:0
0xa5fde7 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0xa5d3af tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0xa89b76 tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
???:0
0xa5d954 tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0xa5eb8d tsubst(tree_node*, tree_node*, int, tree_node*)
???:0
0xa63a47 instantiate_decl(tree_node*, bool, bool)
???:0
0x904ebe maybe_instantiate_decl(tree_node*)
???:0
0x906980 mark_used(tree_node*, int)
???:0
0x819197 build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
???:0
0xaca89c finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
???:0
0xa29b8d c_parse_file()
???:0
0xbb6bb2 c_common_parse_file()
???:0
Godbolt Example: https://godbolt.org/z/rd4PdYrq8
What's interesting is that the code compiles without problems if a using
declaration is not used, e.g.:
template<template<class> class F, template<class...> class T, class... Args>
auto make(Args&&... args) {
return
F<decltype(T{std::declval<Args>()...})>{}(std::forward<Args>(args)...);
}
Godbolt Example: https://godbolt.org/z/Pd3Mjs8rG
