https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97661
Bug ID: 97661
Summary: Bogus error message about initializing a using
declaration
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: markus.boeck02 at gmail dot com
Target Milestone: ---
Following code produces an error message I can't quite decipher. The code to my
knowledge is also correct and compiles with clang and MSVC:
template <class...Args>
class Base
{
};
class Derived : public Base<int,double,float>
{
};
template <class...Args>
struct DeduceArgs
{
Base<Args...>* p;
using type = Base<Args...>;
};
template <class ...Args>
DeduceArgs(Base<Args...>*) -> DeduceArgs<Args...>;
template <class T>
constexpr bool always_false = false;
#include <utility>
template <class T,class U = typename
decltype(DeduceArgs{std::declval<T*>()})::type>
class Deleter
{
static_assert(always_false<T>);
};
template <class Derived,class...Args>
class Deleter<Derived,Base<Args...>>
{
public:
void operator()(Derived* pointer) const noexcept
{
delete pointer;
}
};
#include <memory>
template <class T>
using IntrVarPtr = std::unique_ptr<T,Deleter<T>>;
int main()
{
IntrVarPtr<Derived> ptr;
}
The error message I receive is:
<source>: In substitution of 'template<class T> using IntrVarPtr =
std::unique_ptr<T, Deleter<T> > [with T = Derived]':
<source>:54:23: required from here
<source>:50:7: error: initializer for 'Base<int, double, float>' must be
brace-enclosed
50 | using IntrVarPtr = std::unique_ptr<T,Deleter<T>>;
| ^~~~~~~~~~
Corresponding godbolt link: https://godbolt.org/z/eK8fex
