https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123844
Bug ID: 123844
Summary: Function default arguments cause template
instantiation
Product: gcc
Version: 15.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: bolsh.andrey at yandex dot ru
Target Milestone: ---
GCC reports an error due to incomplete type for the following code:
class Incomplete;
template <class T>
T* getPtr() {
return new T;
}
void Fn(Incomplete* = getPtr<Incomplete>());
I think it is wrong because it is stated in [temp.inst] p.9:
The use of a template specialization in a default argument shall not cause the
template to be implicitly instantiated except that a class template may be
instantiated where its complete type is needed to determine the correctness of
the default argument. The use of a default argument in a function call causes
specializations in the default argument to be implicitly instantiated.
https://timsong-cpp.github.io/cppwp/n4659/temp.inst#9
Clang and MSVC both compile such code: https://godbolt.org/z/dcjenvxxT
