https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102002
Bug ID: 102002
Summary: spec requires typename can be dropped when used as
template function return type consisting of template
parameter which is at global scope
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nickhuang99 at hotmail dot com
Target Milestone: ---
Spec considers *typename* can be dropped when there is no ambiguous of
regarding identifier as type. And
example(https://timsong-cpp.github.io/cppwp/temp.res#general-example-5) shows
this OK.
template<class T> T::R f();//OK, return type of a function declaration at
global scope
However, all compilers including GCC, clang, MSVC++ complains missing typename
because
error: need ‘typename’ before ‘T::R’ because ‘T’ is a dependent scope
1 | template<class T> T::R f();
| ^
| typename
Here I quote spec(https://timsong-cpp.github.io/cppwp/temp.res#general-4.1):
A qualified or unqualified name is said to be in a type-only context if it
is the terminal name of
a typename-specifier, nested-name-specifier, elaborated-type-specifier,
class-or-decltype
...
I understand this relaxation of enforcing *typename* is not so critical. Still
it is nice to strictly follow spec.
