https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86565
Bug ID: 86565
Summary: failing to instantiate all of a local class
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: zhonghao at pku dot org.cn
Target Milestone: ---
The code is as follow:
template<typename T> void f() {
struct S { void g(int n = T::error) noexcept(T::error); };
}
template void f<int>();
g++ accepts it, but clang++ rejects it:
code0.cpp:2:28: error: type 'int' cannot be used prior to '::' because it has
no members
struct S { void g(int n = T::error) noexcept(T::error); };
^
code0.cpp:2:9: note: in instantiation of member class 'S' requested here
struct S { void g(int n = T::error) noexcept(T::error); };
^
code0.cpp:4:15: note: in instantiation of function template specialization
'f<int>' requested here
template void f<int>();
^
code0.cpp:2:47: error: type 'int' cannot be used prior to '::' because it has
no members
struct S { void g(int n = T::error) noexcept(T::error); };
^
2 errors generated.
g++ should reject this, because instantiating a function is supposed to
instantiate everything within the function, even pieces of a local class.
(Incidentally, failing to do this can lead to the "decl not instantiated in
this scope" assertion.)
