https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111923
Bug ID: 111923
Summary: default argument is not treated as a complete-class
context of a class
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: stsp at users dot sourceforge.net
Target Milestone: ---
The standard says:
https://eel.is/c++draft/class.mem.general#7.2
A complete-class context of a class (template) is a
(7.1)function body ([dcl.fct.def.general]),
(7.2)default argument ([dcl.fct.default]),
...
[Note 4: A complete-class context of a nested class is also a complete-class
context of any enclosing class, if the nested class is defined within the
member-specification of the enclosing class.
— end note]
I think this means that the following
code should compile:
struct A {
char a;
static constexpr int (*off_p)(int p) =
[](int off = offsetof(A, a)) static constexpr ->int { return off; };
};
But it fails with:
bad.cpp:6:22: error: invalid use of incomplete type ‘struct A’
Surprisingly, this code does actually compile:
struct A {
char a;
int (*off_p)(int p) =
[](int off = offsetof(A, a)) static constexpr ->int { return off; };
};
(the only difference is that off_p
is no longer static constexpr).
But I need this code to compile when
off_p is a static constexpr.
