By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement . We’ll occasionally send you account related emails.

Issue

A deprecated member variable in a struct or class makes the entire entity deprecated, even if the user does not actually use the deprecated member (it may even be private). This is behaviour is not mentioned by the C++ reference .

In particular, the behaviour differs from MSVC and GCC:

Expected behaviour

The deprecation warning is raised only when the member variable is actually used by the user.

The difference in behaviour between Clang and MSVC is removed.

Alternative solution

Report bug to MSVC to remove the difference between Clang and MSVC.

Minimal example

A full minimal example can be found in this godbolt example . The code is also below. Note in particular, the implicit move constructor.

namespace {
struct Foo {
    [[deprecated]] bool bar{};
auto baz() {
    auto foo = Foo{};
    return foo;
Class
Note that the above also happens for otherwise fully private members in classes.
Non-triggering edge case
Note that if no (implicit) move constructor is used, the warning is not raised:
namespace {
struct Foo {
    [[deprecated]] bool bar{};
auto baz() {
    return Foo{};
Class
Note that the above bug also happens for otherwise fully private members in classes:
      changed the title
-Wdeprecated-declaration on members behaves differently from MSVC and GCC
-Wdeprecated-declaration on members behaves unexpectedly
    May 30, 2022
-Wdeprecated-declaration on members behaves unexpectedly
-Wdeprecated-declarations on members behaves unexpectedly
    May 30, 2022
  clang:diagnostics
  Request new/improved warning or error messages in the Clang compiler itself
    and removed
  new issue
  labels
    May 30, 2022