The attribute may be applied to the declaration of
a non-static data member,
a concept, or
a template specialization.
Recommended practice: Implementations should use the deprecated attribute to produce a diagnostic
message in case the program refers to a name or entity other than to declare it, after a
declaration that specifies the attribute.
The diagnostic message should include the text provided
within the attribute-argument-clause of any deprecated attribute applied
to the name or entity.