https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120831
Bug ID: 120831
Summary: Raise a diagnostic when a class/struct that is marked
as final introduces a virtual method
Product: gcc
Version: 15.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: arash at partow dot net
Target Milestone: ---
In clang++ v21, the following code correctly raises the diagnostic below:
struct base
{
virtual ~base() = default;
virtual void foo() {}
};
struct derived final : public base
{
void foo() override {}
virtual void bar() {} // raise error due to this.
};
Diagnostic
<source>:11:18: error: virtual method 'bar' is inside a 'final' class and can
never be overridden [-Werror,-Wunnecessary-virtual-specifier]
11 | virtual void bar() {}
Where the arguments are:
-pedantic-errors -Wall -Wextra -Werror -Wcast-align -Wcast-qual
-Wctor-dtor-privacy -Wint-in-bool-context -Wmissing-declarations
-Wredundant-decls -Wundef -Wunused-function -Wnon-virtual-dtor
-Woverloaded-virtual -Wno-missing-template-arg-list-after-template-kw
However afaict, G++ does not provide such a diagnostic - unless I'm possibly
missing the appropriate option.
It should be noted that the -Wunnecessary-virtual-specifier seems to, for now,
be clang++ specific.
https://godbolt.org/z/rPG6r8EPa
