https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113916
Bug ID: 113916
Summary: gcc allows overriding a non-deleted private base class
dtor with a deleted defaulted dtor
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Keywords: accepts-invalid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rush102333 at gmail dot com
Target Milestone: ---
The following code seems invaild, because when the base class dtor is private,
it's natural that the explicitly defaulted derived class dtor should be defined
as deleted since it can't be defined as anything else. Then the question comes
that you can't override a non-deleted function(the virtual, though
inaccessible, base class dtor) with a deleted function(the explicitly defaulted
and implicitly deleted derived dtor).
Actually, we've confirmed that Clang rejects it. But it works well in
gcc_13.2.0.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
class Base
{
virtual ~Base() = default;
};
class Derived : public Base
{
~Derived() override = default;
};
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We're not sure but we tend to believe that it would more likely be a bug of
gcc.
Clang 17.0.1 rejects the code by complaining that:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<source>:8:5: warning: explicitly defaulted destructor is implicitly deleted
[-Wdefaulted-function-deleted]
8 | ~Derived() override = default;
| ^
<source>:6:17: note: destructor of 'Derived' is implicitly deleted because base
class 'Base' has an inaccessible destructor
6 | class Derived : public Base
| ^
<source>:8:27: note: replace 'default' with 'delete'
8 | ~Derived() override = default;
| ^~~~~~~
| delete
<source>:8:5: error: deleted function '~Derived' cannot override a non-deleted
function
8 | ~Derived() override = default;
| ^
<source>:3:13: note: overridden virtual function is here
3 | virtual ~Base() = default;
| ^
<source>:6:17: note: destructor of 'Derived' is implicitly deleted because base
class 'Base' has an inaccessible destructor
6 | class Derived : public Base
| ^
1 warning and 1 error generated.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Please check https://godbolt.org/z/4Tvc9Tfsz
