Avoid usage of incomplete types in member functions defined in-class

...that started to fail now at least with clang-cl (where the MSVC rules when to
emit inline member function definitions are more aggressive than for other ABIs)
with --with-latest-c++ and --with-visual-studio=2022 (where usage of incomplete
types in std::vector now triggered

> In file included from C:/lo-clang/core/slideshow/source/engine/opengl/TransitionerImpl.cxx:31:
> In file included from C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\memory:11:
> In file included from C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\exception:12:
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\type_traits(744,50): error: incomplete type 'Primitive' used in type trait expression
> struct is_trivially_destructible : bool_constant<__is_trivially_destructible(_Ty)> {
>                                                  ^
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\type_traits(59,53): note: in instantiation of template class 'std::is_trivially_destructible<Primitive>' requested here
> struct conjunction<_First, _Rest...> : _Conjunction<_First::value, _First, _Rest...>::type {
>                                                     ^
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\type_traits(64,44): note: in instantiation of template class 'std::conjunction<std::is_trivially_destructible<Primitive>, std::disjunction<std::_Is_default_allocator<std::allocator<Primitive>>, std::_Has_no_alloc_destroy<std::allocator<Primitive>, Primitive *>>>' requested here
> _INLINE_VAR constexpr bool conjunction_v = conjunction<_Traits...>::value;
>                                            ^
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\xmemory(934,20): note: in instantiation of variable template specialization 'std::conjunction_v<std::is_trivially_destructible<Primitive>, std::disjunction<std::_Is_default_allocator<std::allocator<Primitive>>, std::_Has_no_alloc_destroy<std::allocator<Primitive>, Primitive *>>>' requested here
>     if constexpr (!conjunction_v<is_trivially_destructible<_Ty>, _Uses_default_destroy<_Alloc, _Ty*>>) {
>                    ^
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\vector(1632,13): note: in instantiation of function template specialization 'std::_Destroy_range<std::allocator<Primitive>>' requested here
>             _Destroy_range(_Myfirst, _Mylast, _Al);
>             ^
> C:/PROGRA~1/MIB055~1/2022/Preview/VC/Tools/MSVC/1430~1.305/Include\vector(583,9): note: in instantiation of member function 'std::vector<Primitive>::_Tidy' requested here
>         _Tidy();
>         ^
> C:/lo-clang/core/slideshow/source/engine/opengl/TransitionImpl.hxx(74,5): note: in instantiation of member function 'std::vector<Primitive>::~vector' requested here
>     TransitionScene(
>     ^
> C:/lo-clang/core/slideshow/source/engine/opengl/TransitionImpl.hxx(42,7): note: forward declaration of 'Primitive'
> class Primitive;
>       ^

etc.).

Which in turn required tweaking of loplugin:unnecessaryoverride to avoid false

> In file included from C:/lo-clang/core/slideshow/source/engine/opengl/TransitionerImpl.cxx:67:
> C:/lo-clang/core/slideshow/source/engine/opengl/TransitionImpl.hxx(389,18): error: unnecessary user-declared destructor [loplugin:unnecessaryoverride]
> TransitionScene::~TransitionScene() = default;
> ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
> C:/lo-clang/core/slideshow/source/engine/opengl/TransitionImpl.hxx(81,12): note: declared here [loplugin:unnecessaryoverride]
>     inline ~TransitionScene();
>     ~~~~~~~^~~~~~~~~~~~~~~~~~

Change-Id: Ia72fb44e6e92ff47376d7b7159c0df7cbf883b69
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/123648
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

2 files changed, 7 insertions, 3 deletions

diff --git a/compilerplugins/clang/test/unnecessaryoverride-dtor.cxx b/compilerplugins/clang/test/unnecessaryoverride-dtor.cxx
index b54957be2d7a..8ed472749105 100644
--- a/compilerplugins/clang/test/unnecessaryoverride-dtor.cxx
+++ b/compilerplugins/clang/test/unnecessaryoverride-dtor.cxx
@@ -78,10 +78,10 @@ struct DefaultDerived1: VirtualBase {
 };
 
 struct DefaultDerived2: VirtualBase {
-    ~DefaultDerived2() override; // expected-note {{declared here [loplugin:unnecessaryoverride]}}
+    ~DefaultDerived2() override;
 };
 
-DefaultDerived2::~DefaultDerived2() = default; // expected-error {{unnecessary user-declared destructor [loplugin:unnecessaryoverride]}}
+DefaultDerived2::~DefaultDerived2() = default;
 
 struct EmptyDerived1: VirtualBase {
     ~EmptyDerived1() override {}; // expected-error {{unnecessary user-declared destructor [loplugin:unnecessaryoverride]}}
diff --git a/compilerplugins/clang/unnecessaryoverride.cxx b/compilerplugins/clang/unnecessaryoverride.cxx
index 6523170105a2..0641339d4e6f 100644
--- a/compilerplugins/clang/unnecessaryoverride.cxx
+++ b/compilerplugins/clang/unnecessaryoverride.cxx
@@ -200,7 +200,11 @@ bool UnnecessaryOverride::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
         {
             return true;
         }
-        if (!methodDecl->isExplicitlyDefaulted()) {
+        if (methodDecl->isExplicitlyDefaulted()) {
+            if (methodDecl->getPreviousDecl() != nullptr) {
+                return true;
+            }
+        } else {
             if (!methodDecl->doesThisDeclarationHaveABody()
                 || methodDecl->isLateTemplateParsed())
             {