Avoid broken static_cast

...from SvtValueItemAcc to unrelated ValueItemAcc in ~SvtValueSetItem.  The
Svt* classes had been copied from the non-Svt* ones in
4883fd31 "weld ScTabBgColorDlg", but this
static_cast had apparently been missed when copying ~SvtValueSetItem from
~ValueSetItem (and the originally copied SvtValueItemAcc::ParentDestroyed had
later been removed with d4d03761
"loplugin:unusedmethods").  But the static_cast in ~ValueSetItem would never
have been necessary in the first place (though that needs partial reversal of
508c95f1 "improve passstuffbyref return
analysis", which had unhelpfully changed ValueSetItem::GetAccessible to return a
reference).

Change-Id: If1c9bb617ac4ad3c24371729504f9082594c048f
Reviewed-on: https://gerrit.libreoffice.org/72914
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

svtools/source/control/valueacc.cxx

@@ -50,17 +50,17 @@ ValueSetItem::~ValueSetItem()
 {
     if( mxAcc.is() )
     {
-        static_cast< ValueItemAcc* >( mxAcc.get() )->ParentDestroyed();
+        mxAcc->ParentDestroyed();
     }
 }
 
 
-uno::Reference< accessibility::XAccessible > const & ValueSetItem::GetAccessible( bool bIsTransientChildrenDisabled )
+uno::Reference< accessibility::XAccessible > ValueSetItem::GetAccessible( bool bIsTransientChildrenDisabled )
 {
     if( !mxAcc.is() )
         mxAcc = new ValueItemAcc( this, bIsTransientChildrenDisabled );
 
-    return mxAcc;
+    return mxAcc.get();
 }
 
 SvtValueSetItem::SvtValueSetItem( SvtValueSet& rParent )
@@ -77,16 +77,16 @@ SvtValueSetItem::~SvtValueSetItem()
 {
     if( mxAcc.is() )
     {
-        static_cast< ValueItemAcc* >( mxAcc.get() )->ParentDestroyed();
+        mxAcc.get()->ParentDestroyed();
     }
 }
 
-uno::Reference< accessibility::XAccessible > const & SvtValueSetItem::GetAccessible( bool bIsTransientChildrenDisabled )
+uno::Reference< accessibility::XAccessible > SvtValueSetItem::GetAccessible( bool bIsTransientChildrenDisabled )
 {
     if( !mxAcc.is() )
         mxAcc = new SvtValueItemAcc( this, bIsTransientChildrenDisabled );
 
-    return mxAcc;
+    return mxAcc.get();
 }
 
 ValueSetAcc::ValueSetAcc( ValueSet* pParent ) :
@@ -1073,6 +1073,12 @@ SvtValueItemAcc::~SvtValueItemAcc()
 {
 }
 
+void SvtValueItemAcc::ParentDestroyed()
+{
+    const ::osl::MutexGuard aGuard( maMutex );
+    mpParent = nullptr;
+}
+
 namespace
 {
     class theSvtValueItemAccUnoTunnelId : public rtl::Static< UnoTunnelIdInit, theSvtValueItemAccUnoTunnelId > {};

svtools/source/control/valueimp.hxx

@@ -47,7 +47,9 @@ enum ValueSetItemType
     VALUESETITEM_USERDRAW
 };
 
+class ValueItemAcc;
 class ValueSet;
+class SvtValueItemAcc;
 class SvtValueSet;
 
 struct ValueSetItem
@@ -60,12 +62,12 @@ struct ValueSetItem
     Color               maColor;
     OUString            maText;
     void*               mpData;
-    css::uno::Reference< css::accessibility::XAccessible > mxAcc;
+    rtl::Reference< ValueItemAcc > mxAcc;
 
     explicit ValueSetItem( ValueSet& rParent );
     ~ValueSetItem();
 
-    css::uno::Reference< css::accessibility::XAccessible > const &
+    css::uno::Reference< css::accessibility::XAccessible >
                         GetAccessible( bool bIsTransientChildrenDisabled );
 };
 
@@ -79,12 +81,12 @@ struct SvtValueSetItem
     Color               maColor;
     OUString            maText;
     void*               mpData;
-    css::uno::Reference< css::accessibility::XAccessible > mxAcc;
+    rtl::Reference< SvtValueItemAcc > mxAcc;
 
     explicit SvtValueSetItem( SvtValueSet& rParent );
     ~SvtValueSetItem();
 
-    css::uno::Reference< css::accessibility::XAccessible > const &
+    css::uno::Reference< css::accessibility::XAccessible >
                         GetAccessible( bool bIsTransientChildrenDisabled );
 };
 
@@ -410,6 +412,8 @@ public:
     SvtValueItemAcc(SvtValueSetItem* pParent, bool bIsTransientChildrenDisabled);
     virtual ~SvtValueItemAcc() override;
 
+    void    ParentDestroyed();
+
     void    FireAccessibleEvent( short nEventId, const css::uno::Any& rOldValue, const css::uno::Any& rNewValue );
 
     static SvtValueItemAcc* getImplementation( const css::uno::Reference< css::uno::XInterface >& rxData ) throw();