Extend loplugin:external to warn about classes

...following up on 314f15bff08b76bf96acf99141776ef64d2f1355 "Extend
loplugin:external to warn about enums".

Cases where free functions were moved into an unnamed namespace along with a
class, to not break ADL, are in:

filter/source/svg/svgexport.cxx
sc/source/filter/excel/xelink.cxx
sc/source/filter/excel/xilink.cxx
svx/source/sdr/contact/viewobjectcontactofunocontrol.cxx

All other free functions mentioning moved classes appear to be harmless and not
give rise to (silent, even) ADL breakage.  (One remaining TODO in
compilerplugins/clang/external.cxx is that derived classes are not covered by
computeAffectedTypes, even though they could also be affected by ADL-breakage---
but don't seem to be in any acutal case across the code base.)

For friend declarations using elaborate type specifiers, like

class C1 {};
class C2 { friend class C1; };

* If C2 (but not C1) is moved into an unnamed namespace, the friend declaration
must be changed to not use an elaborate type specifier (i.e., "friend C1;"; see
C++17 [namespace.memdef]/3: "If the name in a friend declaration is neither
qualified nor a template-id and the declaration is a function or an
elaborated-type-specifier, the lookup to determine whether the entity has been
previously declared shall not consider any scopes outside the innermost
enclosing namespace.")

* If C1 (but not C2) is moved into an unnamed namespace, the friend declaration
must be changed too, see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71882>
"elaborated-type-specifier friend not looked up in unnamed namespace".

Apart from that, to keep changes simple and mostly mechanical (which should help
avoid regressions), out-of-line definitions of class members have been left in
the enclosing (named) namespace.  But explicit specializations of class
templates had to be moved into the unnamed namespace to appease
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92598> "explicit specialization of
template from unnamed namespace using unqualified-id in enclosing namespace".

Also, accompanying declarations (of e.g. typedefs or static variables) that
could arguably be moved into the unnamed namespace too have been left alone.

And in some cases, mention of affected types in blacklists in other loplugins
needed to be adapted.

And sc/qa/unit/mark_test.cxx uses a hack of including other .cxx, one of which
is sc/source/core/data/segmenttree.cxx where e.g. ScFlatUInt16SegmentsImpl is
not moved into an unnamed namespace (because it is declared in
sc/inc/segmenttree.hxx), but its base ScFlatSegmentsImpl is.  GCC warns about
such combinations with enabled-by-default -Wsubobject-linkage, but "The compiler
doesn’t give this warning for types defined in the main .C file, as those are
unlikely to have multiple definitions."
(<https://gcc.gnu.org/onlinedocs/gcc-9.2.0/gcc/Warning-Options.html>)  The
warned-about classes also don't have multiple definitions in the given test, so
disable the warning when including the .cxx.

Change-Id: Ib694094c0d8168be68f8fe90dfd0acbb66a3f1e4
Reviewed-on: https://gerrit.libreoffice.org/83239
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

8 files changed, 24 insertions, 0 deletions

diff --git a/forms/source/component/Button.cxx b/forms/source/component/Button.cxx
index 31f87284d0d4..ffa29b1bb6ce 100644
--- a/forms/source/component/Button.cxx
+++ b/forms/source/component/Button.cxx
@@ -537,6 +537,7 @@ void SAL_CALL OButtonControl::removeActionListener(const Reference<XActionListen
     m_aActionListeners.removeInterface(_rxListener);
 }
 
+namespace {
 
 class DoPropertyListening
 {
@@ -555,6 +556,7 @@ public:
     void    handleListening( const OUString& _rPropertyName );
 };
 
+}
 
 DoPropertyListening::DoPropertyListening(
         const Reference< XInterface >& _rxComponent, const Reference< XPropertyChangeListener >& _rxListener,
diff --git a/forms/source/component/DatabaseForm.cxx b/forms/source/component/DatabaseForm.cxx
index f2b307c702ad..3bd03fce0b03 100644
--- a/forms/source/component/DatabaseForm.cxx
+++ b/forms/source/component/DatabaseForm.cxx
@@ -98,6 +98,8 @@ using namespace ::com::sun::star::util;
 namespace frm
 {
 
+namespace {
+
 class DocumentModifyGuard
 {
 public:
@@ -129,6 +131,8 @@ private:
     Reference< XModifiable2 >   m_xDocumentModify;
 };
 
+}
+
 // submitting and resetting html-forms asynchronously
 class OFormSubmitResetThread: public OComponentEventThread
 {
diff --git a/forms/source/component/FormComponent.cxx b/forms/source/component/FormComponent.cxx
index 7ab3e7732f7d..fb584d478ced 100644
--- a/forms/source/component/FormComponent.cxx
+++ b/forms/source/component/FormComponent.cxx
@@ -89,6 +89,8 @@ void ControlModelLock::addPropertyNotification( const sal_Int32 _nHandle, const
     m_aNewValues.push_back( _rNewValue );
 }
 
+namespace {
+
 class FieldChangeNotifier
 {
 public:
@@ -112,6 +114,8 @@ private:
     Reference< XPropertySet >   m_xOldField;
 };
 
+}
+
 // base class for form layer controls
 OControl::OControl( const Reference< XComponentContext >& _rxContext, const OUString& _rAggregateService, const bool _bSetDelegator )
             :OComponentHelper(m_aMutex)
diff --git a/forms/source/component/FormattedField.cxx b/forms/source/component/FormattedField.cxx
index 178cf037312d..805076b545d1 100644
--- a/forms/source/component/FormattedField.cxx
+++ b/forms/source/component/FormattedField.cxx
@@ -76,6 +76,8 @@ using namespace css::form::binding;
 
 namespace frm
 {
+namespace {
+
 class StandardFormatsSupplier : protected SvNumberFormatsSupplierObj, public ::utl::ITerminationListener
 {
 protected:
@@ -90,6 +92,9 @@ protected:
     virtual bool    queryTermination() const override;
     virtual void    notifyTermination() override;
 };
+
+}
+
 WeakReference< XNumberFormatsSupplier > StandardFormatsSupplier::s_xDefaultFormatsSupplier;
 StandardFormatsSupplier::StandardFormatsSupplier(const Reference< XComponentContext > & _rxContext,LanguageType _eSysLanguage)
     :SvNumberFormatsSupplierObj()
diff --git a/forms/source/component/imgprod.cxx b/forms/source/component/imgprod.cxx
index c1b72d90daed..848b2ce0629b 100644
--- a/forms/source/component/imgprod.cxx
+++ b/forms/source/component/imgprod.cxx
@@ -34,6 +34,7 @@
 #include <svtools/imageresourceaccess.hxx>
 #include <comphelper/processfactory.hxx>
 
+namespace {
 
 class ImgProdLockBytes : public SvLockBytes
 {
@@ -52,6 +53,7 @@ public:
     virtual ErrCode     Stat( SvLockBytesStat* ) const override;
 };
 
+}
 
 ImgProdLockBytes::ImgProdLockBytes( SvStream* pStm, bool bOwner ) :
         SvLockBytes( pStm, bOwner )
diff --git a/forms/source/helper/commandimageprovider.cxx b/forms/source/helper/commandimageprovider.cxx
index a40783149416..6569c8a4373e 100644
--- a/forms/source/helper/commandimageprovider.cxx
+++ b/forms/source/helper/commandimageprovider.cxx
@@ -52,6 +52,8 @@ namespace frm
 
     namespace ImageType = ::com::sun::star::ui::ImageType;
 
+    namespace {
+
     class DocumentCommandImageProvider : public ICommandImageProvider
     {
     public:
@@ -71,6 +73,7 @@ namespace frm
         Reference< XImageManager >    m_xModuleImageManager;
     };
 
+    }
 
     void DocumentCommandImageProvider::impl_init_nothrow( const Reference<XComponentContext>& _rContext, const Reference< XModel >& _rxDocument )
     {
diff --git a/forms/source/misc/InterfaceContainer.cxx b/forms/source/misc/InterfaceContainer.cxx
index ac86a12b0454..c318b936d8af 100644
--- a/forms/source/misc/InterfaceContainer.cxx
+++ b/forms/source/misc/InterfaceContainer.cxx
@@ -347,6 +347,7 @@ void SAL_CALL OInterfaceContainer::writeEvents(const Reference<XObjectOutputStre
         lcl_restoreEvents( aSave, m_xEventAttacher );
 }
 
+namespace {
 
 struct TransformEventTo52Format
 {
@@ -370,6 +371,7 @@ struct TransformEventTo52Format
     }
 };
 
+}
 
 void OInterfaceContainer::transformEvents()
 {
diff --git a/forms/source/misc/limitedformats.cxx b/forms/source/misc/limitedformats.cxx
index c079591e61b8..e7f0fb4cb352 100644
--- a/forms/source/misc/limitedformats.cxx
+++ b/forms/source/misc/limitedformats.cxx
@@ -76,6 +76,7 @@ namespace frm
         return s_aSystem;
     }
 
+    namespace {
 
     struct FormatEntry
     {
@@ -84,6 +85,7 @@ namespace frm
         LocaleType      eLocale;
     };
 
+    }
 
     static FormatEntry* lcl_getFormatTable(sal_Int16 nTableId)
     {