loplugin:referencecasting look through more clang Types

Note that because of where the fix resides, loplugin:redundantcast
also notices a few more things.

Change-Id: I0b66047fadfff2c5ceafcbd3eab085de00d861a6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/120865
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 36 insertions, 2 deletions

diff --git a/compilerplugins/clang/plugin.cxx b/compilerplugins/clang/plugin.cxx
index c68eceb67c32..6f7c464aa161 100644
--- a/compilerplugins/clang/plugin.cxx
+++ b/compilerplugins/clang/plugin.cxx
@@ -11,6 +11,7 @@
 
 #include "plugin.hxx"
 
+#include <iostream>
 #include <cassert>
 #include <cstddef>
 #include <string>
@@ -736,8 +737,19 @@ bool hasCLanguageLinkageType(FunctionDecl const * decl) {
 static const CXXRecordDecl* stripTypeSugar(QualType qt)
 {
     const clang::Type* t = qt.getTypePtr();
-    while (auto elaboratedType = dyn_cast<ElaboratedType>(t))
-        t = elaboratedType->desugar().getTypePtr();
+    do
+    {
+        if (auto elaboratedType = dyn_cast<ElaboratedType>(t))
+            t = elaboratedType->desugar().getTypePtr();
+        else if (auto tsType = dyn_cast<TemplateSpecializationType>(t))
+            t = tsType->desugar().getTypePtr();
+        else if (auto sttpType = dyn_cast<SubstTemplateTypeParmType>(t))
+            t = sttpType->desugar().getTypePtr();
+        else if (auto tdType = dyn_cast<TypedefType>(t))
+            t = tdType->desugar().getTypePtr();
+        else
+            break;
+    } while(true);
     auto recordType = dyn_cast<RecordType>(t);
     if (!recordType)
         return nullptr;
diff --git a/compilerplugins/clang/test/referencecasting.cxx b/compilerplugins/clang/test/referencecasting.cxx
index a6850ed660ea..1b1e75f90cea 100644
--- a/compilerplugins/clang/test/referencecasting.cxx
+++ b/compilerplugins/clang/test/referencecasting.cxx
@@ -13,8 +13,10 @@
 #include "com/sun/star/uno/Sequence.hxx"
 #include "com/sun/star/uno/XInterface.hpp"
 #include "com/sun/star/io/XStreamListener.hpp"
+#include "com/sun/star/io/XInputStream.hpp"
 #include "com/sun/star/lang/XTypeProvider.hpp"
 #include "com/sun/star/lang/XComponent.hpp"
+#include "cppuhelper/implbase.hxx"
 #include "cppuhelper/weak.hxx"
 #include "rtl/ref.hxx"
 
@@ -192,4 +194,24 @@ void test14(css::uno::Sequence<css::uno::Reference<css::io::XStreamListener>> se
     }
 }
 
+namespace test15
+{
+class Foo : public cppu::WeakImplHelper<css::lang::XComponent, css::io::XInputStream>
+{
+    virtual ~Foo();
+    css::uno::Reference<css::lang::XTypeProvider> bar()
+    {
+        // expected-error@+1 {{the source reference is already a subtype of the destination reference, just use = [loplugin:referencecasting]}}
+        return css::uno::Reference<css::lang::XTypeProvider>(
+            static_cast<css::lang::XTypeProvider*>(this), css::uno::UNO_QUERY);
+    }
+    css::uno::Reference<css::io::XInputStream> bar2()
+    {
+        // expected-error@+1 {{the source reference is already a subtype of the destination reference, just use = [loplugin:referencecasting]}}
+        return css::uno::Reference<css::io::XInputStream>(static_cast<css::io::XInputStream*>(this),
+                                                          css::uno::UNO_QUERY);
+    }
+};
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */