Also suppress loplugin:flatten in C++ class member functions...

...invovling preprocessing conditionals, to actually make the unhelpful warning
on Windows about OleEmbeddedObject::changeState go away.  And while at it, make
the check for preprocessing conditionals more targeted (similar to
1084e8be "More targeted check for preprocessing
conditionals in loplugin:blockblock").

Change-Id: I0300e0a547e969520a90cd126ea8f788cc17560f
Reviewed-on: https://gerrit.libreoffice.org/42975Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

compilerplugins/clang/flatten.cxx

@@ -30,13 +30,6 @@ public:
         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
     }
 
-    bool TraverseFunctionDecl(FunctionDecl * decl) {
-        if (containsPreprocessingConditionalInclusion(decl->getSourceRange())) {
-            return true;
-        }
-        return RecursiveASTVisitor::TraverseFunctionDecl(decl);
-    }
-
     bool TraverseCXXCatchStmt(CXXCatchStmt * );
     bool VisitIfStmt(IfStmt const * );
 private:
@@ -115,6 +108,10 @@ bool Flatten::VisitIfStmt(IfStmt const * ifStmt)
     if (parentIfStmt && parentIfStmt->getElse() == ifStmt)
         return true;
 
+    if (containsPreprocessingConditionalInclusion(ifStmt->getSourceRange())) {
+        return true;
+    }
+
     auto throwExpr = containsSingleThrowExpr(ifStmt->getElse());
     if (throwExpr)
     {

compilerplugins/clang/test/flatten.cxx

@@ -56,13 +56,16 @@ void top4() {
 }
 
 void top5() {
-    // no warning expected
 #if 1
     if (foo() == 2) {
-        bar();
+        if (foo() == 3) { // expected-note {{if condition here [loplugin:flatten]}}
+            bar();
+        } else {
+            throw std::exception(); // expected-error {{unconditional throw in else branch, rather invert the condition, throw early, and flatten the normal case [loplugin:flatten]}}
+        }
     } else
 #endif
-        throw std::exception();
+        throw std::exception(); // no warning expected
 }
 
 int main() {