C++: Fix find usage to see Catch test functions bodies

Catch test functions defined with function-like macros.
To speed-up semantic analysis, find usages does not expand function-like
macros.
Semantic fails with "expected a function declarator" on such functions
and skips function body.
To avoid that, we create dummy function type specifically for this case

Change-Id: Ie2f2464ee57aa4dc86eed07b8b699458f95c0266
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/3rdparty/cplusplus/Bind.cpp

@@ -2252,6 +2252,19 @@ bool Bind::visit(FunctionDefinitionAST *ast)
     Function *fun = type->asFunctionType();
     ast->symbol = fun;
 
+    if (!fun && ast->declarator && ast->declarator->initializer)
+        if (ExpressionListParenAST *exprAst = ast->declarator->initializer->asExpressionListParen()) {
+            // this could be non-expanded function like macro, because
+            // for find usages we parse without expanding them
+            // So we create dummy function type here for findUsages to see function body
+            fun = control()->newFunction(0, nullptr);
+            fun->setStartOffset(tokenAt(exprAst->firstToken()).utf16charsBegin());
+            fun->setEndOffset(tokenAt(exprAst->lastToken() - 1).utf16charsEnd());
+
+            type = fun;
+            ast->symbol = fun;
+        }
+
     if (fun) {
         setDeclSpecifiers(fun, declSpecifiers);
         fun->setEndOffset(tokenAt(ast->lastToken() - 1).utf16charsEnd());

tests/auto/cplusplus/findusages/tst_findusages.cpp

@@ -126,6 +126,8 @@ private Q_SLOTS:
     void templatePartialSpecialization_2();
     void template_SFINAE_1();
     void variableTemplateInExpression();
+
+    void variadicMacros();
 };
 
 void tst_FindUsages::dump(const QList<Usage> &usages) const
@@ -1624,5 +1626,43 @@ int main(){
     QCOMPARE(find.usages().size(), 2);
 }
 
+void tst_FindUsages::variadicMacros()
+{
+    const QByteArray src =
+        R"(
+struct MyStruct { int value; };
+#define FOO( ... ) int foo()
+FOO(1) {
+    MyStruct s;
+    s.value;
+}
+int main(){}
+)";
+
+    Document::Ptr doc = Document::create("variadicMacros");
+    doc->setUtf8Source(src);
+    doc->parse();
+    doc->check();
+
+    QVERIFY(doc->diagnosticMessages().isEmpty());
+    QVERIFY(doc->globalSymbolCount() >= 1);
+
+    Snapshot snapshot;
+    snapshot.insert(doc);
+
+    Class *s = doc->globalSymbolAt(0)->asClass();
+    QVERIFY(s);
+    QCOMPARE(s->name()->identifier()->chars(), "MyStruct");
+    QCOMPARE(s->memberCount(), 1);
+
+    Declaration *sv = s->memberAt(0)->asDeclaration();
+    QVERIFY(sv);
+    QCOMPARE(sv->name()->identifier()->chars(), "value");
+
+    FindUsages find(src, doc, snapshot);
+    find(sv);
+    QCOMPARE(find.usages().size(), 2);
+}
+
 QTEST_APPLESS_MAIN(tst_FindUsages)
 #include "tst_findusages.moc"