C++: fix used template function parameters

It was missing colorizing and follow symbol template function parameters in case of:
* returning value
* use it as qualified name

Task-number: QTCREATORBUG-6861

Change-Id: I4226199e1f296cfe5a373783ebbc633e32fc9bcd
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/libs/cplusplus/CppDocument.cpp

@@ -175,6 +175,14 @@ protected:
     virtual bool visit(Block *symbol)
     { return process(symbol); }
 
+    virtual bool visit(Template *symbol)
+    {
+        if (symbol->declaration() && symbol->declaration()->isFunction())
+            return process(symbol);
+        else
+            return true;
+    }
+
     // Objective-C
     virtual bool visit(ObjCBaseClass *) { return false; }
     virtual bool visit(ObjCBaseProtocol *) { return false; }

src/plugins/cpptools/cppchecksymbols.cpp

@@ -408,6 +408,14 @@ Scope *CheckSymbols::enclosingScope() const
             if (funDef->symbol)
                 return funDef->symbol;
 
+        } else if (TemplateDeclarationAST *templateDeclaration = ast->asTemplateDeclaration()) {
+            if (DeclarationAST *decl = templateDeclaration->declaration) {
+                if (FunctionDefinitionAST *funDef = decl->asFunctionDefinition()) {
+                    if (funDef->symbol)
+                        return funDef->symbol;
+                }
+            }
+
         } else if (CompoundStatementAST *blockStmt = ast->asCompoundStatement()) {
             if (blockStmt->symbol)
                 return blockStmt->symbol;
@@ -869,7 +877,12 @@ ClassOrNamespace *CheckSymbols::checkNestedName(QualifiedNameAST *ast)
 
                 const Name *name = class_or_namespace_name->name;
                 binding = _context.lookupType(name, enclosingScope());
-                addType(binding, class_or_namespace_name);
+                if (binding)
+                    addType(binding, class_or_namespace_name);
+                else
+                    // for the case when we use template parameter as qualifier
+                    // e.g.: template <typename T> void fun() { T::type type; }
+                    accept(nested_name_specifier->class_or_namespace_name);
 
                 for (it = it->next; it; it = it->next) {
                     NestedNameSpecifierAST *nested_name_specifier = it->value;

src/plugins/cpptools/cppcompletion_test.cpp

@@ -1908,7 +1908,6 @@ void CppToolsPlugin::test_completion_typedef_using_templates1()
     QVERIFY(completions.contains(QLatin1String("bar")));
 }
 
-
 void CppToolsPlugin::test_completion_typedef_using_templates2()
 {
     TestData data;

tests/auto/cplusplus/checksymbols/tst_checksymbols.cpp

@@ -195,6 +195,7 @@ private slots:
     void test_checksymbols_highlightingTypeWhenUsingNamespaceClass_QTCREATORBUG7903_namespace();
     void test_checksymbols_highlightingTypeWhenUsingNamespaceClass_QTCREATORBUG7903_insideFunction();
     void test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORBUG9323_globalNamespace();
+    void test_checksymbols_highlightingUsedTemplateFunctionParameter_QTCREATORBUG6861();
     void test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORBUG9323_namespace();
     void test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORBUG9323_insideFunction();
 };
@@ -1702,6 +1703,7 @@ void tst_CheckSymbols::test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORB
 
     TestData::check(source, expectedUses);
 }
+
 void tst_CheckSymbols::test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORBUG9323_insideFunction()
 {
     const QByteArray source =
@@ -1725,5 +1727,30 @@ void tst_CheckSymbols::test_checksymbols_crashWhenUsingNamespaceClass_QTCREATORB
     TestData::check(source, expectedUses);
 }
 
+void tst_CheckSymbols::test_checksymbols_highlightingUsedTemplateFunctionParameter_QTCREATORBUG6861()
+{
+    const QByteArray source =
+            "template<class TEMP>\n"
+            "TEMP \n"
+            "foo(TEMP in)\n"
+            "{\n"
+            "    typename TEMP::type type;\n"
+            "}\n"
+           ;
+
+    const QList<Use> expectedUses = QList<Use>()
+            << Use(1, 16, 4, CppHighlightingSupport::TypeUse)
+            << Use(2, 1, 4, CppHighlightingSupport::TypeUse)
+            << Use(3, 1, 3, CppHighlightingSupport::FunctionUse)
+            << Use(3, 5, 4, CppHighlightingSupport::TypeUse)
+            << Use(3, 10, 2, CppHighlightingSupport::LocalUse)
+            << Use(5, 14, 4, CppHighlightingSupport::TypeUse)
+            << Use(5, 20, 4, CppHighlightingSupport::TypeUse)
+            << Use(5, 25, 4, CppHighlightingSupport::LocalUse)
+            ;
+
+    TestData::check(source, expectedUses);
+}
+
 QTEST_APPLESS_MAIN(tst_CheckSymbols)
 #include "tst_checksymbols.moc"