CppEditor: Prevent "Add Declaration" for existing template functions

class Foo
{
    template<class T>
    void func();
};

template<class T>
void Foo::func() {} // Add Declaration should not be triggered at all

Change-Id: Ifff733d8381177300dae017ae419200cfdf5c425
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cppeditor/cppeditorplugin.h

@@ -147,6 +147,7 @@ private slots:
     void test_quickfix_InsertDefFromDecl_unicodeIdentifier();
 
     void test_quickfix_InsertDeclFromDef();
+    void test_quickfix_InsertDeclFromDef_notTriggeredForTemplateFunc();
 
     void test_quickfix_AddIncludeForUndefinedIdentifier_data();
     void test_quickfix_AddIncludeForUndefinedIdentifier();

src/plugins/cppeditor/cppquickfix_test.cpp

@@ -2715,6 +2715,22 @@ void CppEditorPlugin::test_quickfix_InsertDeclFromDef()
     insertToSectionDeclFromDef("private slots", 5);
 }
 
+void CppEditorPlugin::test_quickfix_InsertDeclFromDef_notTriggeredForTemplateFunc()
+{
+    QByteArray contents =
+        "class Foo\n"
+        "{\n"
+        "    template<class T>\n"
+        "    void func();\n"
+        "};\n"
+        "\n"
+        "template<class T>\n"
+        "void Foo::fu@nc() {}\n";
+
+    InsertDeclFromDef factory;
+    QuickFixOperationTest(singleDocument(contents, ""), &factory);
+}
+
 void CppEditorPlugin::test_quickfix_AddIncludeForUndefinedIdentifier_data()
 {
     QTest::addColumn<QString>("headerPath");

src/plugins/cppeditor/cppquickfixes.cpp

@@ -2465,7 +2465,17 @@ void InsertDeclFromDef::match(const CppQuickFixInterface &interface, QuickFixOpe
     Function *fun = funDef->symbol;
     if (Class *matchingClass = isMemberFunction(interface.context(), fun)) {
         const QualifiedNameId *qName = fun->name()->asQualifiedNameId();
-        for (Symbol *s = matchingClass->find(qName->identifier()); s; s = s->next()) {
+        for (Symbol *symbol = matchingClass->find(qName->identifier());
+             symbol; symbol = symbol->next()) {
+            Symbol *s = symbol;
+            if (fun->enclosingScope()->isTemplate()) {
+                if (const Template *templ = s->type()->asTemplateType()) {
+                    if (Symbol *decl = templ->declaration()) {
+                        if (decl->type()->isFunctionType())
+                            s = decl;
+                    }
+                }
+            }
             if (!s->name()
                     || !qName->identifier()->match(s->identifier())
                     || !s->type()->isFunctionType())