C++: fix auto completion for template parameters

Fix auto completion for the case when template parameter should be
found somewhere of scope of template instantiation declaration.
Example:
struct A
{
    void foo();
    struct B
    {
        int b;
    };
};

template<typename T>
struct Template
{
    T* get() { return 0; }
    T t;
};

void A::foo()
{
    Template<B> templ;
    templ.get()->//no autocompletion
    templ.t.//no autocompletion
}

Task-number: QTCREATORBUG-8852
Task-number: QTCREATORBUG-9169
Change-Id: I56b40776e66740f995ae6fc5d69e3c50139a3af2
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/libs/cplusplus/ResolveExpression.cpp

@@ -142,11 +142,13 @@ void ResolveExpression::addResults(const QList<LookupItem> &items)
     _results += items;
 }
 
-void ResolveExpression::addResult(const FullySpecifiedType &ty, Scope *scope)
+void ResolveExpression::addResult(const FullySpecifiedType &ty, Scope *scope,
+                                  ClassOrNamespace *binding)
 {
     LookupItem item;
     item.setType(ty);
     item.setScope(scope);
+    item.setBinding(binding);
 
     _results.append(item);
 }
@@ -713,7 +715,7 @@ bool ResolveExpression::visit(CallAST *ast)
 
         } else if (Function *funTy = ty->asFunctionType()) {
             if (maybeValidPrototype(funTy, actualArgumentCount))
-                addResult(funTy->returnType().simplified(), scope);
+                addResult(funTy->returnType().simplified(), scope, result.binding());
 
         } else if (Class *classTy = ty->asClassType()) {
             // Constructor call
@@ -1014,53 +1016,77 @@ ClassOrNamespace *ResolveExpression::baseExpression(const QList<LookupItem> &bas
                 FullySpecifiedType type = ptrTy->elementType();
                 if (! ty->isPointerType())
                     type = ty;
+
+                if (ClassOrNamespace *binding
+                        = findClassForTemplateParameterInExpressionScope(r.binding(),
+                                                                         type)) {
+                    return binding;
+                }
                 if (ClassOrNamespace *binding = findClass(type, scope))
                     return binding;
 
             } else if (PointerType *ptrTy = ty->asPointerType()) {
                 FullySpecifiedType type = ptrTy->elementType();
+                if (ClassOrNamespace *binding
+                        = findClassForTemplateParameterInExpressionScope(r.binding(),
+                                                                         type)) {
+                    return binding;
+                }
                 if (ClassOrNamespace *binding = findClass(type, scope))
                     return binding;
 
-            } else if (ClassOrNamespace *binding = findClass(ty, scope)) {
-                // lookup for overloads of operator->
+            } else {
+                ClassOrNamespace *binding
+                        = findClassForTemplateParameterInExpressionScope(r.binding(),
+                                                                         ty);
+                if (! binding)
+                    binding = findClass(ty, scope);
 
-                const OperatorNameId *arrowOp = control()->operatorNameId(OperatorNameId::ArrowOp);
-                foreach (const LookupItem &r, binding->find(arrowOp)) {
-                    Symbol *overload = r.declaration();
-                    if (! overload)
-                        continue;
-                    Scope *functionScope = overload->enclosingScope();
+                if (binding){
+                    // lookup for overloads of operator->
 
-                    if (overload->type()->isFunctionType()) {
-                        FullySpecifiedType overloadTy = instantiate(binding->templateId(), overload);
-                        Function *instantiatedFunction = overloadTy->asFunctionType();
-                        Q_ASSERT(instantiatedFunction != 0);
-
-                        FullySpecifiedType retTy = instantiatedFunction->returnType().simplified();
-
-                        typedefsResolver.resolve(&retTy, &functionScope, r.binding());
-
-                        if (! retTy->isPointerType() && ! retTy->isNamedType())
+                    const OperatorNameId *arrowOp
+                            = control()->operatorNameId(OperatorNameId::ArrowOp);
+                    foreach (const LookupItem &r, binding->find(arrowOp)) {
+                        Symbol *overload = r.declaration();
+                        if (! overload)
                             continue;
+                        Scope *functionScope = overload->enclosingScope();
 
-                        if (PointerType *ptrTy = retTy->asPointerType())
-                            retTy = ptrTy->elementType();
+                        if (overload->type()->isFunctionType()) {
+                            FullySpecifiedType overloadTy
+                                    = instantiate(binding->templateId(), overload);
+                            Function *instantiatedFunction = overloadTy->asFunctionType();
+                            Q_ASSERT(instantiatedFunction != 0);
 
-                        if (ClassOrNamespace *retBinding = findClass(retTy, functionScope))
-                            return retBinding;
+                            FullySpecifiedType retTy
+                                    = instantiatedFunction->returnType().simplified();
 
-                        if (scope != functionScope) {
-                            if (ClassOrNamespace *retBinding = findClass(retTy, scope))
+                            typedefsResolver.resolve(&retTy, &functionScope, r.binding());
+
+                            if (! retTy->isPointerType() && ! retTy->isNamedType())
+                                continue;
+
+                            if (PointerType *ptrTy = retTy->asPointerType())
+                                retTy = ptrTy->elementType();
+
+                            if (ClassOrNamespace *retBinding = findClass(retTy, functionScope))
                                 return retBinding;
-                        }
 
-                        if (ClassOrNamespace *origin = binding->instantiationOrigin()) {
-                            foreach (Symbol *originSymbol, origin->symbols()) {
-                                Scope *originScope = originSymbol->asScope();
-                                if (originScope && originScope != scope && originScope != functionScope) {
-                                    if (ClassOrNamespace *retBinding = findClass(retTy, originScope))
-                                        return retBinding;
+                            if (scope != functionScope) {
+                                if (ClassOrNamespace *retBinding = findClass(retTy, scope))
+                                    return retBinding;
+                            }
+
+                            if (ClassOrNamespace *origin = binding->instantiationOrigin()) {
+                                foreach (Symbol *originSymbol, origin->symbols()) {
+                                    Scope *originScope = originSymbol->asScope();
+                                    if (originScope && originScope != scope
+                                            && originScope != functionScope) {
+                                        if (ClassOrNamespace *retBinding
+                                                = findClass(retTy, originScope))
+                                            return retBinding;
+                                    }
                                 }
                             }
                         }
@@ -1078,6 +1104,12 @@ ClassOrNamespace *ResolveExpression::baseExpression(const QList<LookupItem> &bas
                 }
             }
 
+            if (ClassOrNamespace *binding
+                    = findClassForTemplateParameterInExpressionScope(r.binding(),
+                                                                     ty)) {
+                return binding;
+            }
+
             ClassOrNamespace *enclosingTemplateInstantiation = 0;
             if (ClassOrNamespace *binding = r.binding()) {
                 if (binding->instantiationOrigin())
@@ -1092,6 +1124,24 @@ ClassOrNamespace *ResolveExpression::baseExpression(const QList<LookupItem> &bas
     return 0;
 }
 
+ClassOrNamespace *ResolveExpression::findClassForTemplateParameterInExpressionScope(
+        ClassOrNamespace *resultBinding,
+        const FullySpecifiedType &ty) const
+{
+    if (resultBinding && resultBinding->instantiationOrigin()) {
+        if (ClassOrNamespace *origin = resultBinding->instantiationOrigin()) {
+            foreach (Symbol *originSymbol, origin->symbols()) {
+                if (Scope *originScope = originSymbol->asScope()) {
+                    if (ClassOrNamespace *retBinding = findClass(ty, originScope))
+                        return retBinding;
+                }
+            }
+        }
+    }
+
+    return 0;
+}
+
 FullySpecifiedType ResolveExpression::instantiate(const Name *className, Symbol *candidate) const
 {
     return DeprecatedGenTemplateInstance::instantiate(className, candidate,

src/libs/cplusplus/ResolveExpression.h

@@ -71,7 +71,7 @@ protected:
 
     void thisObject();
 
-    void addResult(const FullySpecifiedType &ty, Scope *scope);
+    void addResult(const FullySpecifiedType &ty, Scope *scope, ClassOrNamespace *binding = 0);
     void addResults(const QList<Symbol *> &symbols);
     void addResults(const QList<LookupItem> &items);
 
@@ -126,6 +126,10 @@ protected:
 
 
 private:
+    ClassOrNamespace *findClassForTemplateParameterInExpressionScope(
+            ClassOrNamespace *resultBinding,
+            const FullySpecifiedType &ty) const;
+
     Scope *_scope;
     const LookupContext& _context;
     Bind bind;

src/plugins/cpptools/cppcompletion_test.cpp

@@ -3027,3 +3027,211 @@ void CppToolsPlugin::test_completion_local_type_and_member_6()
     QVERIFY(completions.contains(QLatin1String("OtherType")));
     QVERIFY(completions.contains(QLatin1String("otherTypeMember")));
 }
+
+void CppToolsPlugin::test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG9169_1()
+{
+    TestData data;
+    data.srcText =
+            "struct A\n"
+            "{\n"
+            "    void foo();\n"
+            "    struct B\n"
+            "    {\n"
+            "        int b;\n"
+            "    };\n"
+            "};\n"
+            "template<typename T>\n"
+            "struct Template\n"
+            "{\n"
+            "    T* get();\n"
+            "};\n"
+            "namespace foo\n"
+            "{\n"
+            "    struct B\n"
+            "    {\n"
+            "        int foo_b;\n"
+            "    };\n"
+            "}\n"
+            "using namespace foo;\n"
+            "void A::foo()\n"
+            "{\n"
+            "    Template<B> templ;\n"
+            "    @\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("templ.get()->");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 2);
+    QVERIFY(completions.contains(QLatin1String("B")));
+    QVERIFY(completions.contains(QLatin1String("b")));
+}
+
+void CppToolsPlugin::test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG9169_2()
+{
+    TestData data;
+    data.srcText =
+            "struct A\n"
+            "{\n"
+            "    void foo();\n"
+            "    struct B\n"
+            "    {\n"
+            "        int b;\n"
+            "    };\n"
+            "};\n"
+            "template<typename T>\n"
+            "struct Template\n"
+            "{\n"
+            "    T t;\n"
+            "};\n"
+            "namespace foo\n"
+            "{\n"
+            "    struct B\n"
+            "    {\n"
+            "        int foo_b;\n"
+            "    };\n"
+            "}\n"
+            "using namespace foo;\n"
+            "void A::foo()\n"
+            "{\n"
+            "    Template<B> templ;\n"
+            "    @\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("templ.t.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 2);
+    QVERIFY(completions.contains(QLatin1String("B")));
+    QVERIFY(completions.contains(QLatin1String("b")));
+}
+
+void CppToolsPlugin::test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_1()
+{
+    TestData data;
+    data.srcText =
+            "template <typename T>\n"
+            "struct QList\n"
+            "{\n"
+            "    T at(int i) const;\n"
+            "};\n"
+            "namespace ns\n"
+            "{\n"
+            "    struct Foo { int bar; };\n"
+            "    void foo()\n"
+            "    {\n"
+            "        QList<Foo> list;\n"
+            "       @\n"
+            "       // padding so we get the scope right\n"
+            "    }\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("list.at(0).");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 2);
+    QVERIFY(completions.contains(QLatin1String("Foo")));
+    QVERIFY(completions.contains(QLatin1String("bar")));
+}
+
+void CppToolsPlugin::test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_2()
+{
+    TestData data;
+    data.srcText =
+            "template <typename T>\n"
+            "struct QList\n"
+            "{\n"
+            "    T at(int i) const;\n"
+            "};\n"
+            "namespace ns\n"
+            "{\n"
+            "    struct Foo { int bar; };\n"
+            "    namespace nested\n"
+            "    {\n"
+            "       void foo()\n"
+            "       {\n"
+            "           QList<Foo> list;\n"
+            "           @\n"
+            "           // padding so we get the scope right\n"
+            "       }\n"
+            "    }\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("list.at(0).");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 2);
+    QVERIFY(completions.contains(QLatin1String("Foo")));
+    QVERIFY(completions.contains(QLatin1String("bar")));
+}
+
+void CppToolsPlugin::test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_3()
+{
+    TestData data;
+    data.srcText =
+            "template <typename T>\n"
+            "struct QList\n"
+            "{\n"
+            "    T at(int i) const;\n"
+            "};\n"
+            "namespace ns\n"
+            "{\n"
+            "    struct Foo { int bar; };\n"
+            "}\n"
+            "void foo()\n"
+            "{\n"
+            "    using namespace ns;\n"
+            "    QList<Foo> list;\n"
+            "    @\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("list.at(0).");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 2);
+    QVERIFY(completions.contains(QLatin1String("Foo")));
+    QVERIFY(completions.contains(QLatin1String("bar")));
+}

src/plugins/cpptools/cpptoolsplugin.h

@@ -156,6 +156,12 @@ private slots:
     void test_completion_enum_inside_block_inside_function_QTCREATORBUG5456();
     void test_completion_enum_inside_function_QTCREATORBUG5456();
 
+    void test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG9169_1();
+    void test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG9169_2();
+    void test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_1();
+    void test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_2();
+    void test_completion_template_parameter_defined_inside_scope_of_declaration_QTCREATORBUG8852_3();
+
     //lambda
     void test_completion_lambdaCalls_1();
     void test_completion_lambdaCalls_2();