C++ editor: support nested class of enclosing template

Fixing:
* highlighting
* tooltips
* find usage
* selecting

Task-number: QTCREATORBUG-8245
Change-Id: I6e900799e43126706125b7e424567fca2b2c223e
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>

src/libs/cplusplus/FindUsages.cpp

@@ -260,6 +260,8 @@ void FindUsages::checkExpression(unsigned startToken, unsigned endToken, Scope *
     if (! scope)
         scope = _currentScope;
 
+    // make possible to instantiate templates
+    typeofExpression.setExpandTemplates(true);
     const QList<LookupItem> results = typeofExpression(expression, scope, TypeOfExpression::Preprocess);
     reportResult(endToken, results);
 }

src/libs/cplusplus/LookupContext.h

@@ -281,7 +281,11 @@ public:
     static const Name *minimalName(Symbol *symbol, ClassOrNamespace *target, Control *control);
 
     void setExpandTemplates(bool expandTemplates)
-    { m_expandTemplates = expandTemplates; }
+    {
+        if (_bindings)
+            _bindings->setExpandTemplates(expandTemplates);
+        m_expandTemplates = expandTemplates;
+    }
 
 private:
     // The current expression.

src/plugins/cppeditor/cppeditor.cpp

@@ -819,6 +819,8 @@ static QList<int> lazyFindReferences(Scope *scope, QString code, Document::Ptr d
     TypeOfExpression typeOfExpression;
     snapshot.insert(doc);
     typeOfExpression.init(doc, snapshot);
+    // make possible to instantiate templates
+    typeOfExpression.setExpandTemplates(true);
     if (Symbol *canonicalSymbol = CanonicalSymbol::canonicalSymbol(scope, code, typeOfExpression))
         return CppModelManagerInterface::instance()->references(canonicalSymbol, typeOfExpression.context());
     return QList<int>();
@@ -1522,6 +1524,8 @@ CPPEditorWidget::Link CPPEditorWidget::findLinkAt(const QTextCursor &cursor,
 
     TypeOfExpression typeOfExpression;
     typeOfExpression.init(doc, snapshot);
+    // make possible to instantiate templates
+    typeOfExpression.setExpandTemplates(true);
     const QList<LookupItem> resolvedSymbols =
             typeOfExpression.reference(expression.toUtf8(), scope, TypeOfExpression::Preprocess);
 

src/plugins/cppeditor/cppelementevaluator.cpp

@@ -118,6 +118,8 @@ void CppElementEvaluator::execute()
 
         TypeOfExpression typeOfExpression;
         typeOfExpression.init(doc, snapshot);
+        // make possible to instantiate templates
+        typeOfExpression.setExpandTemplates(true);
         const QList<LookupItem> &lookupItems = typeOfExpression(expression.toUtf8(), scope);
         if (lookupItems.isEmpty())
             return;

src/plugins/cpptools/cppchecksymbols.cpp

@@ -324,6 +324,8 @@ CheckSymbols::CheckSymbols(Document::Ptr doc, const LookupContext &context, cons
     _potentialStatics = collectTypes.statics();
 
     typeOfExpression.init(_doc, _context.snapshot(), _context.bindings());
+    // make possible to instantiate templates
+    typeOfExpression.setExpandTemplates(true);
 }
 
 CheckSymbols::~CheckSymbols()

tests/auto/cplusplus/findusages/tst_findusages.cpp

@@ -90,6 +90,9 @@ private Q_SLOTS:
 //    void objc_methods();
 //    void objc_fields();
 //    void objc_classes();
+
+    // templates
+    void instantiateTemplateWithNestedClass();
 };
 
 void tst_FindUsages::inlineMethod()
@@ -351,5 +354,48 @@ void tst_FindUsages::qproperty_1()
     QCOMPARE(findUsages.references().size(), 2);
 }
 
+void tst_FindUsages::instantiateTemplateWithNestedClass()
+{
+    const QByteArray src = "\n"
+            "struct Foo\n"
+            "{ int bar; };\n"
+            "template <typename T>\n"
+            "struct Template\n"
+            "{\n"
+            "   struct Nested\n"
+            "   {\n"
+            "       T t;\n"
+            "   }nested;\n"
+            "};\n"
+            "void f()\n"
+            "{\n"
+            "   Template<Foo> templateFoo;\n"
+            "   templateFoo.nested.t.bar;\n"
+            "}\n"
+            ;
+
+    Document::Ptr doc = Document::create("simpleTemplate");
+    doc->setUtf8Source(src);
+    doc->parse();
+    doc->check();
+
+    QVERIFY(doc->diagnosticMessages().isEmpty());
+    QCOMPARE(doc->globalSymbolCount(), 3U);
+
+    Snapshot snapshot;
+    snapshot.insert(doc);
+
+    Class *classFoo = doc->globalSymbolAt(0)->asClass();
+    QVERIFY(classFoo);
+    QCOMPARE(classFoo->memberCount(), 1U);
+    Declaration *barDeclaration = classFoo->memberAt(0)->asDeclaration();
+    QVERIFY(barDeclaration);
+    QCOMPARE(barDeclaration->name()->identifier()->chars(), "bar");
+
+    FindUsages findUsages(src, doc, snapshot);
+    findUsages(barDeclaration);
+    QCOMPARE(findUsages.usages().size(), 2);
+}
+
 QTEST_APPLESS_MAIN(tst_FindUsages)
 #include "tst_findusages.moc"