C++: fix dereferencing of nested type and 'auto'

Fixed case:
template<class T>
struct List
{
  struct iterator
  {
    T *operator->() { return &t; }
    T &operator*() { return t; }
    T t;
  };
  iterator begin() { return iterator(); }
};

struct Foo { int bar; };

void func()
{
  List<Foo> list;
  auto a = list.begin();
  (*a).; // code completion doesn't work
  a->; // code completion does not work
}

Task-number: QTCREATORBUG-13799
Change-Id: I38e4bfb2f5d728c0b24b0f18b3d78793e90d633b
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/libs/cplusplus/ResolveExpression.cpp

@@ -730,6 +730,7 @@ bool ResolveExpression::visit(SimpleNameAST *ast)
                 continue;
 
             TypeOfExpression exprTyper;
+            exprTyper.setExpandTemplates(true);
             Document::Ptr doc = _context.snapshot().document(QString::fromLocal8Bit(decl->fileName()));
             exprTyper.init(doc, _context.snapshot(), _context.bindings(),
                            QSet<const Declaration* >(_autoDeclarationsBeingResolved) << decl);
@@ -754,10 +755,12 @@ bool ResolveExpression::visit(SimpleNameAST *ast)
                 if (n == 0) {
                     item.setType(newType);
                     item.setScope(typeItems[n].scope());
+                    item.setBinding(typeItems[n].binding());
                 } else {
                     LookupItem newItem(item);
                     newItem.setType(newType);
                     newItem.setScope(typeItems[n].scope());
+                    newItem.setBinding(typeItems[n].binding());
                     newCandidates.push_back(newItem);
                 }
             }

src/plugins/cpptools/cppcompletion_test.cpp

@@ -2553,6 +2553,48 @@ void CppToolsPlugin::test_completion_data()
     ) << _("list.begin()->") << (QStringList()
         << QLatin1String("Foo")
         << QLatin1String("bar"));
+
+    QTest::newRow("dereference_of_nested_type_opertor_*_and_auto") << _(
+            "template<typename T>\n"
+            "struct QList\n"
+            "{\n"
+            "   struct iterator\n"
+            "   {\n"
+            "      T &operator*() { return t; }\n"
+            "      T t;\n"
+            "   };\n"
+            "   iterator begin() { return iterator(); }\n"
+            "};\n"
+            "struct Foo { int bar; };\n"
+            "void fun() {\n"
+            "   QList<Foo> list;\n"
+            "   auto a = list.begin();\n"
+            "   @\n"
+            "}\n"
+    ) << _("(*a).") << (QStringList()
+        << QLatin1String("Foo")
+        << QLatin1String("bar"));
+
+    QTest::newRow("dereference_of_nested_type_opertor_->_and_auto") << _(
+            "template<typename T>\n"
+            "struct QList\n"
+            "{\n"
+            "   struct iterator\n"
+            "   {\n"
+            "      T *operator->() { return &t; }\n"
+            "      T t;\n"
+            "   };\n"
+            "   iterator begin() { return iterator(); }\n"
+            "};\n"
+            "struct Foo { int bar; };\n"
+            "void fun() {\n"
+            "   QList<Foo> list;\n"
+            "   auto a = list.begin();\n"
+            "   @\n"
+            "}\n"
+    ) << _("a->") << (QStringList()
+        << QLatin1String("Foo")
+        << QLatin1String("bar"));
 }
 
 void CppToolsPlugin::test_completion_member_access_operator()