C++: Handle recursive using/typedef declarations

Remember using/typedef declarations we have already looked up and
stop if we try it again.

Change-Id: I91bf0aef4df18539a47d015f0113543aef1f692a
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
(cherry picked from commit 50a900e509)

src/libs/cplusplus/LookupContext.cpp

@@ -275,7 +275,8 @@ ClassOrNamespace *LookupContext::globalNamespace() const
 }
 
 ClassOrNamespace *LookupContext::lookupType(const Name *name, Scope *scope,
-                                            ClassOrNamespace* enclosingTemplateInstantiation) const
+                                            ClassOrNamespace* enclosingTemplateInstantiation,
+                                            QSet<const Declaration *> typedefsBeingResolved) const
 {
     if (! scope) {
         return 0;
@@ -294,8 +295,14 @@ ClassOrNamespace *LookupContext::lookupType(const Name *name, Scope *scope,
                         Overview oo;
                         qDebug() << "Looks like" << oo(name) << "is a typedef for" << oo(d->type());
 #endif // DEBUG_LOOKUP
-                        if (const NamedType *namedTy = d->type()->asNamedType())
+                        if (const NamedType *namedTy = d->type()->asNamedType()) {
-                            return lookupType(namedTy->name(), scope);
+                            // Stop on recursive typedef declarations
+                            if (typedefsBeingResolved.contains(d))
+                                return 0;
+                            return lookupType(namedTy->name(), scope, 0,
+                                              QSet<const Declaration *>(typedefsBeingResolved)
+                                                << d);
+                        }
                     }
                 }
             }

src/libs/cplusplus/LookupContext.h

@@ -282,7 +282,9 @@ public:
 
     QList<LookupItem> lookup(const Name *name, Scope *scope) const;
     ClassOrNamespace *lookupType(const Name *name, Scope *scope,
-                                 ClassOrNamespace* enclosingTemplateInstantiation = 0) const;
+                                 ClassOrNamespace* enclosingTemplateInstantiation = 0,
+                                 QSet<const Declaration *> typedefsBeingResolved
+                                    = QSet<const Declaration *>()) const;
     ClassOrNamespace *lookupType(Symbol *symbol,
                                  ClassOrNamespace* enclosingTemplateInstantiation = 0) const;
     ClassOrNamespace *lookupParent(Symbol *symbol) const;

src/plugins/cpptools/cppcompletion_test.cpp

@@ -1885,3 +1885,140 @@ void CppToolsPlugin::test_completion_recursive_auto_declarations2_QTCREATORBUG95
 
     QCOMPARE(completions.size(), 0);
 }
+
+void CppToolsPlugin::test_completion_recursive_typedefs_declarations1()
+{
+    TestData data;
+    data.srcText =
+            "void f()\n"
+            "{\n"
+            "    typedef A B;\n"
+            "    typedef B A;\n"
+            "    A a;\n"
+            "    @;\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("a.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 0);
+}
+
+void CppToolsPlugin::test_completion_recursive_typedefs_declarations2()
+{
+    TestData data;
+    data.srcText =
+            "void f()\n"
+            "{\n"
+            "    typedef A C;\n"
+            "    typedef C B;\n"
+            "    typedef B A;\n"
+            "    A a;\n"
+            "    @;\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("a.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 0);
+}
+
+void CppToolsPlugin::test_completion_recursive_using_declarations1()
+{
+    TestData data;
+    data.srcText =
+            "void f()\n"
+            "{\n"
+            "    using B = A;\n"
+            "    using A = B;\n"
+            "    A a;\n"
+            "    @;\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("a.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 0);
+}
+
+void CppToolsPlugin::test_completion_recursive_using_declarations2()
+{
+    TestData data;
+    data.srcText =
+            "void f()\n"
+            "{\n"
+            "    using C = A;\n"
+            "    using B = C;\n"
+            "    using A = B;\n"
+            "    A a;\n"
+            "    @;\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("a.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 0);
+}
+
+void CppToolsPlugin::test_completion_recursive_using_typedef_declarations()
+{
+    TestData data;
+    data.srcText =
+            "void f()\n"
+            "{\n"
+            "    using B = A;\n"
+            "    typedef B A;\n"
+            "    A a;\n"
+            "    @;\n"
+            "    // padding so we get the scope right\n"
+            "}\n"
+            ;
+    setup(&data);
+
+    Utils::ChangeSet change;
+    QString txt = QLatin1String("a.");
+    change.insert(data.pos, txt);
+    QTextCursor cursor(data.doc);
+    change.apply(&cursor);
+    data.pos += txt.length();
+
+    QStringList completions = getCompletions(data);
+
+    QCOMPARE(completions.size(), 0);
+}

src/plugins/cpptools/cpptoolsplugin.h

@@ -130,6 +130,11 @@ private slots:
     void test_completion_crash_cloning_template_class_QTCREATORBUG9329();
     void test_completion_recursive_auto_declarations1_QTCREATORBUG9503();
     void test_completion_recursive_auto_declarations2_QTCREATORBUG9503();
+    void test_completion_recursive_typedefs_declarations1();
+    void test_completion_recursive_typedefs_declarations2();
+    void test_completion_recursive_using_declarations1();
+    void test_completion_recursive_using_declarations2();
+    void test_completion_recursive_using_typedef_declarations();
 
     void test_format_pointerdeclaration_in_simpledeclarations();
     void test_format_pointerdeclaration_in_simpledeclarations_data();