CppEditor: Let user decide whether to use "auto"

... in "Assign to Local Variable" quickfix.

Fixes: QTCREATORBUG-28099
Change-Id: I3640ef3d1e069bb2cac4d78f0ae60726b131c4fe
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/cppeditor/cppeditorconstants.h

@@ -47,6 +47,7 @@ const char QUICK_FIX_SETTING_SIGNAL_WITH_NEW_VALUE[] = "SignalWithNewValue";
 const char QUICK_FIX_SETTING_SETTER_AS_SLOT[] = "SetterAsSlot";
 const char QUICK_FIX_SETTING_SETTER_PARAMETER_NAME[] = "SetterParameterName";
 const char QUICK_FIX_SETTING_CPP_FILE_NAMESPACE_HANDLING[] = "CppFileNamespaceHandling";
+const char QUICK_FIX_SETTING_USE_AUTO[] = "UseAutoInAssignToVar";
 const char QUICK_FIX_SETTING_MEMBER_VARIABEL_NAME_TEMPLATE[] = "MemberVariableNameTemplate";
 const char QUICK_FIX_SETTING_VALUE_TYPES[] = "ValueTypes";
 const char QUICK_FIX_SETTING_RETURN_BY_CONST_REF[] = "ReturnNonValueTypesByConstRef";

src/plugins/cppeditor/cppquickfixes.cpp

@@ -1614,8 +1614,10 @@ private:
         CppRefactoringChanges refactoring(snapshot());
         CppRefactoringFilePtr currentFile = refactoring.file(filePath());
         Overview oo = CppCodeStyleSettings::currentProjectCodeStyleOverview();
+        const auto settings = CppQuickFixProjectsSettings::getQuickFixSettings(
+                    ProjectExplorer::ProjectTree::currentProject());
 
-        if (currentFile->cppDocument()->languageFeatures().cxx11Enabled)
+        if (currentFile->cppDocument()->languageFeatures().cxx11Enabled && settings->useAuto)
             return "auto " + oo.prettyName(simpleNameAST->name);
 
         TypeOfExpression typeOfExpression;
@@ -6764,7 +6766,9 @@ private:
 
     QString deduceType() const
     {
-        if (m_file->cppDocument()->languageFeatures().cxx11Enabled)
+        const auto settings = CppQuickFixProjectsSettings::getQuickFixSettings(
+                    ProjectExplorer::ProjectTree::currentProject());
+        if (m_file->cppDocument()->languageFeatures().cxx11Enabled && settings->useAuto)
             return "auto " + m_originalName;
 
         TypeOfExpression typeOfExpression;

src/plugins/cppeditor/cppquickfixsettings.cpp

@@ -75,6 +75,8 @@ void CppQuickFixSettings::loadSettingsFrom(QSettings *s)
         s->value(Constants::QUICK_FIX_SETTING_CPP_FILE_NAMESPACE_HANDLING,
                  static_cast<int>(def.cppFileNamespaceHandling))
             .toInt());
+    useAuto = s->value(Constants::QUICK_FIX_SETTING_USE_AUTO, def.useAuto).toBool();
+
     memberVariableNameTemplate = s->value(Constants::QUICK_FIX_SETTING_MEMBER_VARIABEL_NAME_TEMPLATE,
                                           def.memberVariableNameTemplate)
                                      .toString();
@@ -169,6 +171,10 @@ void CppQuickFixSettings::saveSettingsTo(QSettings *s)
                                      Constants::QUICK_FIX_SETTING_SETTER_AS_SLOT,
                                      setterAsSlot,
                                      def.setterAsSlot);
+    QtcSettings::setValueWithDefault(s,
+                                     Constants::QUICK_FIX_SETTING_USE_AUTO,
+                                     useAuto,
+                                     def.useAuto);
     QtcSettings::setValueWithDefault(s,
                                      Constants::QUICK_FIX_SETTING_VALUE_TYPES,
                                      valueTypes,

src/plugins/cppeditor/cppquickfixsettings.h

@@ -130,6 +130,7 @@ public:
     QString memberVariableNameTemplate = "m_<name>";
     QStringList valueTypes; // if contains use value. Ignores namespaces and template parameters
     bool returnByConstRef = false;
+    bool useAuto = true;
     std::vector<CustomTemplate> customTemplates;
 };
 } // namespace CppEditor

src/plugins/cppeditor/cppquickfixsettingswidget.cpp

@@ -78,6 +78,7 @@ e.g. name = "m_test_foo_":
     QObject::connect(this->ui->pushButton_removeCustomTemplate, &QPushButton::clicked, then);
     QObject::connect(this->ui->pushButton_addValueType, &QPushButton::clicked, then);
     QObject::connect(this->ui->pushButton_removeValueType, &QPushButton::clicked, then);
+    QObject::connect(this->ui->useAutoCheckBox, &QCheckBox::clicked, then);
     QObject::connect(this->ui->valueTypes, &QListWidget::itemChanged, then);
     QObject::connect(this->ui->returnByConstRefCheckBox, &QCheckBox::clicked, then);
     QObject::connect(this->ui->lineEdit_customTemplateAssignment, &QLineEdit::textEdited, then);
@@ -137,6 +138,7 @@ void CppQuickFixSettingsWidget::loadSettings(CppQuickFixSettings *settings)
     ui->lineEdit_memberVariableName->setText(settings->memberVariableNameTemplate);
     ui->checkBox_setterSlots->setChecked(settings->setterAsSlot);
     ui->checkBox_signalWithNewValue->setChecked(settings->signalWithNewValue);
+    ui->useAutoCheckBox->setChecked(settings->useAuto);
     ui->valueTypes->clear();
     for (const auto &valueType : qAsConst(settings->valueTypes)) {
         auto item = new QListWidgetItem(valueType, ui->valueTypes);
@@ -199,6 +201,7 @@ void CppQuickFixSettingsWidget::saveSettings(CppQuickFixSettings *settings)
     } else if (ui->radioButton_generateMissingNamespace->isChecked()) {
         settings->cppFileNamespaceHandling = CppQuickFixSettings::MissingNamespaceHandling::CreateMissing;
     }
+    settings->useAuto = ui->useAutoCheckBox->isChecked();
     settings->valueTypes.clear();
     for (int i = 0; i < ui->valueTypes->count(); ++i) {
         settings->valueTypes << ui->valueTypes->item(i)->text();

src/plugins/cppeditor/cppquickfixsettingswidget.ui

@@ -646,6 +646,16 @@
      </layout>
     </widget>
    </item>
+   <item>
+    <widget class="QCheckBox" name="useAutoCheckBox">
+     <property name="toolTip">
+      <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Uncheck this to make Qt Creator try to derive the type of expression in the &amp;quot;Assign to Local Variable&amp;quot; quickfix.&lt;/p&gt;&lt;p&gt;Note that this might fail for more complex types.&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
+     </property>
+     <property name="text">
+      <string>Use type &quot;auto&quot; when creating new variables</string>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="QGroupBox" name="groupBox_3">
      <property name="title">