USe QStringView here

src/private/protocolgen/cppgenerator.cpp

@@ -801,7 +801,13 @@ void CppGenerator::writeImplPropertyDependencies(const PropertyNode *node)
                 }
             }
             if (!values.isEmpty()) {
-                mImpl << "    m" << key[0].toUpper() << key.midRef(1) << " |= " << enumType << "(" << values.join(QLatin1String(" | ")) << ");\n";
+                mImpl << "    m" << key[0].toUpper()
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+                      << QStringView(key).mid(1)
+#else
+                      << key.midRef(1)
+#endif
+                      << " |= " << enumType << "(" << values.join(QLatin1String(" | ")) << ");\n";
                 values.clear();
             }
         }
@@ -809,7 +815,13 @@ void CppGenerator::writeImplPropertyDependencies(const PropertyNode *node)
     }
 
     if (!values.isEmpty()) {
-        mImpl << "    m" << key[0].toUpper() << key.midRef(1) << " |= " << enumType << "(" << values.join(QLatin1String(" | ")) << ");\n";
+        mImpl << "    m" << key[0].toUpper()
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+              << QStringView(key).mid(1)
+#else
+              << key.midRef(1)
+#endif
+              << " |= " << enumType << "(" << values.join(QLatin1String(" | ")) << ");\n";
     }
 }
 

src/private/protocolgen/nodetree.cpp

@@ -290,10 +290,20 @@ PropertyNode::Setter *PropertyNode::setter() const
 
 QString PropertyNode::mVariableName() const
 {
-    return QStringLiteral("m") + mName[0].toUpper() + mName.midRef(1);
+    return QStringLiteral("m") + mName[0].toUpper() +
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+        QStringView(mName).mid(1);
+#else
+        mName.midRef(1);
+#endif
 }
 
 QString PropertyNode::setterName() const
 {
-    return QStringLiteral("set") + mName[0].toUpper() + mName.midRef(1);
+    return QStringLiteral("set") + mName[0].toUpper() +
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+        QStringView(mName).mid(1);
+#else
+        mName.midRef(1);
+#endif
 }

src/private/protocolgen/nodetree.h

@@ -89,7 +89,12 @@ public:
 
         QString mVariableName() const
         {
-            return QStringLiteral("m") + name[0].toUpper() + name.midRef(1);
+            return QStringLiteral("m") + name[0].toUpper() +
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+                QStringView(name).mid(1);
+#else
+                name.midRef(1);
+#endif
         }
     };
 

src/server/storage/dbconfigpostgresql.cpp

@@ -77,11 +77,19 @@ private:
             return {};
         }
         bool ok = false;
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+        const auto major = QStringView(name).left(dotIdx).toInt(&ok);
+#else
         const auto major = name.leftRef(dotIdx).toInt(&ok);
+#endif
         if (!ok) {
             return {};
         }
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 2)
+        const auto minor = QStringView(name).mid(dotIdx + 1).toInt(&ok);
+#else
         const auto minor = name.midRef(dotIdx + 1).toInt(&ok);
+#endif
         if (!ok) {
             return {};
         }