Turn on QML Language Server

Since Qt 6.4, QML Language Server offers code completion and issues warnings for QML. To use it, go to Preferences > Qt Quick > QML/JS Editing and select Enable QML Language Server.

By default, enabling QML Language Server will only enable warning messages and code completion, while advanced features such as renaming and finding usages will be handled by the embedded code model. To disable the embedded code model and use QML Language Server for everything, select Use QML Language Server advanced features.

Also, Qt Creator tries to use QML Language Server shipped with the Qt version in your current kit. To override that behavior and always use QML Language Server of the highest registered Qt version, select Use QML Language Server from latest Qt version.

{QML/JS Editing preferences}

When using qmlls from Qt 6.7 or later, set QT_QML_GENERATE_QMLLS_INI to ON in Projects > Build Settings > Initial Configuration.

See also How To: Manage Language Servers, Enabling and Disabling Messages, CMake Build Configuration, and Language Servers.