enums-are-not-types.qdoc

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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
\page qmllint-warnings-and-errors-enums-are-not-types.html
\ingroup qmllint-warnings-and-errors
 
\title Enums are not types
\brief [enums-are-not-types] Enum names used as type annotations.
 
\qmllintwarningcategory enums-are-not-types
 
\section1 QML enumerations are not types
 
\section2 What happened?
You used an enum name inside a type annotation.
 
\section2 Why is that bad?
An enum name is not a type and therefore can't be used in a type annotation. QML tooling is
not able to use the type annotation: the \l{Qt Quick Compiler}{compiler} can't compile this
method to C++ and \l{qmllint} as well as \l{\QMLLS} can't analyze this method.
 
\section2 Example
\qml
// Main.qml
import QtQuick
 
Item {
    enum HelloWorld { Hello, World }
    function f(e: Main.HelloWorld): bool {
        return e == World
    }
}
\endqml
To fix this warning, replace the enum name in the type annotation with the underlying type,
like \c{int} if the underlying type needs at most 32 bit, or otherwise \c{double}, for example.
 
\qml
import QtQuick
 
Item {
    enum HelloWorld { Hello, World }
    function f(e: int): bool {
        return e === World
    }
}
\endqml
*/