Can't import QML module from .mjs module

I have some JavaScript code in an .mjs module file that is called by C++. The C++ code also registers some types for QML to use:

    qmlRegisterUncreatableType<AiComponentData>("Isle", 1, 0, "AiComponentData", "AiComponentData should not be created in QML");

I want to use those types in my .mjs file, just like I would in a .js file:

.import Isle 1.0 as Isle

export function foo() {
    print(AiComponentData.Friendly)
}

However, I get an error:

error importing module: "Expected token `;'" "qrc:/script.mjs" "1"

I need to import the module so that I can use the enum that's registered with the AiComponentData class.