CS0518 when using "record struct"

internal readonly record struct NavRowLayout(string RowId, string Label, string Icon, float YMin, float YMax);

When using the above line alloy spits out this error:

[Alloy] ERROR: [build] plugins/GamePanel: Ui/Nav.cs:18:53 — CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
[Alloy] ERROR: [build] plugins/GamePanel: Ui/Nav.cs:18:67 — CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
[Alloy] ERROR: [build] plugins/GamePanel: Ui/Nav.cs:18:81 — CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
[Alloy] ERROR: [build] plugins/GamePanel: Ui/Nav.cs:18:93 — CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
[Alloy] ERROR: [build] plugins/GamePanel: Ui/Nav.cs:18:105 — CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported

If this is just not a supported feature that is okay, just wanted to report it so maybe a more clear message can be given. Below is the change I made to avoid this:
 

internal readonly struct NavRowLayout
{
    public readonly string RowId;
    public readonly string Label;
    public readonly string Icon;
    public readonly float YMin;
    public readonly float YMax;

    public NavRowLayout(string rowId, string label, string icon, float yMin, float yMax)
    {
        RowId = rowId;
        Label = label;
        Icon = icon;
        YMin = yMin;
        YMax = yMax;
    }
}