Autocompletion of Value based on Property for WPF-like triggers

[stevemonaco]

A WPF-like alternative for ControlTheme with triggers is being prototyped, primarily for WPF trigger support. This question primarily pertains to IntelliSense (especially in Rider) regarding detection and autocompletion of a Value based on a Property, similar to Setter. The approximate syntax looks like:

<ControlStyle TargetType="Ellipse">
  <Setter Property="Fill" Value="Black" />

  <ControlStyle.Triggers>
    <ControlTrigger Property="Ellipse.Fill" Value="Black">
      <Setter Property="Ellipse.Fill" Value="Red" />
    </ControlTrigger>
  </ControlStyle.Triggers>
</ControlStyle>

The question is regarding how much is exposed to autocompletion to aid such a setup. Question 2 being most important.

1a. Can the Ellipse type be inferred by children so that Property="Ellipse.Fill" can become Property="Fill"?
1b. Can the list of available styled properties for Property be inferred for autocompletion?
2. Can the Value be inferred on ControlTrigger from its Property and show appropriate autocomplete based on the Property being populated?

From a community question.

[maxkatz6]

XAML autocompletion (and even more - compile-time strong typing) is hardcoded to current Avalonia XAML styling syntax, with no option to extend it easily. I suppose there could be a combination of custom attributes to make it flexible.