Compiler panic compiling `init` callback from a component inlined into a repeater

I randomly found a bug in the compiler that panics with the following message:

i-slint-compiler-1.5.1/llr/lower_expression.rs:35:34:
  called `Option::unwrap()` on a `None` value

It appears under some weird circumstances. I was able to reproduce it like this:

Declare a new component, let it inherit from e.g. a Rectangle
Inside the declaration, define an animation for any visual property
Also inside the declaration, define an init method and let it change any property of the component
Declare a window, in which you place the your component using a for loop

For example:

component MyComponent inherits Rectangle {
  animate background {}
  init => {
    self.background = #000;
  }
}

export component MyWindow inherits Window {
  for _ in [1, 2, 3]: MyComponent {}
}

That bug also appears in SlintPad, it freezes the preview window and prints a similar error message in the JS console.

slint-ui / slint

Compiler panic compiling `init` callback from a component inlined into a repeater #5146