Incorrect placement of default values when function not using the this parameter satisfies an interface that DOES use the this parameter

[NkemdiAnyiam]

Search terms

this, default value, satisfies

Expected Behavior

Given:

• A function interface definition that uses the fake this parameter to set the type of this for the function (read about this TypeScript feature here: https://www.typescriptlang.org/docs/handbook/2/functions.html#declaring-this-in-a-function)
• A function—with parameters that have default values—that satisfies the interface but does not explicitly include this in its parameter list

Example code for the above:

type Square = {
  color: 'red' | 'blue' | 'green';
};

type TAnimator = {
  (this: Square, numSpins: number, direction: 'clockwise' | 'counterclockwise'): string;
}

export const animator = function(numSpins: number = 2, direction: 'clockwise' | 'counterclockwise' = 'counterclockwise') {
  console.log(this.color, numSpins, direction);
  return 'Hello World';
} satisfies TAnimator;

animator.call({color: 'blue'}, 77);

The rendered documentation for the function should display the default values with the correct parameters like this (note that this image was produced by modifying my code to mimic the desired output):

Actual Behavior

The rendered documentation offsets the default values, starting by assigning the first default value to this:

Steps to reproduce the bug

Use the provided example code and generate the output. The typedoc.json configuration makes zero difference.

Environment

• Typedoc version: 0.26.6
• TypeScript version: 5.5.3
• Node.js version: 20.16.0
• OS: Windows 11

[Gerrit0]

Wow, that's a weird one... not entirely surprising as I had to do unfortunate hackery to make this parameters show up at all...