Functions defined as methods fail type inferrence when they have arguments

[thennothinghappened]

Below is an example of this.

Interestingly, this doesn't happen when defining as a regular function, as in the second example, but does when assigned as a method in a constructor.

Also of note, removing the explicit type annotations it now believes it returns nothing:

Removing the argument (or its type annotation) also fixes it, but it refuses to acknowledge the return type still:

Finally, using JSDoc comments seem to always work: