JSDoc comment on JS class property isn't inherited when derived class also initializes it

Bug Report

When a JS class extends another, and members are overridden in the constructor, they will lose all of their documentation - even if they are compatible values.

🔎 Search Terms

jsdoc class es6 js extends

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about JS / JSDoc

⏯ Playground Link

Playground link with relevant code

Note the type info when hovering over this.a in Derived's constructor, or a in the bottom line.

💻 Code

class Base
{
    constructor()
    {
        /** I am an integer! */
        this.a = 100;
    }
}

class Derived extends Base
{
    constructor()
    {
        super();

        this.a = 50;

// hover over this.a above to see the issue
    }
}

// hover over a to see the issue as well
new Derived().a

🙁 Actual behavior

a was overridden by Derived, even though it is a type match.

🙂 Expected behavior

While I can see the usefulness here if a was a different/incompatible type entirely, I would rather an error occur on, for instance, this.a = "str"; because a is a number, not a string, and for it to inherit the JSDoc properly. It seems like this.xxx in a constructor declares a new variable, even if it inherits one.

Start with the linked TypeScript Playground and reproduce the hover behavior for this.a in Derived and new Derived().a. Trace how the JavaScript class constructors and JSDoc comment are interpreted, then verify that compatible overrides retain the documentation and incompatible assignments are diagnosed.