Nameclash between properties of class and subclass not found

[ThomasKiesel]

Code

"use strict";
class A
{
    constructor(public id: string)
    {}
}

class B extends A
{
    public get id() { return this._innerId;}

    private _innerId: string;
    constructor(id: string)
    {
        super(id);
        this._innerId = id;
    }
}

try
{
    new B("id2")
    alert("Erfolg")
}
catch(e)
{
    alert(e);
}

Expected behavior:

superclass A has a public property "id" which is set in the constructor.
subclass B is derived from A, but has a getter on an own property "id".

I expected that the compiler detects the name conflict between the public properties "id" in A and B respectively.

Actual behavior:
The typescript compiler generates javascript. When the code is executed, the javascript runtime throws an exception stating that the property "id" of the subclass cannot be set.

TypeError: setting getter-only property "id"
Playground Link:
https://www.typescriptlang.org/play/index.html#src=%22use%20strict%22%3B%0D%0Aclass%20A%0D%0A%7B%0D%0A%20%20%20%20constructor(public%20id%3A%20string)%0D%0A%20%20%20%20%7B%7D%0D%0A%7D%0D%0A%0D%0Aclass%20B%20extends%20A%0D%0A%7B%0D%0A%20%20%20%20public%20get%20id()%20%7B%20return%20this._innerId%3B%7D%0D%0A%0D%0A%20%20%20%20private%20_innerId%3A%20string%3B%0D%0A%20%20%20%20constructor(id%3A%20string)%0D%0A%20%20%20%20%7B%0D%0A%20%20%20%20%20%20%20%20super(id)%3B%0D%0A%20%20%20%20%20%20%20%20this._innerId%20%3D%20id%3B%0D%0A%20%20%20%20%7D%0D%0A%7D%0D%0A%0D%0Atry%0D%0A%7B%0D%0A%20%20%20%20new%20B(%22id2%22)%0D%0A%20%20%20%20alert(%22Erfolg%22)%0D%0A%7D%0D%0Acatch(e)%0D%0A%7B%0D%0A%20%20%20%20alert(e)%3B%0D%0A%7D%0D%0A

Related Issues:

[j-oliveras]

I think this works as expected.

Using a javascript equivalent (I changed alert to console.log) and running on node 8.14.1):

"use strict";
class A
{
    constructor(id)
    {
        this.id = id;
    }
}

class B extends A
{
    get id() { return this._innerId;}

    constructor(id)
    {
        super(id);
        this._innerId = id;
    }
}

try
{
    new B("id2")
    console.log("Erfolg")
}
catch(e)
{
    console.log(e);
}

I get:

TypeError: Cannot set property id of #<B> which has only a getter
    at new A (Z:\tmp\ts\index.js:6:17)
    at new B (Z:\tmp\ts\index.js:16:9)
    at Object.<anonymous> (Z:\tmp\ts\index.js:23:5)
    at Module._compile (module.js:653:30)
    at Object.Module._extensions..js (module.js:664:10)
    at Module.load (module.js:566:32)
    at tryModuleLoad (module.js:506:12)
    at Function.Module._load (module.js:498:3)
    at Function.Module.runMain (module.js:694:10)
    at startup (bootstrap_node.js:204:16)

[ThomasKiesel]

I still have this problem, I can also reproduce it with the latest compiler version (Version 3.3.0-dev.20190108) Please note: Your code sample significantly differs, the yellow parts are essential for reproduction: class A { constructor(public id) { this.id = id; } } class B extends A { get id() { return this._innerId;} private _innerId: string; constructor(id) { super(id); this._innerId = id; } } The compiler still has no errors. When I run the program, I get (with node v10.14.1) TypeError: Cannot set property id of #<B> which has only a getter at new A (C:\tfs\Extensions\DiagnosisExtensions\TypescriptBug\TypescriptBug\app.js:4:17) at new B (C:\tfs\Extensions\DiagnosisExtensions\TypescriptBug\TypescriptBug\app.js:11:9) at Object.<anonymous> (C:\tfs\Extensions\DiagnosisExtensions\TypescriptBug\TypescriptBug\app.js:16:5) at Module._compile (internal/modules/cjs/loader.js:688:30) at Object.Module._extensions..js (internal/modules/cjs/loader.js:699:10) at Module.load (internal/modules/cjs/loader.js:598:32) at tryModuleLoad (internal/modules/cjs/loader.js:537:12) at Function.Module._load (internal/modules/cjs/loader.js:529:3) at Function.Module.runMain (internal/modules/cjs/loader.js:741:12) at startup (internal/bootstrap/node.js:285:19) I hope this helps. Von: Jordi Oliveras Rovira <[email protected]> Gesendet: Dienstag, 8. Januar 2019 14:34 An: Microsoft/TypeScript <[email protected]> Cc: Kiesel, Thomas, Dr. <[email protected]>; Author <[email protected]> Betreff: Re: [Microsoft/TypeScript] Nameclash between properties of class and subclass not found (#29305) I think this works as expected. Using a javascript equivalent (I changed alert to console.log) and running on node 8.14.1): "use strict"; class A { constructor(id) { this.id = id; } } class B extends A { get id() { return this._innerId;} constructor(id) { super(id); this._innerId = id; } } try { new B("id2") console.log("Erfolg") } catch(e) { console.log(e); } I get: TypeError: Cannot set property id of #<B> which has only a getter at new A (Z:\tmp\ts\index.js:6:17) at new B (Z:\tmp\ts\index.js:16:9) at Object.<anonymous> (Z:\tmp\ts\index.js:23:5) at Module._compile (module.js:653:30) at Object.Module._extensions..js (module.js:664:10) at Module.load (module.js:566:32) at tryModuleLoad (module.js:506:12) at Function.Module._load (module.js:498:3) at Function.Module.runMain (module.js:694:10) at startup (bootstrap_node.js:204:16) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#29305 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/Ap_XAU8wqW_u1HPnthRKoR74kJcH-vQ7ks5vBJ43gaJpZM4Z1JPJ>.

[j-oliveras]

Your correct, compiler should warn that the id getter on B can conflict with id property on A.

[weswigham]

The root of the issue is that we shouldn't allow overwriting a read/write property with a writeonly one, but we don't track writeonliness, which leads to the issue.

[jakebailey]

Checking out old bugs; after #37894, all of the samples in this issue now correctly error as this mixing is now disallowed:

'id' is defined as a property in class 'A', but is overridden here in 'B' as an accessor.(2611)

So, seems like this can be closed.