Different behaviors between actual compiler and baselines of class member override.

[g-plane]

Bug Report

🔎 Search Terms

class override

🕗 Version & Regression Information

• This changed between versions 4.2.0 and nightly

⏯ Playground Link

Playground link with relevant code

💻 Code

class B {
    p1: number = 1;
    p2: number = 2;
    p3: number = 3;
    p4: number = 4;
    oop: number;
    pp: number;
    op: number;
}

class D extends B{
    declare p1: number

    override declare p2: number;

    readonly override p3: number;

    override readonly p4: number;

    override static sp: number;

    override override oop: number;

    public override pp: number;
    override public op: number;

    override constructor () {
        super();
    }
}

🙁 Actual behavior

I've tried the same code in playground with nightly version and with npm install typescript@next, and there's only one compilation error occurred: 'override' modifier already seen. . Other errors, such as 'public' modifier must precede 'override' modifier., 'static' modifier cannot be used with 'override' modifier. and etc. can't be reproduced as baselines in https://github.com/microsoft/TypeScript/blob/master/tests/baselines/reference/override5.errors.txt , so I'm not sure which one is correct.

Context: we're implementing parsing override syntax in swc: swc-project/swc#1541 .

🙂 Expected behavior

Not sure. Stated as above.

[andrewbranch]

It looks like all those errors depend on --noImplicitOverride being enabled. I don’t know why that would be the case—it seems like all the grammar checking should happen regardless of the flag. Also, was it intentional that the order of modifiers between override and readonly isn’t enforced? /cc @DanielRosenwasser @Kingwl

[DanielRosenwasser]

I think override should precede readonly.

[Kingwl]

My bad. Thanks!

[g-plane]

There's another pull request which may be related to this: #43545 .