Cannot access protected field but private field inside nested class

🔎 Search Terms

private, protected

🕗 Version & Regression Information

Version 5.6.2

⏯ Playground Link

https://www.typescriptlang.org/play/?#code/KYDwDg9gTgLgBAYwDYEMDOa4DEITgbwChC5S4woIZgFqATOGACwEs0BJNABUutuAYBeOAEYA3CTIUWANxTVGrDtyiz5wOMPHEycAEYooACgCUALhx4iu3QggA7NPGbzNithJtlJXqMBgArlD2cPbAAO6IqBhwoNT2dJiWBDpeNmgQALb+rPYA5qYpacVwfoHBivIAdMxsnDxqCgDUlTA1SvW8NPSeJaQAvj42g7qD-UA

💻 Code

export class Foo {

    protected thisIsProtected = 1;
    private thisIsPrivate = 1;

    bar():Foo {
        const that = this;
        
        return new class extends Foo {

            something() {
                return that.thisIsPrivate + that.thisIsProtected;
            }
        }
    }
}

🙁 Actual behavior

I get a compile error for that.thisIsProtected, but not for that.thisIsPrivate

🙂 Expected behavior

I can access the protected field, like the private

Additional information about the issue

No response

Start with the linked TypeScript Playground reproduction and compare how the checker handles protected and private access through the nested anonymous class. Trace the access check for that.thisIsProtected versus that.thisIsPrivate, then verify that the protected access behaves as expected without regressing the private case.