Double Emit of Contructor when using Getter Decorators

[Matchlighter]

Bug Report

With the implementation of Stage 3 Decorators in TS 5, using a getter decorator can result in the content of the constructor being duplicated in the emitted code, for example:

            constructor() {
                this.computedVal;
                console.log("As will this");
                __runInitializers(this, _instanceExtraInitializers);
                this.computedVal;
                console.log("As will this");
            }

🔎 Search Terms

Constructor duplicate decorators getter

🕗 Version & Regression Information

Started seeing this when I updated a library from TS 5.0-beta to TS 5.0.2.

This changed between versions 5.0-beta and 5.0.2. Not applicable to prior versions.

⏯ Playground Link

Playground link with relevant code

💻 Code

function computed(target, ctx: ClassGetterDecoratorContext) {
    ctx.addInitializer(function () {
        console.log("INIT")
    })
    return target
}

class Bla {
    // Things seem to work as expected if a field or accessor is also defined,
    //   but additional getters/setters or methods continue to see the double emission
    // name: string = ""

    @computed
    get computedVal() {
        console.log("This will print twice")
        return 3
    }

    constructor() {
        this.computedVal
        console.log("As will this")
    }
}

new Bla()

🙁 Actual behavior

Constructor logic is duplicated:

            constructor() {
                this.computedVal;
                console.log("As will this");
                __runInitializers(this, _instanceExtraInitializers);
                this.computedVal;
                console.log("As will this");
            }

🙂 Expected behavior

Constructor logic should not be duplicated:

            constructor() {
                __runInitializers(this, _instanceExtraInitializers);
                this.computedVal;
                console.log("As will this");
            }

[rbuckton]

The underlying issue is that the logic to inject __runInitializers() into a constructor incorrectly called addRange/visitNodes twice when a super() wasn't present. This only occurred for getters, setters, and methods because __runInitializers() is injected into the constructor when there are no fields present, but is injected into the first field initializer when fields are present.