Getter (with setter) that doesn't return on all paths doesn't have a correct error span

[stevenfowler16]

TypeScript Version: 3.5.2

Search Terms:
ts2366
Code

export default class InputRadioButtonsWebComponent extends HTMLElement {
    private MapRadioButton: Map < HTMLInputElement, HTMLButtonElement > = new Map < HTMLInputElement, HTMLButtonElement > ();

    get Value() {
        for (const entry of this.MapRadioButton.entries()) {
            if (entry[0].checked === true) {
                return entry[0].value;
            }
        }

    }

    set Value(value: string) {
        if (value !== null) {
            this.setAttribute('value', value.toString());
        }
    }

}


let customElements = window.customElements;
if (customElements.get('radio-buttons') === undefined) {
    customElements.define('radio-buttons', InputRadioButtonsWebComponent);
}

Expected behavior:
Throw the error during the build process with the file and line specified.

Actual behavior:
Function lacks ending return statement and return type does not include undefined is thrown at the bottom of the file. The build provides zero idea as to where the error could have come from.
Looks like ESLint only runs on open files which was one reason why finding the file was so difficult.
Playground Link:
https://www.typescriptlang.org/play/#code/FAUwHgDg9gTgLgAgCYgGYEMCuAbRBjbdAZyIQEkA7CTOAJXSQEsoAhGuKCogdRACMAwlAC20CiAqJwcCUlIAJACoBZADIBRbCGETEAb2AIjCCDEYA3dDITL0Eek1btOALht2APErWVqcTdq6ADQI3qpscBwUATqSAHwIALwI4gDu7hBeKqq+NDHBodkRUfnxABQAlADchsa1RgDmIIgAaujYmCCVCAYAkL2osAhleJxEUpIwAJ4IUKgIcAAWjEQAdLb2DMzFnKu6ZiBElRU9wP29jPNl+1MA2gAMALqreIsgeADWIEhJiclwME6Jz65xgzUwMAoCBuD2elg6IBqxmRKIAvuczr1UWdsWciM0EG0EWV4Z03OMzBQGsDMZdhqSQAgAIR-FI4bA085LFarfFwACCkTMfBoXQA5AyxSEGasOABlAGMKnHGr9bFY3rAYC44BafCYcYiUpwUjJVJKpBQVIvA0cYTGog1OkjW1GrSxE2rJpwMpimBbKAAWhFkTGYpOf2SmAoKFQSu+nLwrvt7t0a1j8d9-scwecXCl5CoNAc2zzPH4QlEnF01W1wCAA
Related Issues:
91

[RyanCavanaugh]

Shorter version

class A {
	get Value() {
		if (Math.random() > 0.5) {
  		return 0
		}
	}

	set Value(value: number) {
	}
}

[MartinJohns]

If a method returns nothing, then it implicitly returns undefined. So the correct type would be number | undefined.

If you have the compiler option noImplicitReturns enabled, then you additionally need to explicitly return undefined.

[DanielRosenwasser]

Thanks @a-tarasyuk!