Confusing error message for labels used before definition

[paulvanbrenk]

The following gives me an unexpected "TS1007: Jump target cannot cross function boundary error" in TS 3.3.33333

function foo() {
    for (let i = 0; i < 10; i++) {
        console.log(`${i}`);
        continue loopend;
    }

    loopend:
    console.log('end of loop');
}

Further investigation... you can jump to the start of the loop, so the error I would argue is that the error message is confusing.

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[DanielRosenwasser]

Did you try adding 3s to the version to see if the error gets better?

Seems like a reasonable request.

[DanielRosenwasser]

Here's a better message for this specific case, where the containing function of the label reference is the same as that of the labeled statement:

A label cannot be referenced prior to its declared location.

To find if it's applicable, walk up each scope until the first functionlike (isFunctionLike) or classlike (isClassLike) declaration and look for LabelledStatements in that scope.

We can also provide a related span. We already have a diagnostic for

{0} is declared here.

[paulvanbrenk]

?????? Get Outlook for Android<https://aka.ms/ghei36>

…

________________________________ From: Daniel Rosenwasser <notifications@github.com> Sent: Thursday, March 14, 2019 6:41:32 PM To: Microsoft/TypeScript Cc: Paul van Brenk; Author Subject: Re: [Microsoft/TypeScript] Confusing error message for labels used before definition (#30408) Here's a better message for this specific case. A label cannot be referenced prior to its declared location. We also should provide a related span. We already have a diagnostic for {0} is declared here. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#30408 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AFB5dwK9ovsiqwXTAzc2LlmDu5_corNoks5vWtAcgaJpZM4b1HbC>.

[DanielRosenwasser]

Actually, we already have a better message for break or continue error messages.

[paulvanbrenk]

In 3.4? Get Outlook for Android<https://aka.ms/ghei36>

…

________________________________ From: Daniel Rosenwasser <notifications@github.com> Sent: Thursday, March 14, 2019 8:13:58 PM To: Microsoft/TypeScript Cc: Paul van Brenk; Author Subject: Re: [Microsoft/TypeScript] Confusing error message for labels used before definition (#30408) Actually, we already have a better message for break or continue error messages. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#30408 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AFB5d5sWoEtjlpcsCEz1AA8hP80x1ghKks5vWuXGgaJpZM4b1HbC>.

[laurafiuza]

Hey -- is this still something that should be implemented? Happy to make changes now if no one else is already

[paulvanbrenk]

Yes, please. This is still an issue in @next