Issue#393

[dekajp]

Adds /* falls through */ in case statement, if break missing.

Tests not included ( working on )
#393

I am trying to build in `jake local' and 'jake tests' getting an error error TS6053: File 'Data.ts' not found. but 'jake LKG' seems to be working

[sheetalkamat]

it could be something like this
case SyntaxKind.... : return writer.write(....); and this shouldn't be fall through

[DanielRosenwasser]

First off, thanks for sending us a PR, we love contributions and interesting ideas for the compiler like this.

On one hand, this is nice because it's explicit and gives nice output. On the other, if the user didn't ask for it, I feel like this might be more trouble than it's worth, especially since I believe we'd preserve comments like /* fall through */ anyhow. Let me elaborate a bit.

@sheetalkamat gave a simple example for which this is currently misleading. But what about something marginally more complex like

switch (foo.kind) {
    case SyntaxKind.BarToken:
        if (foo.blah === "xyz") {
            break;
        }
        else {
            break;
        }
    case SyntaxKind.BazToken:
        // ...
        break;
}

So even if you also handled returns, in this case, you'd end up with something like

switch (foo.kind) {
    case 0 /* BarToken */:
        if (foo.blah === "xyz") {
            break;
        }
        else {
            break;
        }
        /* falls through */
    case 42 /* BazToken */:
        // ...
        break;
}

And so the user would be annoyed to see that /* fall through */ because it's wrong, and any reader other than the original author would be confused.

The answer might be to traverse the whole subtree with forEachChild to exhaustively check each branch, and @vladima might have recently done some work relating to this, but it might not be worth it.

[RyanCavanaugh]

I thought the idea behind #393 was that the compiler code itself should have documented fall-throughs, not that we would auto-generate a comment indicating a fall-through. I don't see any value in the latter.

[DickvdBrink]

#393 was a issue I created. What I intended was that the code should be documented that this was intended because if it wasn't intended it might cause weird side effects. So I did not intend automatic comment insertion.

[dekajp]

I am closing this PR , we can discuss this Issue on #393 .