Make ModuleResolutionKind.Node10 change backward-compatible

[andrewbranch]

Fixes #53131

[jakebailey]

That CI result is... weird. is this somehow non-deterministic? Maybe we have to make NodeJs defined as NodeJs = Node10?

[andrewbranch]

No, I just forgot to run tests with type checking after I swapped the order.

[andrewbranch]

@typescript-bot cherry-pick to release-5.0

[typescript-bot]

Heya @andrewbranch, I've started to run the task to cherry-pick this into release-5.0 on this PR at f02c5ea. You can monitor the build here.

[jakebailey]

Oh, phew.

This reminds me that Debug.formatEnum always picks the first name (so you can deprecate via an assignment, e.g. SyntaxKind.JSDoc and SyntaxKind.JSDocComment), so this PR would actually debug print as the deprecated name (as that's first), but then the enum at runtime is the opposite. Unfortunate.

[typescript-bot]

Hey @andrewbranch, I've opened #53143 for you.

[andrewbranch]

The order has to be this way to make the enum reverse mapping point to the non-deprecated name, which appears in tsc --traceResolution. Honestly, formatEnum should probably do that too. Deprecated enum members that share a value with a non-deprecated member should always come first if reverse mapping ever matters.

[jakebailey]

Yeah, I agree. Unfortunately in SyntaxKind's case, we must define old names in terms of new names (or vice versa) since the overall values are not stable (compared to this PR where we hardcoded "2").

But since it's vice versa, I can just send a PR that flips them around and it'll work.

[jakebailey]

Although, I think the reason to pick the first one is due to cases like:

enum NodeFlags {
    Number = 1 << 1,
    String = 1 << 2,
    Something = Number | String, // What if String is removed?
}

[andrewbranch]

I’m not sure why you can’t forward reference since it gets inlined anyway https://www.typescriptlang.org/play?#code/KYOwrgtgBAolDeAoKKoEEoF4oEYA0yqAQluogL5A

[jakebailey]

If you forward reference, you get an error:

A member initializer in a enum declaration cannot reference members declared after it, including members defined in other enums. ts(2651)

Anyway, not super relevant to this PR besides formatEnum doing the wrong thing, but, I don't really think it's a big deal.

[andrewbranch]

Yeah, I meant I’m not sure why we issue that error in the first place.

[jakebailey]

Yeah, though if you add a forward reference, the value it emits is... not right.

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