Ignore template literal types which contain intersections in removeStringLiteralsMatchedByTemplateLiterals

[jakebailey]

For #52345

There's no reason to waste time checking template literal types which contain intersections in removeStringLiteralsMatchedByTemplateLiterals; the only thing that these can match are other template literals with intersections too.

e.g., "foo" will not match `fo${"o" & { _brand: any}}`.

Before:

After:

Maybe there's still something to do to speed up removeSubtypes for this case; will have to look harder. But, I want feedback on this PR first.

[jakebailey]

@typescript-bot pack this

[typescript-bot]

Heya @jakebailey, I've started to run the tarball bundle task on this PR at fbc0ccc. You can monitor the build here.

[typescript-bot]

Hey @jakebailey, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/150405/artifacts?artifactName=tgz&fileId=18A3F24D60E2EA4BD9511817F01BF78FD2838F7D01AC669A8E718BCBA0B9F1AF02&fileName=/typescript-5.1.0-insiders.20230321.tgz"
    }
}

and then running npm install.

---

There is also a playground for this build and an npm module you can use via "typescript": "npm:@typescript-deploys/[email protected]".;

[jakebailey]

@typescript-bot test this
@typescript-bot test top100
@typescript-bot user test this
@typescript-bot run dt

[typescript-bot]

Heya @jakebailey, I'm starting to run the diff-based user code test suite on this PR at fbc0ccc. Hold tight - I'll update this comment with the log link once the build has been queued.

Update: The results are in!

[typescript-bot]

Heya @jakebailey, I'm starting to run the diff-based top-repos suite on this PR at fbc0ccc. Hold tight - I'll update this comment with the log link once the build has been queued.

Update: The results are in!

[typescript-bot]

Heya @jakebailey, I'm starting to run the parallelized Definitely Typed test suite on this PR at fbc0ccc. Hold tight - I'll update this comment with the log link once the build has been queued.

Update: The results are in!

[typescript-bot]

Heya @jakebailey, I'm starting to run the extended test suite on this PR at fbc0ccc. Hold tight - I'll update this comment with the log link once the build has been queued.

[typescript-bot]

@jakebailey Here are the results of running the user test suite comparing main and refs/pull/53406/merge:

Everything looks good!

[typescript-bot]

@jakebailey Here are the results of running the top-repos suite comparing main and refs/pull/53406/merge:

Everything looks good!

[typescript-bot]

Hey @jakebailey, the results of running the DT tests are ready.
Everything looks the same!
You can check the log here.

[weswigham]

Eeeeeyes and no. I think I just found a bug in main thinking about this (though there was also a different bug in 5.0.2). Consider:

type MaybeCat = `c${string}` & `${string}t`;
type MaybeScats = `s${MaybeCat}s`;

declare var x: MaybeScats;

x = "scats"; // should be OK
x = "scas"; // should error

On 5.0.2, the first assignment works, but MaybeScats simplifies to sc${string}s - the t requirement is silently dropped, which isn't right - the second assignment doesn't error when it should. Right now in the nightly, we've changed that - it more correctly stays as s${MaybeCat}s now (since the intersection is left well enough alone), but we're not chopping the string up correctly to handle comparison to the nested intersection of template literals, and both assignments are errors - as-is this would exacerbate that.

While in the above example, you could see us inlining the intersection to produce sc${string}ts, a more complex intersection like a${string}b${string}c & ${string}-${string}-${string} doesn't have an obvious non-intersected form that I can see, so I don't think we can use just intersections as an indicator that we can skip comparing against it. Intersections containing object/anonymous types (or generics constrained only to such), however, would seem to be good.

[jakebailey]

Hm, so there's a bug to report on main, then, as a result of my other PR?

(At least thankfully the other PR, #53413, saves the bulk of the time on this issue, just not all.)

[weswigham]

Yes, I believe so. Though the example I gave was broken (albeit differently) in 5.0.2, too.

[jakebailey]

@typescript-bot pack this

[typescript-bot]

Heya @jakebailey, I've started to run the tarball bundle task on this PR at fa22d3a. You can monitor the build here.

[typescript-bot]

Hey @jakebailey, I've packed this into an installable tgz. You can install it for testing by referencing it in your package.json like so:

{
    "devDependencies": {
        "typescript": "https://typescript.visualstudio.com/cf7ac146-d525-443c-b23c-0d58337efebc/_apis/build/builds/150548/artifacts?artifactName=tgz&fileId=67D5594E7973670EA5E02B25D4E8AF14651FAAD590C1B4800CD726DC16E0575D02&fileName=/typescript-5.1.0-insiders.20230321.tgz"
    }
}

and then running npm install.

---

There is also a playground for this build and an npm module you can use via "typescript": "npm:@typescript-deploys/[email protected]".;