Experiment: Remove lower priority from contextual signature instantiation return type inference

[andrewbranch]

No description provided.

[andrewbranch]

@typescript-bot test top200

[typescript-bot]

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
test top200	✅ Started

[andrewbranch]

@typescript-bot pack this

[typescript-bot]

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
pack this	✅ Started	✅ Results

[typescript-bot]

Hey @andrewbranch, 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/161473/artifacts?artifactName=tgz&fileId=C723169543A40FB90A0107AC550ACF4D6B41276B124BA86254E134BF631E468F02&fileName=/typescript-5.5.0-insiders.20240425.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/pr-build@5.5.0-pr-58321-4".;

[andrewbranch]

@typescript-bot test top200
@typescript-bot pack this

[typescript-bot]

Starting jobs; this comment will be updated as builds start and complete.

Command	Status	Results
test top200	✅ Started	👀 Results
pack this	✅ Started	✅ Results

[typescript-bot]

Hey @andrewbranch, 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/161474/artifacts?artifactName=tgz&fileId=0D50580727580C2B54AFD5A51B91EA4A6271481DD62F02A2B1CEE60EA09EF4C902&fileName=/typescript-5.5.0-insiders.20240425.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/pr-build@5.5.0-pr-58321-7".;

[gabritto]

I wrote this test to exercise a very specific inference code path in the PR that introduced it, so it's not grounded in a real world scenario, but I don't think the new error is worse? Maybe the connection between the error and the actual code is more surprising now just because we end up inferring T = { [x: string]: number } instead of T = U.

Maybe that's a separate problem with signature comparison: it's not immediately clear to users that we've done inference in order to compare two signatures, and it's not immediately clear what the result of that inference was.

[typescript-bot]

@andrewbranch Here are the results of running the top 400 repos comparing main and refs/pull/58321/merge:

Something interesting changed - please have a look.

Details

gcanti/fp-ts

4 of 5 projects failed to build with the old tsc and were ignored

tsconfig.build-es6.json

• error TS2345: Argument of type '<A>(a: A) => Either<E, NonNullable<A>>' is not assignable to parameter of type '(b: B | null | undefined) => Either<E, B & {}>'.
  • src/Either.ts#L1427
• error TS2345: Argument of type '<A>(a: A) => HKT<F, Either<E, NonNullable<A>>>' is not assignable to parameter of type '(b: B | null | undefined) => HKT<F, Either<E, B & {}>>'.
  • src/EitherT.ts#L173
• error TS2322: Type '<A extends readonly unknown[]>(...eqs: { [K in keyof A]: Eq<A[K]>; }) => Eq<Readonly<A>>' is not assignable to type '<T extends readonly Eq<any>[]>(...eqs: T) => Eq<{ [K in keyof T]: T[K] extends Eq<infer A> ? A : never; }>'.
  • src/Eq.ts#L201
• error TS2345: Argument of type '<A>(a: A) => Option<NonNullable<A>>' is not assignable to parameter of type '(b: B | null | undefined) => Option<B & {}>'.
  • src/Option.ts#L1070
• error TS2345: Argument of type '<A>(a: A) => HKT<F, Option<NonNullable<A>>>' is not assignable to parameter of type '(b: B | null | undefined) => HKT<F, Option<B & {}>>'.
  • src/OptionT.ts#L136
• error TS2322: Type '<A extends readonly unknown[]>(...ords: { [K in keyof A]: Ord<A[K]>; }) => Ord<Readonly<A>>' is not assignable to type '<T extends readonly Ord<any>[]>(...ords: T) => Ord<{ [K in keyof T]: T[K] extends Ord<infer A> ? A : never; }>'.
  • src/Ord.ts#L420
• error TS2322: Type '<A extends readonly unknown[]>(...shows: { [K in keyof A]: Show<A[K]>; }) => Show<Readonly<A>>' is not assignable to type '<T extends readonly Show<any>[]>(...shows: T) => Show<{ [K in keyof T]: T[K] extends Show<infer A> ? A : never; }>'.
  • src/Show.ts#L69