Fixed signature caching issue caused by reentrant signature checking

[Mateusz Burzyński (Andarist)]

fixes #63949 by porting #60208 (that's basically put in the first commit in this PR).

This is basically the same as #64014 but it comes with an extra commit that doesn't regress this case:

declare const example: (f: (a: string) => number) => string;

const f = (a: string) => g();

const g = () => {
    return example(f);
};

The above should error but by porting #60208 alone, it stops doing that.

In fact, the second commit is enough to fix #63949 , the porting commit is not strictly needed for this - but I decided to keep it here as part of the Corsa-Strada alignment efforts

[Mateusz Burzyński (Andarist)]

In here, I just make sure the cached signatures stay the same regardless of the order of the LSP requests

[Copilot]

Pull request overview

Prevents reentrant signature resolution from using a function’s inferred return type as contextual evidence for its own body.

Changes:

• Adds the self-signature guard in contextual return-type resolution.
• Adds compiler and Fourslash regression coverage.
• Updates affected type, symbol, and diagnostic baselines.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tsc/internal/checker/checker.go	Excludes a function’s own signature from contextual return typing.
tsc/internal/fourslash/tests/quickInfoGenericDefaultInReentrantCallResolution_test.go	Tests stable diagnostics and quick info across request orders.
tsc/testdata/tests/cases/compiler/genericDefaultInReentrantCallResolution.ts	Reproduces issue #63949.
tsc/testdata/tests/cases/compiler/reentrantCallDoesNotReuseInapplicableCachedSignature.ts	Covers the related invalid-call regression.
tsc/testdata/baselines/reference/compiler/genericDefaultInReentrantCallResolution.types	Records corrected inferred types.
tsc/testdata/baselines/reference/compiler/genericDefaultInReentrantCallResolution.symbols	Records symbols for the regression case.
tsc/testdata/baselines/reference/compiler/reentrantCallDoesNotReuseInapplicableCachedSignature.types	Records expected types for the error case.
tsc/testdata/baselines/reference/compiler/reentrantCallDoesNotReuseInapplicableCachedSignature.symbols	Records expected symbols for the error case.
tsc/testdata/baselines/reference/compiler/reentrantCallDoesNotReuseInapplicableCachedSignature.errors.txt	Verifies the expected assignability diagnostic.
tsc/testdata/baselines/reference/conformance/neverReturningFunctions1.types	Updates affected literal widening.
tsc/testdata/baselines/reference/conformance/intraExpressionInferencesJsx.types	Updates affected JSX inference baselines.

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[Mateusz Burzyński (Andarist)]

I think those are correct, the inferred signature here includes boolean and then that object became checked with that as its contextual part so a true literal became here contextually-typed by a boolean and that makes it to retain the true type (instead of widening to boolean)