[Nate (servusdei2018)]

When an async arrow function has a contextual return type, the object literal it returns is contextually typed as T | PromiseLike<T>. That union was then being used as this inside the literal’s methods, which is wrong, since this is the literal itself. This change strips the promise-like members from the union before typing this. If nothing is left after that, it falls back to the literal’s own type.

const f: () => Promise<{ value: number; method(): void }> = async () => {
  return {
    value: 5,
    method() {
      // was: this: { value: number; method(): void } | PromiseLike<...>
      // now: this: { value: number; method(): void }
      this;
    },
  };
};

Fixes #64954

[Copilot]

🟡 Changes recommended

The unconditional filter also removes legitimate thenable contextual types outside async returns, causing missing-property errors in previously valid code.

1 open issue

• Restrict thenable filtering to synthetic async-return contexts · New

What changed in this PR

Addresses #64954 by excluding promise-like contextual types from this in object literal methods, targeting objects returned from async functions.

Changes:

• Filters promise-like contextual types, falling back to the literal’s own type when none remain.
• Adds an async-return regression test with type, symbol, and JavaScript baselines.

File	Description
tsc/​testdata/​tests/​cases/​compiler/​thisInObjectLiteralMethodAsyncReturn.ts	Tests inferred and annotated async returns.
tsc/​testdata/​baselines/​reference/​compiler/​thisInObjectLiteralMethodAsyncReturn.types	Records expected contextual this types.
tsc/​testdata/​baselines/​reference/​compiler/​thisInObjectLiteralMethodAsyncReturn.symbols	Records expected symbol bindings.
tsc/​testdata/​baselines/​reference/​compiler/​thisInObjectLiteralMethodAsyncReturn.js	Records emitted JavaScript.
tsc/​internal/​checker/​checker.go	Filters promise-like types when determining contextual this.

_{Review effort: Balanced}