[Harsh Vardhan Chauhan (1-DARK)]

Fixes #64954

In an async function, the contextual type of a returned expression is T | PromiseLike<T>. getContextualThisParameterType used that whole union as this for methods in a returned object literal. So this was {…} | PromiseLike<{…}> instead of the object type, and this satisfies { … } failed with TS1360.

This only happened when the return type came from context, such as an annotated variable or an async callback. The unannotated form infers the literal's own type, so it was already correct.

const test2: () => Promise<{ value: number; method(): void }> = async () => {
  return {
    value: 5,
    method() {
      this satisfies { value: number; method(): void }; // error TS1360 before this fix
    },
  };
};

Fix

When the containing object literal is directly returned from an async, non-generator function, drop the synthesized PromiseLike<U> from the contextual type before deriving this.

• This covers a return statement or an arrow body.
• It only removes a PromiseLike<U> whose U is also a member of the same union.
• A PromiseLike that isn't tied to a sibling member is left alone.

Verification

Case	Original	With fix
Callback: foo(async () => ({…}))	error	OK
Callback with a block body and return	error	OK
async function expression callback	error	OK
Declared async function f(): Promise<X>	error	OK
Nested literal ({ inner: {…} })	OK	OK
Array element (Promise<X[]>)	OK	OK

The full go test ./... suite passes with no baseline changes.

Notes

• A regression test (asyncReturnObjectLiteralThisType.ts, plus baselines) was written but isn't part of this PR.
• Upstream TypeScript has the same behaviour and would need a separate patch.

[Copilot]

🟡 Changes recommended

The filter mishandles returned thenables and union-valued awaited types, and regression tests are not included.

3 open issues

• Preserve PromiseLike contextual this for thenable object returns · New
• Handle flattened awaited unions when identifying synthesized Promise wrappers · New
• Add regression tests and baselines for contextual this in async returns · New

What changed in this PR

This PR addresses #64954 by adjusting contextual this typing for object-literal methods returned directly from async functions in the native TypeScript compiler.

Changes:

• Filters matching synthesized PromiseLike<T> members before deriving this.
• Adds detection for direct async returns, including parenthesized expressions and concise arrow bodies, while excluding generators.

File	Description
tsc/​internal/​checker/​checker.go	Adds async-return detection and contextual this filtering.

_{Review effort: Balanced}