New isolatedDeclarations error with generic `this` parameter inference

[blickly]

Steps to reproduce

export function fromProviders<T>() {
  return {
    tearDown(this: {state: T}): void {}
  };
}

Behavior with typescript@6.0

no error, .d.ts emitted is:

export declare function fromProviders<T>(): {
    tearDown(this: {
        state: T;
    }): void;
};

link

Behavior with tsgo

error TS9008: Method must have an explicit return type annotation with --isolatedDeclarations.

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