Intersection with mapped type broken in function with generic in 4.1.2 #41655

import { UpdateQuery } from 'mongodb';

interface Foo {
  foo: string;
}

function testWithGeneric<TSchema>(): UpdateQuery<TSchema> {
  const update: UpdateQuery<TSchema> = {};

  if (Math.random() < 0.5) {
    const key: string = 'newKey';
    const value: any = true;

    update.$set = {
      ...(update.$set || {}),
      [key]: value
    };
  }

  return update;
}

function testWithoutGeneric(): UpdateQuery<Foo> {
  const update: UpdateQuery<Foo> = {};

  if (Math.random() < 0.5) {
    const key: string = 'newKey';
    const value: any = true;

    update.$set = {
      ...(update.$set || {}),
      [key]: value
    };
  }

  return update;
}

type DotAndArrayNotation<AssignableType> = {
    readonly [key: string]: AssignableType;
};

type ReadonlyPartial<TSchema> = {
    readonly [key in keyof TSchema]?: TSchema[key];
};

export type MatchKeysAndValues<TSchema> = ReadonlyPartial<TSchema> & DotAndArrayNotation<any>;

export type UpdateQuery<TSchema> = {
    $set?: MatchKeysAndValues<TSchema>;
    // other fields here don't matter
};