/**
 * This type checks that the type `true` is passed to it.
 */
export type Expect<T extends true> = T;
/**
 * Returns `true` if types are exactly equal and `false` otherwise.
 * IsEqual<{foo: string}, {foo: string}> = true.
 * IsEqual<{readonly foo: string}, {foo: string}> = false.
 */
export type IsEqual<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2 ? true : false;
/**
 * Returns `true` if key is readonly in object and `false` otherwise.
 * IsReadonlyKey<{readonly foo?: 2}, 'foo'> = true.
 * IsReadonlyKey<{foo: ''}, 'foo'> = false.
 */
export type IsReadonlyKey<SomeObject extends object, Key extends keyof SomeObject> = IsEqual<Readonly<Pick<SomeObject, Key>>, Pick<SomeObject, Key>>;