TH\Maybe\Result\flatten

Converts from Result<Result<T, E>, E> to Result<T, E>.

Examples

$x = Result\ok(3);
self::assertSame(Result\flatten(Result\ok($x)), $x);

$x = Result\err("deity");
self::assertSame(Result\flatten($y = Result\ok($x)), $x);

self::assertEq(Result\flatten($x), Result\err("deity"));