Iterable.forEachIndexed: The parameter list of (the action passed to) forEachIndexed should naturally extend the parameter list of forEach. Because it’s forEachIndexed rather than indexedForEach, it should be forEachIndexed { elem, idx -> ... } rather than forEachIndexed { idx, elem -> ... }. The current order is counter-intuitive.
Same for other similar methods (e.g. mapIndexed).