Widen signature for GroupedList#appendGroup.
@@ -110,7 +110,7 @@ public class GroupedList<T> implements Iterable<Collection<T>> {
// Use with caution as there are no checks in place for the integrity of the resulting object
// (no de-duping).
- public void appendGroup(Collection<T> group) {
+ public void appendGroup(Collection<? extends T> group) {
// Do a check to make sure we don't have lists here. Note that if group is empty,
// Iterables.getFirst will return null, and null is not instanceof List.
Preconditions.checkState(!(Iterables.getFirst(group, null) instanceof List),
