TreeMap#keyComparator fails if TreeMap has been created with TreeMap#ofAll

[goerge]

Following code fails

TreeMap.ofAll(Collections.singletonMap("key", "value")).keyComparator();

with

java.lang.ClassCastException: javaslang.collection.RedBlackTree$$Lambda$1/761960786 cannot be cast to javaslang.collection.TreeMap$EntryComparator

    at javaslang.collection.TreeMap.keyComparator(TreeMap.java:455)

Same error occurs when keySet() is called because keyComparator() is called inside.

[danieldietrich]

Thank you!