trees :: BinTreeNode :: right=
right
child for this node (or null if right no child)ENSURE: node.key < key (only if node != null)
# set `right` child for this node (or null if right no child)
# ENSURE: node.key < key (only if node != null)
fun right=(node: nullable N) do
#assert node != null implies node.key > key
right_node = node
end
lib/trees/bintree.nit:405,2--410,4