node.txt

Error in ./t.cr:6: instantiating 'Node#each()'

root.each { |x| puts x.data }
     ^~~~

in ./node.cr:11: undefined method 'each' for Nil

    left.each(&block) if left
         ^~~~

================================================================================

Nil trace:

  macro getter (in /opt/crystal/src/object.cr:191):4

          def left
              ^~~~

  macro getter (in /opt/crystal/src/object.cr:191):5

            @left
            ^~~~~

================================================================================

Error: instance variable '@left' of Node was not initialized in all of the 'initialize' methods, rendering it nilable.

Specifically in this one:

  ./node.cr:6

      def initialize(data)
          ^~~~~~~~~~