class Hash
  def find_recursive(&block)
    result = catch(:found) do
      find do |key, value|
        result = value.find_recursive(&block) rescue yield(key, value)
        throw(:found, result) if result
      end
    end
    result
  end
end

class Module
  def constant(const)
    const = const.to_s.dup
    base = const.sub!(/^::/, '') ? Object : ( self.kind_of?(Module) ? self : self.class )
    const.split(/::/).inject(base){ |mod, name| mod.const_get(name) }
  end

  def recursive_constants done = []
    tree = (constants - done).sort.inject({}) do |tree, const|
      mod = const_get(const)
      consts = mod.recursive_constants(constants + done) rescue mod
      tree[const] = consts
      tree
    end
    tree.empty? ? self.name : tree
  end

  def recursive_const_search(name)
    result = recursive_constants.find_recursive do |key, value|
      value if key == name.to_s
    end
    constant(result) rescue nil
  end
end

module Foo
  module Bar
    class FooBar
      def test
        "passed!"
      end
    end
  end
end

result = Module.recursive_const_search(:FooBar).new.test rescue "not passed!"
puts result