class RSpec::Core::SharedExampleGroup::Collection

def [](key)
  fetch_examples(key) || warn_deprecation_and_fetch_anyway(key)
end

def fetch_anyway(key)
  @examples.values.inject({}, &:merge)[key]
end

def fetch_examples(key)
  @examples[source_for key][key]
end

def initialize(sources, examples)
  @sources, @examples = sources, examples
end

def source_for(key)
  @sources.reverse.find { |source| @examples[source].has_key? key }
end

def warn_deprecation_and_fetch_anyway(key)
  if (example = fetch_anyway key)
    backtrace_line = caller.find { |line| !line.include?('lib/rspec/core') }
    RSpec.warn_deprecation <<-WARNING.gsub(/^ /, '')
      Accessing shared_examples defined across contexts is deprecated.
      Please declare shared_examples within a shared context, or at the top level.
      This message was generated at: #{backtrace_line}
    WARNING
    example
  end
end