class RSpec::Matchers::BuiltIn::Compound::NestedEvaluator

def inner_matcher_block(outer_args)

the args on to the `expect` block.
When such a matcher is used as the outer matcher, we need to forward the
Some block matchers (such as `yield_xyz`) pass args to the `expect` block. 
def inner_matcher_block(outer_args)
  return @actual if outer_args.empty?
  Proc.new do |*inner_args|
    unless inner_args.empty?
      raise ArgumentError, "(#{@matcher_1.description}) and " \
        "(#{@matcher_2.description}) cannot be combined in a compound expectation " \
        "since both matchers pass arguments to the block."
    end
    @actual.call(*outer_args)
  end
end