# File lib/rspec/matchers/built_in/throw_symbol.rb, line 11
        def matches?(given_proc)
          begin
            if @expected_symbol.nil?
              given_proc.call
            else
              @caught_arg = catch :proc_did_not_throw_anything do
                catch @expected_symbol do
                  given_proc.call
                  throw :proc_did_not_throw_anything, :nothing_thrown
                end
              end

              if @caught_arg == :nothing_thrown
                @caught_arg = nil
              else
                @caught_symbol = @expected_symbol
              end
            end

            # Ruby 1.8 uses NameError with `symbol'
            # Ruby 1.9 uses ArgumentError with :symbol
          rescue NameError, ArgumentError => e
            unless e.message =~ /uncaught throw (`|\:)([a-zA-Z0-9_]*)(')?/
              other_exception = e
              raise
            end
            @caught_symbol = $2.to_sym
          rescue => other_exception
            raise
          ensure
            unless other_exception
              if @expected_symbol.nil?
                return !@caught_symbol.nil?
              else
                if @expected_arg.nil?
                  return @caught_symbol == @expected_symbol
                else
                  return (@caught_symbol == @expected_symbol) & (@caught_arg == @expected_arg)
                end
              end
            end
          end
        end