Fix ArgumentError in aliased macro

Closes: https://github.com/ruby/ruby/pull/2221

lib/reline/line_editor.rb

@@ -641,6 +641,10 @@ class Reline::LineEditor
     end
   end
 
+  private def argumentable?(method_obj)
+    method_obj and method_obj.parameters.length != 1
+  end
+
   private def process_key(key, method_symbol)
     if method_symbol and respond_to?(method_symbol, true)
       method_obj = method(method_symbol)
@@ -648,14 +652,20 @@ class Reline::LineEditor
       method_obj = nil
     end
     if method_symbol and key.is_a?(Symbol)
-      method_obj&.(key, arg: @vi_arg)
+      if @vi_arg and argumentable?(method_obj)
+        run_for_operators(key, method_symbol) do
+          method_obj.(key, arg: @vi_arg)
+        end
+      else
+        method_obj&.(key)
+      end
       @kill_ring.process
       @vi_arg = nil
     elsif @vi_arg
       if key.chr =~ /[0-9]/
         ed_argument_digit(key)
       else
-        if ARGUMENTABLE.include?(method_symbol) and method_obj
+        if argumentable?(method_obj)
           run_for_operators(key, method_symbol) do
             method_obj.(key, arg: @vi_arg)
           end

test/reline/test_macro.rb

@@ -0,0 +1,34 @@
+require_relative 'helper'
+
+class Reline::MacroTest < Reline::TestCase
+  def setup
+    @config = Reline::Config.new
+    @line_editor = Reline::LineEditor.new(@config)
+    @line_editor.instance_variable_set(:@screen_size, [24, 80])
+    @line_editor.output = File.open(IO::NULL, "w")
+  end
+
+  def input_key(char, combined_char = char, with_meta = false)
+    @line_editor.input_key(Reline::Key.new(char, combined_char, with_meta))
+  end
+
+  def input(str)
+    str.each_byte {|c| input_key(c)}
+  end
+
+  def test_simple_input
+    input('abc')
+    assert_equal 'abc', @line_editor.line
+  end
+
+  def test_alias
+    class << @line_editor
+      alias delete_char ed_delete_prev_char
+    end
+    input('abc')
+    assert_nothing_raised(ArgumentError) {
+      input_key(:delete_char)
+    }
+    assert_equal 'ab', @line_editor.line
+  end
+end