diff --git a/lib/katakata_irb/type_analyzer.rb b/lib/katakata_irb/type_analyzer.rb
index 6fff938..02ef638 100644
--- a/lib/katakata_irb/type_analyzer.rb
+++ b/lib/katakata_irb/type_analyzer.rb
@@ -932,13 +932,7 @@ def assign_numbered_parameters(numbered_parameters, scope, args, _kwargs)
     return if numbered_parameters.empty?
     max_num = numbered_parameters.map { _1[1].to_i }.max
     if max_num == 1
-      if args.size == 0
-        scope['_1'] = KatakataIrb::Types::NIL
-      elsif args.size == 1
-        scope['_1'] = args.first
-      else
-        scope['_1'] = KatakataIrb::Types.array_of(*args)
-      end
+      scope['_1'] = args.first || KatakataIrb::Types::NIL
     else
       args = sized_splat(args.first, :to_ary, max_num) if args.size == 1
       numbered_parameters.each do |name|
diff --git a/test/test_type_analyze.rb b/test/test_type_analyze.rb
index 9cf374a..0edab8c 100644
--- a/test/test_type_analyze.rb
+++ b/test/test_type_analyze.rb
@@ -518,9 +518,12 @@ def test_numbered_parameter
     assert_call('loop{_1.', include: NilClass)
     assert_call('1.tap{_1.', include: Integer)
     assert_call('1.tap{_3.', include: NilClass, exclude: Integer)
-    assert_call('[:a].each_with_index{_1.', include: Array)
-    assert_call('[:a].each_with_index{_2; _1.', include: Symbol)
-    assert_call('[:a].each_with_index{_2.', include: Integer)
+    assert_call('[:a,1].tap{_1.', include: Array, exclude: [Integer, Symbol])
+    assert_call('[:a,1].tap{_2.', include: [Symbol, Integer], exclude: Array)
+    assert_call('[:a,1].tap{_2; _1.', include: [Symbol, Integer], exclude: Array)
+    assert_call('[:a].each_with_index{_1.', include: Symbol, exclude: [Integer, Array])
+    assert_call('[:a].each_with_index{_2; _1.', include: Symbol, exclude: [Integer, Array])
+    assert_call('[:a].each_with_index{_2.', include: Integer, exclude: Symbol)
   end
 
   def test_if_unless