From 91b81730e4ff8bd4411b4367e172bd5164ef3ff0 Mon Sep 17 00:00:00 2001
From: Kazuhiro NISHIYAMA <zn@mbf.nifty.com>
Date: Wed, 14 Oct 2026 23:25:50 +0900
Subject: [PATCH] Add half: keyword to Numeric#round

Numeric#round passes all of its arguments to Float#round
(numeric.c: num_round calls flo_round(argc, argv, rb_Float(num))),
so it accepts the half: keyword as well. Use the round_mode alias
that Integer#round already uses.

The rdoc call-seq on ruby/ruby master is round(digits = 0, half: :up)
(96311d13c2), but the generated comment follows the Ruby release used
by the RBS Comments workflow, which does not have that fix yet, so the
comment is left as generated.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
---
 core/numeric.rbs            |  4 ++--
 test/stdlib/Numeric_test.rb | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/core/numeric.rbs b/core/numeric.rbs
index f81b4c79de..e8df26fe42 100644
--- a/core/numeric.rbs
+++ b/core/numeric.rbs
@@ -668,8 +668,8 @@ class Numeric
   # Numeric implements this by converting `self` to a Float and invoking
   # Float#round.
   #
-  def round: () -> Integer
-           | (Integer digits) -> Numeric
+  def round: (?half: round_mode) -> Integer
+           | (Integer digits, ?half: round_mode) -> Numeric
 
   # <!--
   #   rdoc-file=numeric.c
diff --git a/test/stdlib/Numeric_test.rb b/test/stdlib/Numeric_test.rb
index 792352e9aa..cbaefa608f 100644
--- a/test/stdlib/Numeric_test.rb
+++ b/test/stdlib/Numeric_test.rb
@@ -66,4 +66,21 @@ def test_step
     assert_send_type '(to: Rational, by: Float) { (Float) -> void } -> Rational',
                      1, :step, to: 3r, by: 0.2 do |i| break_from_block i end
    end
+
+  class NumericWithToF < Numeric
+    def to_f = 2.5
+  end
+
+  def test_round
+    receiver = NumericWithToF.new
+
+    assert_send_type '() -> Integer',
+                     receiver, :round
+    assert_send_type '(half: :even) -> Integer',
+                     receiver, :round, half: :even
+    assert_send_type '(Integer) -> Numeric',
+                     receiver, :round, 1
+    assert_send_type '(Integer, half: :down) -> Numeric',
+                     receiver, :round, 1, half: :down
+  end
 end