From 1ab5a6d7073ce36385b4f8ee9d97f3046f6cf201 Mon Sep 17 00:00:00 2001
From: mmporong <mmporong@gmail.com>
Date: Tue, 27 Oct 2026 16:43:32 +0900
Subject: [PATCH] Numeric#<=> returns nil unless the receiver is the argument

`Numeric#<=>` returns 0 when `other` is the receiver and nil otherwise,
as the comment above the signature says, but the return type was
`Integer`. Use `Integer?`, and add a test for both cases.
---
 core/numeric.rbs            | 2 +-
 test/stdlib/Numeric_test.rb | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/core/numeric.rbs b/core/numeric.rbs
index e8df26fe4..bc983b432 100644
--- a/core/numeric.rbs
+++ b/core/numeric.rbs
@@ -237,7 +237,7 @@ class Numeric
   #
   # No subclass in the Ruby Core or Standard Library uses this implementation.
   #
-  def <=>: (Numeric other) -> Integer
+  def <=>: (Numeric other) -> Integer?
 
   # <!--
   #   rdoc-file=numeric.c
diff --git a/test/stdlib/Numeric_test.rb b/test/stdlib/Numeric_test.rb
index cbaefa608..ad10c03c1 100644
--- a/test/stdlib/Numeric_test.rb
+++ b/test/stdlib/Numeric_test.rb
@@ -5,6 +5,12 @@ class NumericInstanceTest < Test::Unit::TestCase
 
   testing 'Numeric'
 
+  def test_op_cmp
+    numeric = Numeric.new
+    assert_send_type '(Numeric) -> 0', numeric, :<=>, numeric
+    assert_send_type '(Numeric) -> nil', numeric, :<=>, Numeric.new
+  end
+
   def test_real
     assert_send_type '() -> Integer', 1, :real
     assert_send_type '() -> Float', 1.0, :real