From a628d8b01e38921059b6e46c68b4e5a777b35de9 Mon Sep 17 00:00:00 2001
From: dak2 <32436625+dak2@users.noreply.github.com>
Date: Wed, 28 Oct 2026 10:08:50 +0900
Subject: [PATCH] Fix InvalidOverloadMethodError message for singleton methods

An invalid overload such as `def self.foo: () -> void | ...` was reported
as `::Hello#foo` because the error kind was hardcoded to `:instance`.
The message pointed users to an instance method that doesn't exist.
---
 lib/rbs/definition_builder.rb       |  2 +-
 test/rbs/definition_builder_test.rb | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/lib/rbs/definition_builder.rb b/lib/rbs/definition_builder.rb
index ab0f6067d..b8ac5d405 100644
--- a/lib/rbs/definition_builder.rb
+++ b/lib/rbs/definition_builder.rb
@@ -936,7 +936,7 @@ def define_method(methods, definition, method, subst, self_type_methods, defined
           raise InvalidOverloadMethodError.new(
             type_name: definition.type_name,
             method_name: method.name,
-            kind: :instance,
+            kind: definition.class_type? ? :singleton : :instance,
             members: method.overloads
           )
         end
diff --git a/test/rbs/definition_builder_test.rb b/test/rbs/definition_builder_test.rb
index b82a2d020..b05bc7f0d 100644
--- a/test/rbs/definition_builder_test.rb
+++ b/test/rbs/definition_builder_test.rb
@@ -1727,6 +1727,26 @@ def foo: (Integer) -> String | ...
     end
   end
 
+  def test_definition_singleton_method_type_def_overload_from_super_no_super
+    SignatureManager.new do |manager|
+      manager.files.merge!(Pathname("foo.rbs") => <<-EOF)
+class Hello
+  def self.foo: (Integer) -> String | ...
+end
+      EOF
+      manager.build do |env|
+        builder = DefinitionBuilder.new(env: env)
+
+        assert_raises RBS::InvalidOverloadMethodError do
+          builder.build_singleton(type_name("::Hello"))
+        end.tap do |error|
+          assert_equal :singleton, error.kind
+          assert_include error.message, "Invalid method overloading: ::Hello.foo"
+        end
+      end
+    end
+  end
+
   def test_new_from_included_initialize
     SignatureManager.new do |manager|
       manager.files.merge!(Pathname("foo.rbs") => <<-EOF)