Fix InvalidOverloadMethodError on overloading extended method

lib/rbs/definition_builder.rb

@@ -239,14 +239,6 @@ def build_singleton0(type_name)
             definition.class_variables.merge!(defn.class_variables)
           end
 
-          all_interfaces = one_ancestors.each_extended_interface.flat_map do |interface|
-            other_interfaces = ancestor_builder.interface_ancestors(interface.name).ancestors #: Array[Definition::Ancestor::Instance]
-            other_interfaces = other_interfaces.select {|ancestor| ancestor.source }
-            [interface, *other_interfaces]
-          end
-          interface_methods = interface_methods(all_interfaces)
-          import_methods(definition, type_name, methods, interface_methods, Substitution.new)
-
           one_ancestors.each_extended_module do |mod|
             mod.args.each do |arg|
               validate_type_presence(arg)
@@ -256,7 +248,12 @@ def build_singleton0(type_name)
             define_instance(definition, mod.name, subst)
           end
 
-          interface_methods = interface_methods(one_ancestors.each_extended_interface.to_a)
+          all_interfaces = one_ancestors.each_extended_interface.flat_map do |interface|
+            other_interfaces = ancestor_builder.interface_ancestors(interface.name).ancestors #: Array[Definition::Ancestor::Instance]
+            other_interfaces = other_interfaces.select {|ancestor| ancestor.source }
+            [interface, *other_interfaces]
+          end
+          interface_methods = interface_methods(all_interfaces)
           import_methods(definition, type_name, methods, interface_methods, Substitution.new)
 
           entry.decls.each do |d|

test/rbs/definition_builder_test.rb

@@ -2566,4 +2566,31 @@ def __id__: () -> void
       end
     end
   end
+
+  def test_extend_overload
+    SignatureManager.new do |manager|
+      manager.files[Pathname("foo.rbs")] = <<~EOF
+        module M
+          def f: () -> Integer
+        end
+        class A
+          extend M
+          def self.f: () -> String | ...
+        end
+      EOF
+
+      manager.build do |env|
+        builder = DefinitionBuilder.new(env: env)
+
+        builder.build_singleton(type_name("::A")).tap do |definition|
+          assert_instance_of Definition, definition
+
+          definition.methods[:f].tap do |method|
+            assert_equal [TypeName("::A"), TypeName("::M")], method.defs.map(&:defined_in)
+            assert_equal [TypeName("::A"), TypeName("::A")], method.defs.map(&:implemented_in)
+          end
+        end
+      end
+    end
+  end
 end