Allow to include uninitialized modules [Bug #18177]

The module that is about to be included is considered initialized.

1 files changed, 12 insertions, 0 deletions

diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index b36b8b7810..385d8dddfe 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -432,6 +432,18 @@ class TestModule < Test::Unit::TestCase
         initialize_copy(Module.new)
       end
     end
+
+    m = Class.new(Module) do
+      def initialize_copy(other)
+        # leave uninitialized
+      end
+    end.new.dup
+    c = Class.new
+    assert_operator(c.include(m), :<, m)
+    cp = Module.instance_method(:initialize_copy)
+    assert_raise(TypeError) do
+      cp.bind_call(m, Module.new)
+    end
   end
 
   def test_dup