diff --git a/core/main/private_spec.rb b/core/main/private_spec.rb
index 78c5d287d4..cac0645b40 100644
--- a/core/main/private_spec.rb
+++ b/core/main/private_spec.rb
@@ -32,8 +32,16 @@
     end
   end
 
-  it "returns Object" do
-    eval("private :main_public_method", TOPLEVEL_BINDING).should equal(Object)
+  ruby_version_is ''...'3.1' do
+    it "returns Object" do
+      eval("private :main_public_method", TOPLEVEL_BINDING).should equal(Object)
+    end
+  end
+
+  ruby_version_is '3.1' do
+    it "returns argument" do
+      eval("private :main_public_method", TOPLEVEL_BINDING).should equal(:main_public_method)
+    end
   end
 
   it "raises a NameError when at least one of given method names is undefined" do
diff --git a/core/main/public_spec.rb b/core/main/public_spec.rb
index bfc27a9e80..91f045dbab 100644
--- a/core/main/public_spec.rb
+++ b/core/main/public_spec.rb
@@ -32,10 +32,19 @@
     end
   end
 
-  it "returns Object" do
-    eval("public :main_private_method", TOPLEVEL_BINDING).should equal(Object)
+  ruby_version_is ''...'3.1' do
+    it "returns Object" do
+      eval("public :main_private_method", TOPLEVEL_BINDING).should equal(Object)
+    end
   end
 
+  ruby_version_is '3.1' do
+    it "returns argument" do
+      eval("public :main_private_method", TOPLEVEL_BINDING).should equal(:main_private_method)
+    end
+  end
+
+
   it "raises a NameError when given an undefined name" do
     -> do
       eval "public :main_undefined_method", TOPLEVEL_BINDING
diff --git a/core/module/module_function_spec.rb b/core/module/module_function_spec.rb
index 407237d48f..0602e95ca9 100644
--- a/core/module/module_function_spec.rb
+++ b/core/module/module_function_spec.rb
@@ -38,14 +38,23 @@ def test3() end
     m.respond_to?(:test3).should == false
   end
 
-  it "returns the current module" do
-    x = nil
-    m = Module.new do
-      def test()  end
-      x = module_function :test
+  ruby_version_is ""..."3.1" do
+    it "returns self" do
+      Module.new do
+        def foo; end
+        module_function(:foo).should equal(self)
+      end
     end
+  end
 
-    x.should == m
+  ruby_version_is "3.1" do
+    it "returns argument or arguments if given" do
+      Module.new do
+        def foo; end
+        module_function(:foo).should equal(:foo)
+        module_function(:foo, :foo).should == [:foo, :foo]
+      end
+    end
   end
 
   it "creates an independent copy of the method, not a redirect" do
@@ -160,13 +169,20 @@ def test2() end
     m.respond_to?(:test2).should == true
   end
 
-  it "returns the current module" do
-    x = nil
-    m = Module.new {
-      x = module_function
-    }
+  ruby_version_is ""..."3.1" do
+    it "returns self" do
+      Module.new do
+        module_function.should equal(self)
+      end
+    end
+  end
 
-    x.should == m
+  ruby_version_is "3.1" do
+    it "returns nil" do
+      Module.new do
+        module_function.should equal(nil)
+      end
+    end
   end
 
   it "stops creating module functions if the body encounters another toggle " \
diff --git a/core/module/private_spec.rb b/core/module/private_spec.rb
index e893c24f38..ead806637c 100644
--- a/core/module/private_spec.rb
+++ b/core/module/private_spec.rb
@@ -38,11 +38,25 @@ class << obj
                   :module_specs_public_method_on_object_for_kernel_private)
   end
 
-  it "returns self" do
-    (class << Object.new; self; end).class_eval do
-      def foo; end
-      private(:foo).should equal(self)
-      private.should equal(self)
+  ruby_version_is ""..."3.1" do
+    it "returns self" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        private(:foo).should equal(self)
+        private.should equal(self)
+      end
+    end
+  end
+
+  ruby_version_is "3.1" do
+    it "returns argument or arguments if given" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        private(:foo).should equal(:foo)
+        private([:foo, :foo]).should == [:foo, :foo]
+        private(:foo, :foo).should == [:foo, :foo]
+        private.should equal(nil)
+      end
     end
   end
 
diff --git a/core/module/protected_spec.rb b/core/module/protected_spec.rb
index aa04a42fb8..058d49d751 100644
--- a/core/module/protected_spec.rb
+++ b/core/module/protected_spec.rb
@@ -39,11 +39,25 @@ class << ModuleSpecs::Parent
                   :module_specs_public_method_on_object_for_kernel_protected)
   end
 
-  it "returns self" do
-    (class << Object.new; self; end).class_eval do
-      def foo; end
-      protected(:foo).should equal(self)
-      protected.should equal(self)
+  ruby_version_is ""..."3.1" do
+    it "returns self" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        protected(:foo).should equal(self)
+        protected.should equal(self)
+      end
+    end
+  end
+
+  ruby_version_is "3.1" do
+    it "returns argument or arguments if given" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        protected(:foo).should equal(:foo)
+        protected([:foo, :foo]).should == [:foo, :foo]
+        protected(:foo, :foo).should == [:foo, :foo]
+        protected.should equal(nil)
+      end
     end
   end
 
diff --git a/core/module/public_spec.rb b/core/module/public_spec.rb
index e7059f6aa6..e3b183f228 100644
--- a/core/module/public_spec.rb
+++ b/core/module/public_spec.rb
@@ -27,12 +27,25 @@
                   :module_specs_private_method_on_object_for_kernel_public)
   end
 
-  it "returns self" do
-    (class << Object.new; self; end).class_eval do
-      def foo; end
-      private :foo
-      public(:foo).should equal(self)
-      public.should equal(self)
+  ruby_version_is ""..."3.1" do
+    it "returns self" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        public(:foo).should equal(self)
+        public.should equal(self)
+      end
+    end
+  end
+
+  ruby_version_is "3.1" do
+    it "returns argument or arguments if given" do
+      (class << Object.new; self; end).class_eval do
+        def foo; end
+        public(:foo).should equal(:foo)
+        public([:foo, :foo]).should == [:foo, :foo]
+        public(:foo, :foo).should == [:foo, :foo]
+        public.should equal(nil)
+      end
     end
   end