Followed up bd6e1a0f0883dba7b02f30cefe5ebec96d02cb90

spec/ruby/library/ipaddr/new_spec.rb

@@ -77,6 +77,7 @@ describe "IPAddr#new" do
     a.family.should == Socket::AF_INET6
   end
 
+  ruby_version_is ""..."3.1" do
     it "raises on incorrect IPAddr strings" do
       [
         ["fe80::1%fxp0"],
@@ -90,4 +91,20 @@ describe "IPAddr#new" do
         }.should raise_error(ArgumentError)
       }
     end
+  end
+
+  ruby_version_is "3.1" do
+    it "raises on incorrect IPAddr strings" do
+      [
+        ["::1/255.255.255.0"],
+        [IPAddr.new("::1").to_i],
+        ["::ffff:192.168.1.2/120", Socket::AF_INET],
+        ["[192.168.1.2]/120"],
+      ].each { |args|
+        ->{
+          IPAddr.new(*args)
+        }.should raise_error(ArgumentError)
+      }
+    end
+  end
 end