Fix Complex and Rational are duplicable?

See [this test](https://gist.github.com/utilum/78918f1b64f8b61ee732cb266db7c43a).

1 files changed, 20 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/core_ext/object/duplicable.rb b/activesupport/lib/active_support/core_ext/object/duplicable.rb
index ebe31b38ca..c671d34673 100644
--- a/activesupport/lib/active_support/core_ext/object/duplicable.rb
+++ b/activesupport/lib/active_support/core_ext/object/duplicable.rb
@@ -121,3 +121,23 @@ class Method
     false
   end
 end
+
+class Complex
+  # Complexes are not duplicable:
+  #
+  # Complex(1).duplicable? # => false
+  # Complex(1).dup         # => TypeError: can't copy Complex
+  def duplicable?
+    false
+  end
+end
+
+class Rational
+  # Rationals are not duplicable:
+  #
+  # Rational(1).duplicable? # => false
+  # Rational(1).dup         # => TypeError: can't copy Rational
+  def duplicable?
+    false
+  end
+end