Ruby

Since the implementation of feature #12979, #dup and #clone on Integer and Float do not raise a TypeError anymore, and silently return self. Rational and Complex still raise an exception.

I'm not sure whether this inconsistent behavior is intended or only an oversight. I guess all Numeric classes should behave in a similar way?

Additionally, what is the intention regarding the returned object for non-immediate numeric values, should they return self or a new object?
At the time being, BigDecimal (which already did allow #dup/#clone before the change) returns a new object, while Bignum integers return self.

Current behavior:

RUBY_VERSION # => "2.4.0" 1.dup # => 1 1.clone # => 1 1.5.dup # => 1.5 1.5.clone # => 1.5 Rational(1).dup rescue $! # => #<TypeError: can't copy Rational> Rational(1).clone rescue $! # => #<TypeError: can't copy Rational> Complex(1).dup rescue $! # => #<TypeError: can't copy Complex> Complex(1).clone rescue $! # => #<TypeError: can't copy Complex> require "bigdecimal" BigDecimal(1).dup # => 0.1e1 BigDecimal(1).clone # => 0.1e1 d = (1<<64) [d.object_id, d.dup.object_id, d.clone.object_id] # => [5134140, 5134140, 5134140] d = BigDecimal(1) [d.object_id, d.dup.object_id, d.clone.object_id] # => [5133040, 5132900, 5132840] 

Old behavior:

RUBY_VERSION # => "2.3.3" 1.dup rescue $! # => #<TypeError: can't dup Fixnum> 1.clone rescue $! # => #<TypeError: can't clone Fixnum> 1.5.dup rescue $! # => #<TypeError: can't dup Float> 1.5.clone rescue $! # => #<TypeError: can't clone Float> Rational(1).dup rescue $! # => #<TypeError: can't copy Rational> Rational(1).clone rescue $! # => #<TypeError: can't copy Rational> Complex(1).dup rescue $! # => #<TypeError: can't copy Complex> Complex(1).clone rescue $! # => #<TypeError: can't copy Complex> require "bigdecimal" BigDecimal(1).dup # => #<BigDecimal:101e270,'0.1E1',9(27)> BigDecimal(1).clone # => #<BigDecimal:101dfa0,'0.1E1',9(27)>