Ruby

Complex::compatible, unknown, Rational::compatible were removed by Ruby 2.6.0. fatal is still documented, but that exists even though you cannot reference it directly:

f = ObjectSpace.each_object(Class){|c| break c if c.name && c.name.downcase == c.name} # => fatal f.ancestors # => [fatal, Exception, Object, Kernel, BasicObject] 

The documentation for fatal states You are not able to rescue fatal. That appears to be incorrect:

f = ObjectSpace.each_object(Class){|c| break c if c.name && c.name.downcase == c.name} begin raise f rescue f 2 end # => 2 

Attached is a patch that removes that sentence from fatal's documentation. I'm not sure if we actually want to prevent the rescuing of fatal instead, though.

Applied in changeset git|404850e13446c79fb6142f1b32b219753e5cd726.

Remove documentation that fatal cannot be rescued [ci skip]

You can rescue it:

f = ObjectSpace.each_object(Class){|c| break c if c.name == 'fatal'}
begin
raise f
rescue f
2
end # => 2

It's not a good idea to rescue fatal exceptions you didn't generate
yourself, though.

Fixes [Bug #10691]