Bug #20307
Updated by nobu (Nobuyoshi Nakada) 11 months ago
I don't think this behavior is expected.
```ruby
i = Hash.new.compare_by_identity
k = "a"
i[k] = 0
h = {}.update(i)
p h["a"] # => 0
k.upcase!
p h.keys.include?(k) # => true
p h.fetch(k) # in 'Hash#fetch': key not found: "A" (KeyError)
```