Bug #20307
Updated by nobu (Nobuyoshi Nakada) 3 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.compare_by_identity? # => false
p h["a"] # => 0
k.upcase!
# `k` is still in `h`.
p h.keys.include?(k) # => true
# but not found.
p((h.fetch(k) rescue $!)) # => #<KeyError: key not found: "A">
h["A"] = 1
p h # => {"A"=>0, "A"=>1}
```
I expect that `h.fetch(k)` returns `0` and `h` to still have `"a"=>0` has just one entry.