Rails/SaveBang "use create! instead of create" false positive

[jas14]

The Rails/SaveBang cop has a false positive when the return value of a create call is checked immediately (i.e. without assignment to a variable).

---

Expected behavior

I expect the cop to not fire when the return value is checked immediately.

Actual behavior

The cope fires when the return value is checked immediately:

app/test.rb:4:15: C: Rails/SaveBang: Use create! instead of create if the return value is not checked.
  return if X.create.persisted?
              ^^^^^^

Steps to reproduce the problem

Enable the Rails/SaveBang cop and run on the following small repro case:

def savebang
  return if X.create.persisted?
  # ... other code
end

RuboCop version

$ bundle exec rubocop -V
0.79.0 (using Parser 2.7.0.2, running on ruby 2.6.5 x86_64-darwin18)