false positive for Lint/ToEnumArguments when using sorbet

[dduugg]

Expected behavior

The "good" example for Lint/ToEnumArguments looks like this:

def foo(x, y = 1)
  to_enum(__callee__, x, y)
end

However, since __callee__ and __method__ can return nil, these are not viable in a type-checked ruby context, Sorbet in particular:

https://sorbet.run/#%23%20frozen_string_literal%3A%20true%0A%0Aextend%20T%3A%3ASig%0A%0Adef%20foo%28x%2C%20y%20%3D%201%29%0A%20%20to_enum%28__callee__%2C%20x%2C%20y%29%0Aend%0A%0Adef%20bar%28x%2C%20y%20%3D%201%29%0A%20%20to_enum%28T.must%28__callee__%29%2C%20x%2C%20y%29%0Aend

Instead, the __callee__ invocation has to be asserted as non-nil, by wrapping in T.must:

def for(x, y = 1)
  to_enum(T.must(__callee__), x, y)
end

I believe that this formulation should be accepted by rubocop.

Actual behavior

The last example above triggers a rubocop violation:

foo.rb:10:3: W: Lint/ToEnumArguments: Ensure you correctly provided all the arguments.
  to_enum(T.must(__callee__), x, y)
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Steps to reproduce the problem

Invoke rubocop foo.rb --only Lint/ToEnumArguments, where foo.rb contains the following:

def bar(x, y = 1)
  to_enum(T.must(__callee__), x, y)
end

RuboCop version

$ rubocop -V
1.45.1 (using Parser 3.2.0.0, rubocop-ast 1.24.1, running on ruby 3.1.1) [x86_64-darwin21]