Unexpected errors when specifying method signatures in RBS and returning values with `return`

[whtsht]

Case 1
No error is expected, but the following error is reported:

#: (String) -> bool
def a(a)
  return false #=> [error] expected: bool; actual: bot
end

Suppressing the error in Case 1 is relatively straightforward. whtsht@c0e142e
However, as noted in the comment, this appears to be more of a workaround than a proper fix.

For example, Case 2 cannot be resolved by the same adjustment used for Case 1.

---

Case 2
No error is expected, but the following error is reported:

#: (bool) -> String | Integer
def foo(a)
  if a
    "true"
  else
    return 0 # => [error] expected: String; actual: Integer
  end
end

[mame]

Thank you!