self refers to current class

[handsomecheung]

class Base
  def self.get
    self.value
  end

  def self.value
    :hello
  end
end

class Upper1 < Base
  def self.value
    "hello"
  end
end

Upper1.get         # () -> symbol

The type of Upper1.get should be string. I add a binding self to current class (Upper1) to make the type right.

But this change will trigger a new issue:

class Upper1 < Base
  def self.value
    "hello"
  end
end

class Upper2 < Base
  def self.value
    11235
  end
end

Upper1.get    # () -> str
Upper2.get    # () -> str

Upper1.get and Upper2.share the same base method Base.get, so they are same type because of cache.

I don't know how to solve this issue simply, maybe change structure of arrows?

[yinwang0]

Ideally this can return a union type. But we can leave it this way now because the code requiring a union type in fields is bad style.