Improve constant lookup in SourceFinder

[tompng]

Improve show_source of constant to find const owner more precise.

Constant lookup does not depend on self, but on Module.nesting

X = 1
class A
  Y = 1
  class B
    Z = 1
    [X, Y, Z] # these are visible here. Module.nesting #=> [A::B, A]
  end
end

class A::B
  # [X, Z] # Y is not visible here. Module.nesting #=> [A::B]
end

In this test code I added, X, Y, Z, Array are all visible with value == 1

X = 1
module M
  Y = 1
  Z = 2
end
class A
  Z = 1
  Array = 1
  class B
    include M
    Object.new.instance_eval { binding.irb }
  end
end

Module.nesting is [A::B, A] and lookup order seems A::B → A → A::B.ancestors → A.ancestors → TOPLEVEL(Object)

[st0012]

In this case, the result of this should be the same as eval_receiver_or_owner(signature)? If that's the case, maybe we can store that and use it here?

[tompng]

If signature == 'A::B::C', parts.join('::') will be 'A::B'
We need to evaluate A::B in current binding and get base = FooBar::A::B (FooBar part depends on binding's Module.nesting)
Now we can find source by calling base.const_source_location('C')

[st0012]

I see, thanks for explaining 👍

[st0012]

nit: I think having these parentheses introduces a new style that didn't exist in this repo before 🤔 ?

[tompng]

Updated to

a =
  if cond
  else
  end

style