There's no symbol table in the parser, so at parse time, we don't distinguish those cases:

  $ cat test.rb
  module Test
    def test1
      x = 14; x
    end

    def test2
      y = 14; x
    end
  end
  $ tree-sitter parse test.rb
  (program [0, 0] - [9, 0]
    (module [0, 0] - [8, 3]
      name: (constant [0, 7] - [0, 11])
      (method [1, 2] - [3, 5]
        name: (identifier [1, 6] - [1, 11])
        (assignment [2, 4] - [2, 10]
          left: (identifier [2, 4] - [2, 5])
          right: (integer [2, 8] - [2, 10]))
        (identifier [2, 12] - [2, 13]))
      (method [5, 2] - [7, 5]
        name: (identifier [5, 6] - [5, 11])
        (assignment [6, 4] - [6, 10]
          left: (identifier [6, 4] - [6, 5])
          right: (integer [6, 8] - [6, 10]))
        (identifier [6, 12] - [6, 13]))))

For some use cases (e.g. syntax highlighting, depending on your colorization rules) it doesn't matter, and so we don't want to pay the cost. If it does matter (like in an actual implementation), then you'd have to implement this yourself and drive it by the parse tree you get from tree-sitter.