"alias:" production emitted in many places

[seh]

I noticed that when I inspect the s-expression view of tree-sitter parse, before a top-level struct and before each field in a struct I see the tag "alias". For the following input file, I see the output that follows:

{
   id: 1
}

alias: 
 (struct_lit {
  alias: 
   (field
    (label (identifier))
    :
    (value (number)))
  })

What do the "alias:" lines mean there on the first and third lines? Is that tree-sitter indicating that an optional identifier and following = character are acceptable there but absent?

[eonpatapon]

Not sure why you get this output, do you use tip, which version of tree-sitter ?

alias: should be seen when some cue alias is defined like:

✦ tree-sitter --version
tree-sitter 0.20.8

✦ cat test.cue 
{
	id: 1
	FirstAlias=b: 2
}

[SecondAlias=string]: int


✦ tree-sitter parse test.cue 

(source_file [0, 0] - [6, 0]
  (struct_lit [0, 0] - [3, 1]
    (field [1, 1] - [1, 6]
      (label [1, 1] - [1, 3]
        (identifier [1, 1] - [1, 3]))
      (value [1, 5] - [1, 6]
        (int_lit [1, 5] - [1, 6])))
    (field [2, 1] - [2, 16]
      (label [2, 1] - [2, 13]
        alias: (identifier [2, 1] - [2, 11])
        (identifier [2, 12] - [2, 13]))
      (value [2, 15] - [2, 16]
        (int_lit [2, 15] - [2, 16]))))
  (field [5, 0] - [5, 25]
    (label [5, 0] - [5, 20]
      (optional [5, 1] - [5, 19]
        alias: (identifier [5, 1] - [5, 12])
        (string_type [5, 13] - [5, 19])))
    (value [5, 22] - [5, 25]
      (int_type [5, 22] - [5, 25]))))

[seh]

Not sure why you get this output, do you use tip, which version of tree-sitter?

I think it was the Emacs treesit-auto package that took care of downloading and building the library, so it probably pulled the head revision here.

I see the output via Emacs's treesit-explore-mode. I had installed tree-sitter-cli via npm, presumably at version 0.20.8.