Problem

Related grammar:

  extras: ($) => [/[ \t]/, $.comment],
  ...
  ctrl_error: ($) =>
    seq(
      "error",
      "make",
      optional($._flag),  // <--- works fine without this line
      field("error_record", $.val_record),
    ),

You can see that the "make" token starts early at [0, 5] instead of [0, 9].

If I remove the line of optional($._flag), it outputs correct region again.

The code of the _flag rule is here, I think it has nothing to do with whitespaces.

Steps to reproduce

git clone https://github.com/nushell/tree-sitter-nu
cd tree-sitter-nu
tree-sitter generate

Expected behavior

The "make" token should start at [0, 9] as expected.

Tree-sitter version (tree-sitter --version)

tree-sitter 0.24.3

Operating system/version

macOS 15.1.1