Parser_env.Eat
let token: env => unit;
let push_lex_mode: env => Lex_mode.t => unit;
let pop_lex_mode: env => unit;
let double_pop_lex_mode: env => unit;
let trailing_comments: env => list(Flow_ast.Comment.t(Loc.t));
let comments_until_next_line: env => list(Flow_ast.Comment.t(Loc.t));
let program_comments: env => list(Flow_ast.Comment.t(Loc.t));