syntax_data: {"ast_node_type":"variable","tokens":[{"end":46,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let pos = self.relative_position(pos);
context_before:     pub fn lookup_file_pos_with_col_display(&self, pos: BytePos) -> (usize, CharPos, usize) {
context_after:         let (line, col_or_chpos) = self.lookup_file_pos(pos);