syntax_data: {"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let just_after_pat_plus_ws = if include_whitespace {
context_before:                 let just_after_pat_pos = pat_pos + pat.len() - 1;
context_after:                     just_after_pat_pos