syntax_data: {"ast_node_type":"other","tokens":[{"end":38,"kind":"keyword","start":0,"text":"just_after_pat_pos"}]}
source_snippet:                     just_after_pat_pos
context_before:                 let just_after_pat_plus_ws = if include_whitespace {
context_after:                         + prev_source[just_after_pat_pos..]