syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Ensure indexes are also not malformed.
context_before:         debug!("source_len=`{:?}`", source_len);
context_after:         if start_index > end_index || end_index > source_len - 1 {