syntax_data: {"ast_node_type":"variable","tokens":[{"end":93,"kind":"keyword","start":0,"text":"while"}]}
source_snippet:     while let Some(((b_char, b_rest), (a_char, a_rest))) = b.split_last().zip(a.split_last())
context_before:     // Strip common suffix.
context_after:         && a_char == b_char