syntax_data: {"ast_node_type":"other","tokens":[{"end":46,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // Look for the first element that changed
context_before:     let mut iter = slice.iter().copied();
context_after:     match iter.by_ref().enumerate().find_map(|(i, t)| match t.try_fold_with(folder) {