syntax_data: {"ast_node_type":"variable","tokens":[{"end":67,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let (head, rest) = branches.split_first().unwrap();
context_before:             let (variant_idx, branches) = if def.is_enum() {
context_after:                 (VariantIdx::from_u32(head.unwrap_leaf().to_u32()), rest)