syntax_data: {"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"Bound(d,"}]}
source_snippet:             Bound(d, b) => crate::debug_bound_var(f, *d, b),
context_before:             Param(p) => write!(f, "{p:?}"),
context_after:             Placeholder(p) => write!(f, "{p:?}"),