syntax_data: {"ast_node_type":"other","tokens":[{"end":73,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                 // Make sure that inferred closure args have no type span
context_before:                 .get(index)
context_after:                 .and_then(|ty| if param.pat.span != ty.span { Some(ty.span) } else { None });