syntax_data: {"ast_node_type":"other","tokens":[{"end":77,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // type, add an ascription node (e.g. `<Foo<'a> as MyTrait>::CONST`).
context_before:         // If this is an associated constant with an explicit user-written
context_after:         if let Some(&user_ty) = user_ty {