syntax_data: {"ast_node_type":"other","tokens":[{"end":89,"kind":"keyword","start":0,"text":"user_provided_types.get(fun.hir_id).copied().map(|mut"}]}
source_snippet:                             user_provided_types.get(fun.hir_id).copied().map(|mut u_ty| {
context_before:                         let user_ty =
context_after:                                 if let ty::UserTypeKind::TypeOf(did, _) = &mut u_ty.value.kind {