syntax_data: {"ast_node_type":"other","tokens":[{"end":42,"kind":"keyword","start":0,"text":"#[cfg(not(feature"}]}
source_snippet:             #[cfg(not(feature = "rustc"))]
context_before:             let mut set = rustc_data_structures::fx::FxIndexSet::default();
context_after:             let mut set = std::collections::HashSet::new();