syntax_data: {"ast_node_type":"other","tokens":[{"end":76,"kind":"keyword","start":0,"text":"impl<I:"}]}
source_snippet: impl<I: Interner, E: rustc_serialize::Encoder> rustc_serialize::Encodable<E>
context_before: #[cfg(feature = "nightly")]
context_after:     for UnsafeBinderInner<I>