syntax_data: {"ast_node_type":"import","tokens":[{"end":62,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // Some of the $ty arguments may not actually use 'tcx
context_before:     ($($ty:ty),+) => {
context_after:         $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {