syntax_data: {"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let db = ty::DebruijnIndex::from_usize(
context_before:                         .unwrap_or_else(|| bug!("Unexpected placeholder universe."));
context_after:                         self.universe_indices.len() - index + self.current_index.as_usize() - 1,