syntax_data: {"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"tcx.struct_lockstep_tails_raw(source,"}]}
source_snippet:         tcx.struct_lockstep_tails_raw(source, target, |ty| {
context_before:         let tcx = self;
context_after:             tcx.normalize_erasing_regions(typing_env, ty)