syntax_data: {"ast_node_type":"other","tokens":[{"end":98,"kind":"keyword","start":0,"text":".instantiate_bound_regions_with_erased(tcx.fn_sig(def_id).instantiate(tcx,"}]}
source_snippet:                 .instantiate_bound_regions_with_erased(tcx.fn_sig(def_id).instantiate(tcx, args));
context_before:             let mut sig = tcx