syntax_data: {"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"ty::ExistentialTraitRef::erase_self_ty(tcx,"}]}
source_snippet:                         ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
context_before:                     let hr_source_principal = upcast_principal.map_bound(|trait_ref| {
context_after:                     });