ty::Bool => Some(0),
ty::Char => Some(1),
ty::Str => Some(2),
- ty::Adt(def, _) if tcx.is_diagnostic_item(sym::String, def.did()) => Some(2),
+ ty::Adt(def, _) if Some(def.did()) == tcx.lang_items().string() => Some(2),
ty::Int(..)
| ty::Uint(..)
| ty::Float(..)