Use ItemCtxt::lower_ty over <dyn HirTyLowerer<'_>>::lower_ty

Simplifies the code.

Author: fmease

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -108,9 +108,7 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
                 .unwrap()
                 .0
                 .def_id;
-            let item_ctxt =
-                &ItemCtxt::new(tcx, item_def_id) as &dyn crate::hir_ty_lowering::HirTyLowerer<'_>;
-            let ty = item_ctxt.lower_ty(hir_ty);
+            let ty = ItemCtxt::new(tcx, item_def_id).lower_ty(hir_ty);
 
             // Iterate through the generics of the projection to find the one that corresponds to
             // the def_id that this query was called with. We filter to only type and const args here

compiler/rustc_hir_analysis/src/lib.rs

@@ -109,8 +109,6 @@ use rustc_span::{symbol::sym, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits;
 
-use hir_ty_lowering::HirTyLowerer;
-
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
 
 fn require_c_abi_if_c_variadic(tcx: TyCtxt<'_>, decl: &hir::FnDecl<'_>, abi: Abi, span: Span) {
@@ -207,6 +205,5 @@ pub fn lower_ty<'tcx>(tcx: TyCtxt<'tcx>, hir_ty: &hir::Ty<'tcx>) -> Ty<'tcx> {
     // def-ID that will be used to determine the traits/predicates in
     // scope. This is derived from the enclosing item-like thing.
     let env_def_id = tcx.hir().get_parent_item(hir_ty.hir_id);
-    let item_cx = self::collect::ItemCtxt::new(tcx, env_def_id.def_id);
-    item_cx.lowerer().lower_ty(hir_ty)
+    collect::ItemCtxt::new(tcx, env_def_id.def_id).lower_ty(hir_ty)
 }