Use &'hir Ty everywhere.

For consistency, and because it makes HIR measurement simpler and more
accurate.

compiler/rustc_ast_lowering/src/lib.rs

@@ -1152,7 +1152,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }
                     _ => {}
                 }
-                GenericArg::Type(self.lower_ty_direct(&ty, itctx))
+                GenericArg::Type(self.lower_ty(&ty, itctx))
             }
             ast::GenericArg::Const(ct) => GenericArg::Const(ConstArg {
                 value: self.lower_anon_const(&ct),

compiler/rustc_ast_lowering/src/path.rs

@@ -359,7 +359,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             }
             FnRetTy::Default(_) => self.arena.alloc(self.ty_tup(*span, &[])),
         };
-        let args = smallvec![GenericArg::Type(self.ty_tup(*inputs_span, inputs))];
+        let args = smallvec![GenericArg::Type(self.arena.alloc(self.ty_tup(*inputs_span, inputs)))];
         let binding = self.output_ty_binding(output_ty.span, output_ty);
         (
             GenericArgsCtor {

compiler/rustc_hir/src/hir.rs

@@ -265,7 +265,7 @@ impl InferArg {
 #[derive(Debug, HashStable_Generic)]
 pub enum GenericArg<'hir> {
     Lifetime(Lifetime),
-    Type(Ty<'hir>),
+    Type(&'hir Ty<'hir>),
     Const(ConstArg),
     Infer(InferArg),
 }
@@ -3502,7 +3502,7 @@ mod size_asserts {
     static_assert_size!(FnDecl<'_>, 40);
     static_assert_size!(ForeignItem<'_>, 72);
     static_assert_size!(ForeignItemKind<'_>, 40);
-    static_assert_size!(GenericArg<'_>, 80);
+    static_assert_size!(GenericArg<'_>, 40);
     static_assert_size!(GenericBound<'_>, 48);
     static_assert_size!(Generics<'_>, 56);
     static_assert_size!(Impl<'_>, 80);

src/tools/clippy/clippy_lints/src/manual_bits.rs

@@ -105,7 +105,7 @@ fn get_size_of_ty<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<
         if let Some(def_id) = cx.qpath_res(count_func_qpath, count_func.hir_id).opt_def_id();
         if cx.tcx.is_diagnostic_item(sym::mem_size_of, def_id);
         then {
-            cx.typeck_results().node_substs(count_func.hir_id).types().next().map(|resolved_ty| (real_ty, resolved_ty))
+            cx.typeck_results().node_substs(count_func.hir_id).types().next().map(|resolved_ty| (*real_ty, resolved_ty))
         } else {
             None
         }

src/tools/clippy/clippy_utils/src/lib.rs

@@ -333,7 +333,7 @@ pub fn qpath_generic_tys<'tcx>(qpath: &QPath<'tcx>) -> impl Iterator<Item = &'tc
         .map_or(&[][..], |a| a.args)
         .iter()
         .filter_map(|a| match a {
-            hir::GenericArg::Type(ty) => Some(ty),
+            hir::GenericArg::Type(ty) => Some(*ty),
             _ => None,
         })
 }