Replace more mk_foo calls with infer_foo.

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1608,7 +1608,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             .collect::<SmallVec<[_; 8]>>();
         v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
         v.dedup();
-        let existential_predicates = tcx.mk_poly_existential_predicates(v.into_iter());
+        let existential_predicates = tcx.intern_poly_existential_predicates(&v);
 
         // Use explicitly-specified region bound.
         let region_bound = if !lifetime.is_elided() {

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -1936,7 +1936,7 @@ pub(super) fn check_type_bounds<'tcx>(
             .into()
         }
     });
-    let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter());
+    let bound_vars = tcx.intern_bound_variable_kinds(&bound_vars);
     let impl_ty_substs = tcx.intern_substs(&substs);
     let container_id = impl_ty.container_id(tcx);
 

compiler/rustc_hir_analysis/src/check/intrinsic.rs

@@ -137,14 +137,10 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
     let intrinsic_name = tcx.item_name(intrinsic_id);
     let name_str = intrinsic_name.as_str();
 
-    let bound_vars = tcx.mk_bound_variable_kinds(
+    let bound_vars = tcx.intern_bound_variable_kinds(&[
-        [
         ty::BoundVariableKind::Region(ty::BrAnon(0, None)),
         ty::BoundVariableKind::Region(ty::BrEnv),
-        ]
+    ]);
-        .iter()
-        .copied(),
-    );
     let mk_va_list_ty = |mutbl| {
         tcx.lang_items().va_list().map(|did| {
             let region = tcx.mk_re_late_bound(

compiler/rustc_hir_typeck/src/generator_interior/mod.rs

@@ -312,7 +312,7 @@ pub fn resolve_interior<'a, 'tcx>(
 
     // Extract type components to build the witness type.
     let type_list = fcx.tcx.mk_type_list(type_causes.iter().map(|cause| cause.ty));
-    let bound_vars = fcx.tcx.mk_bound_variable_kinds(bound_vars.into_iter());
+    let bound_vars = fcx.tcx.intern_bound_variable_kinds(&bound_vars);
     let witness =
         fcx.tcx.mk_generator_witness(ty::Binder::bind_with_vars(type_list, bound_vars.clone()));
 

compiler/rustc_middle/src/ty/context.rs

@@ -2399,13 +2399,13 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn late_bound_vars(self, id: HirId) -> &'tcx List<ty::BoundVariableKind> {
-        self.mk_bound_variable_kinds(
+        self.intern_bound_variable_kinds(
-            self.late_bound_vars_map(id.owner)
+            &self
+                .late_bound_vars_map(id.owner)
                 .and_then(|map| map.get(&id.local_id).cloned())
                 .unwrap_or_else(|| {
                     bug!("No bound vars found for {}", self.hir().node_to_string(id))
-                })
+                }),
-                .into_iter(),
         )
     }
 

compiler/rustc_mir_build/src/thir/cx/mod.rs

@@ -133,9 +133,9 @@ impl<'tcx> Cx<'tcx> {
                     bug!("closure expr does not have closure type: {:?}", closure_ty);
                 };
 
-                let bound_vars = self.tcx.mk_bound_variable_kinds(std::iter::once(
+                let bound_vars = self
-                    ty::BoundVariableKind::Region(ty::BrEnv),
+                    .tcx
-                ));
+                    .intern_bound_variable_kinds(&[ty::BoundVariableKind::Region(ty::BrEnv)]);
                 let br = ty::BoundRegion {
                     var: ty::BoundVar::from_usize(bound_vars.len() - 1),
                     kind: ty::BrEnv,

compiler/rustc_trait_selection/src/traits/select/confirmation.rs

@@ -564,10 +564,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                 .into()
                             }
                         });
-                        let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter());
+                        let bound_vars = tcx.intern_bound_variable_kinds(&bound_vars);
                         let assoc_ty_substs = tcx.intern_substs(&substs);
 
-                        let bound_vars = tcx.mk_bound_variable_kinds(bound_vars.into_iter());
+                        let bound_vars = tcx.intern_bound_variable_kinds(&bound_vars);
                         let bound =
                             bound.map_bound(|b| b.kind().skip_binder()).subst(tcx, assoc_ty_substs);
                         tcx.mk_predicate(ty::Binder::bind_with_vars(bound, bound_vars))

src/tools/clippy/clippy_lints/src/redundant_slicing.rs

@@ -11,8 +11,6 @@ use rustc_middle::ty::adjustment::{Adjust, AutoBorrow, AutoBorrowMutability};
 use rustc_middle::ty::subst::GenericArg;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use std::iter;
-
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for redundant slicing expressions which use the full range, and
@@ -136,7 +134,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantSlicing {
                 } else if let Some(target_id) = cx.tcx.lang_items().deref_target() {
                     if let Ok(deref_ty) = cx.tcx.try_normalize_erasing_regions(
                         cx.param_env,
-                        cx.tcx.mk_projection(target_id, cx.tcx.mk_substs(iter::once(GenericArg::from(indexed_ty)))),
+                        cx.tcx.mk_projection(target_id, cx.tcx.intern_substs(&[GenericArg::from(indexed_ty)])),
                     ) {
                         if deref_ty == expr_ty {
                             let snip = snippet_with_context(cx, indexed.span, ctxt, "..", &mut app).0;

src/tools/miri/src/eval.rs

@@ -363,7 +363,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
                 tcx,
                 ty::ParamEnv::reveal_all(),
                 start_id,
-                tcx.mk_substs(::std::iter::once(ty::subst::GenericArg::from(main_ret_ty))),
+                tcx.intern_substs(&[ty::subst::GenericArg::from(main_ret_ty)]),
             )
             .unwrap()
             .unwrap();