Auto merge of #107869 - nnethercote:reduce-interning, r=compiler-errors

Reduce interning

r? `@compiler-errors`

30 files changed, 173 insertions, 114 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
index e9bc40c3310..708f3bc0c78 100644
--- a/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
@@ -385,10 +385,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     calculate_debuginfo_offset(bx, local, &var, base);
 
                 // Create a variable which will be a pointer to the actual value
-                let ptr_ty = bx.tcx().mk_ty(ty::RawPtr(ty::TypeAndMut {
-                    mutbl: mir::Mutability::Mut,
-                    ty: place.layout.ty,
-                }));
+                let ptr_ty = bx
+                    .tcx()
+                    .mk_ptr(ty::TypeAndMut { mutbl: mir::Mutability::Mut, ty: place.layout.ty });
                 let ptr_layout = bx.layout_of(ptr_ty);
                 let alloca = PlaceRef::alloca(bx, ptr_layout);
                 bx.set_var_name(alloca.llval, &(var.name.to_string() + ".dbg.spill"));
diff --git a/compiler/rustc_const_eval/src/const_eval/valtrees.rs b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
index c52886b77e6..fc546e4de0e 100644
--- a/compiler/rustc_const_eval/src/const_eval/valtrees.rs
+++ b/compiler/rustc_const_eval/src/const_eval/valtrees.rs
@@ -193,7 +193,7 @@ fn get_info_on_unsized_field<'tcx>(
 
     // Have to adjust type for ty::Str
     let unsized_inner_ty = match unsized_inner_ty.kind() {
-        ty::Str => tcx.mk_ty(ty::Uint(ty::UintTy::U8)),
+        ty::Str => tcx.types.u8,
         _ => unsized_inner_ty,
     };
 
@@ -216,7 +216,7 @@ fn create_pointee_place<'tcx>(
 
         let (unsized_inner_ty, num_elems) = get_info_on_unsized_field(ty, valtree, tcx);
         let unsized_inner_ty = match unsized_inner_ty.kind() {
-            ty::Str => tcx.mk_ty(ty::Uint(ty::UintTy::U8)),
+            ty::Str => tcx.types.u8,
             _ => unsized_inner_ty,
         };
         let unsized_inner_ty_size =
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index 8ca3fdf400e..bb4b7ad50b8 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -217,10 +217,10 @@ impl Qualif for CustomEq {
 
     fn in_adt_inherently<'tcx>(
         cx: &ConstCx<'_, 'tcx>,
-        adt: AdtDef<'tcx>,
+        def: AdtDef<'tcx>,
         substs: SubstsRef<'tcx>,
     ) -> bool {
-        let ty = cx.tcx.mk_ty(ty::Adt(adt, substs));
+        let ty = cx.tcx.mk_adt(def, substs);
         !ty.is_structural_eq_shallow(cx.tcx)
     }
 }
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 75cc7cbaa60..8c753a99a09 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -1250,7 +1250,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 //
                 // Calling `skip_binder` is okay, because `add_bounds` expects the `param_ty`
                 // parameter to have a skipped binder.
-                let param_ty = tcx.mk_ty(ty::Alias(ty::Projection, projection_ty.skip_binder()));
+                let param_ty = tcx.mk_alias(ty::Projection, projection_ty.skip_binder());
                 self.add_bounds(param_ty, ast_bounds.iter(), bounds, candidate.bound_vars());
             }
         }
@@ -2930,7 +2930,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     }
                 };
 
-                tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length))
+                tcx.mk_array_with_const_len(self.ast_ty_to_ty(ty), length)
             }
             hir::TyKind::Typeof(e) => {
                 let ty_erased = tcx.type_of(e.def_id);
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
index 640920638a7..c86af6a379b 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -1927,10 +1927,10 @@ pub(super) fn check_type_bounds<'tcx>(
             let kind = ty::BoundTyKind::Param(param.def_id, param.name);
             let bound_var = ty::BoundVariableKind::Ty(kind);
             bound_vars.push(bound_var);
-            tcx.mk_ty(ty::Bound(
+            tcx.mk_bound(
                 ty::INNERMOST,
                 ty::BoundTy { var: ty::BoundVar::from_usize(bound_vars.len() - 1), kind },
-            ))
+            )
             .into()
         }
         GenericParamDefKind::Lifetime => {
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 5b9b57da382..5f95622883b 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -603,8 +603,7 @@ fn gather_gat_bounds<'tcx, T: TypeFoldable<'tcx>>(
                 // our example, the type was `Self`, which will also be
                 // `Self` in the GAT.
                 let ty_param = gat_generics.param_at(*ty_idx, tcx);
-                let ty_param = tcx
-                    .mk_ty(ty::Param(ty::ParamTy { index: ty_param.index, name: ty_param.name }));
+                let ty_param = tcx.mk_ty_param(ty_param.index, ty_param.name);
                 // Same for the region. In our example, 'a corresponds
                 // to the 'me parameter.
                 let region_param = gat_generics.param_at(*region_a_idx, tcx);
diff --git a/compiler/rustc_hir_typeck/src/check.rs b/compiler/rustc_hir_typeck/src/check.rs
index cc515e6c853..05f6d8e6072 100644
--- a/compiler/rustc_hir_typeck/src/check.rs
+++ b/compiler/rustc_hir_typeck/src/check.rs
@@ -264,9 +264,7 @@ fn check_lang_start_fn<'tcx>(
         // for example `start`'s generic should be a type parameter
         let generics = tcx.generics_of(def_id);
         let fn_generic = generics.param_at(0, tcx);
-        let generic_tykind =
-            ty::Param(ty::ParamTy { index: fn_generic.index, name: fn_generic.name });
-        let generic_ty = tcx.mk_ty(generic_tykind);
+        let generic_ty = tcx.mk_ty_param(fn_generic.index, fn_generic.name);
         let expected_fn_sig =
             tcx.mk_fn_sig([].iter(), &generic_ty, false, hir::Unsafety::Normal, Abi::Rust);
         let expected_ty = tcx.mk_fn_ptr(Binder::dummy(expected_fn_sig));
diff --git a/compiler/rustc_hir_typeck/src/demand.rs b/compiler/rustc_hir_typeck/src/demand.rs
index c4905a934cb..ae00042eae7 100644
--- a/compiler/rustc_hir_typeck/src/demand.rs
+++ b/compiler/rustc_hir_typeck/src/demand.rs
@@ -273,12 +273,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             ct_op: |c| c,
             ty_op: |t| match *t.kind() {
                 ty::Infer(ty::TyVar(_)) => self.tcx.mk_ty_var(ty::TyVid::from_u32(0)),
-                ty::Infer(ty::IntVar(_)) => {
-                    self.tcx.mk_ty_infer(ty::IntVar(ty::IntVid { index: 0 }))
-                }
-                ty::Infer(ty::FloatVar(_)) => {
-                    self.tcx.mk_ty_infer(ty::FloatVar(ty::FloatVid { index: 0 }))
-                }
+                ty::Infer(ty::IntVar(_)) => self.tcx.mk_int_var(ty::IntVid { index: 0 }),
+                ty::Infer(ty::FloatVar(_)) => self.tcx.mk_float_var(ty::FloatVid { index: 0 }),
                 _ => t,
             },
         };
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index bb235a48361..12850c733e8 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1429,7 +1429,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
         self.check_repeat_element_needs_copy_bound(element, count, element_ty);
 
-        tcx.mk_ty(ty::Array(t, count))
+        tcx.mk_array_with_const_len(t, count)
     }
 
     fn check_repeat_element_needs_copy_bound(
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 52236ae56ee..3201035bdd8 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -1296,7 +1296,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             )
         });
         let element_tys = tcx.mk_type_list(element_tys_iter);
-        let pat_ty = tcx.mk_ty(ty::Tuple(element_tys));
+        let pat_ty = tcx.intern_tup(element_tys);
         if let Some(mut err) = self.demand_eqtype_pat_diag(span, expected, pat_ty, ti) {
             let reported = err.emit();
             // Walk subpatterns with an expected type of `err` in this case to silence
diff --git a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
index f1b32cd941e..c11dcc8587b 100644
--- a/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
+++ b/compiler/rustc_infer/src/infer/canonical/canonicalizer.rs
@@ -752,7 +752,7 @@ impl<'cx, 'tcx> Canonicalizer<'cx, 'tcx> {
             self.fold_ty(bound_to)
         } else {
             let var = self.canonical_var(info, ty_var.into());
-            self.tcx().mk_ty(ty::Bound(self.binder_index, var.into()))
+            self.tcx().mk_bound(self.binder_index, var.into())
         }
     }
 
diff --git a/compiler/rustc_infer/src/infer/canonical/mod.rs b/compiler/rustc_infer/src/infer/canonical/mod.rs
index f7e3e4a1cc0..d5cb3fb2498 100644
--- a/compiler/rustc_infer/src/infer/canonical/mod.rs
+++ b/compiler/rustc_infer/src/infer/canonical/mod.rs
@@ -124,7 +124,7 @@ impl<'tcx> InferCtxt<'tcx> {
             CanonicalVarKind::PlaceholderTy(ty::PlaceholderType { universe, name }) => {
                 let universe_mapped = universe_map(universe);
                 let placeholder_mapped = ty::PlaceholderType { universe: universe_mapped, name };
-                self.tcx.mk_ty(ty::Placeholder(placeholder_mapped)).into()
+                self.tcx.mk_placeholder(placeholder_mapped).into()
             }
 
             CanonicalVarKind::Region(ui) => self
diff --git a/compiler/rustc_infer/src/infer/freshen.rs b/compiler/rustc_infer/src/infer/freshen.rs
index 1c76950cc6c..073a2b0753d 100644
--- a/compiler/rustc_infer/src/infer/freshen.rs
+++ b/compiler/rustc_infer/src/infer/freshen.rs
@@ -58,14 +58,9 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
         }
     }
 
-    fn freshen_ty<F>(
-        &mut self,
-        opt_ty: Option<Ty<'tcx>>,
-        key: ty::InferTy,
-        freshener: F,
-    ) -> Ty<'tcx>
+    fn freshen_ty<F>(&mut self, opt_ty: Option<Ty<'tcx>>, key: ty::InferTy, mk_fresh: F) -> Ty<'tcx>
     where
-        F: FnOnce(u32) -> ty::InferTy,
+        F: FnOnce(u32) -> Ty<'tcx>,
     {
         if let Some(ty) = opt_ty {
             return ty.fold_with(self);
@@ -76,7 +71,7 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
             Entry::Vacant(entry) => {
                 let index = self.ty_freshen_count;
                 self.ty_freshen_count += 1;
-                let t = self.infcx.tcx.mk_ty_infer(freshener(index));
+                let t = mk_fresh(index);
                 entry.insert(t);
                 t
             }
@@ -204,7 +199,7 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
         match v {
             ty::TyVar(v) => {
                 let opt_ty = self.infcx.inner.borrow_mut().type_variables().probe(v).known();
-                Some(self.freshen_ty(opt_ty, ty::TyVar(v), ty::FreshTy))
+                Some(self.freshen_ty(opt_ty, ty::TyVar(v), |n| self.infcx.tcx.mk_fresh_ty(n)))
             }
 
             ty::IntVar(v) => Some(
@@ -216,7 +211,7 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
                         .probe_value(v)
                         .map(|v| v.to_type(self.infcx.tcx)),
                     ty::IntVar(v),
-                    ty::FreshIntTy,
+                    |n| self.infcx.tcx.mk_fresh_int_ty(n),
                 ),
             ),
 
@@ -229,7 +224,7 @@ impl<'a, 'tcx> TypeFreshener<'a, 'tcx> {
                         .probe_value(v)
                         .map(|v| v.to_type(self.infcx.tcx)),
                     ty::FloatVar(v),
-                    ty::FreshFloatTy,
+                    |n| self.infcx.tcx.mk_fresh_float_ty(n),
                 ),
             ),
 
diff --git a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
index 412e52d8fd7..39940f4592d 100644
--- a/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
+++ b/compiler/rustc_infer/src/infer/higher_ranked/mod.rs
@@ -88,10 +88,10 @@ impl<'tcx> InferCtxt<'tcx> {
                 }))
             },
             types: &mut |bound_ty: ty::BoundTy| {
-                self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
+                self.tcx.mk_placeholder(ty::PlaceholderType {
                     universe: next_universe,
                     name: bound_ty.kind,
-                }))
+                })
             },
             consts: &mut |bound_var: ty::BoundVar, ty| {
                 self.tcx
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index e77924900a0..ae196a7133c 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -2071,14 +2071,14 @@ fn replace_param_and_infer_substs_with_placeholder<'tcx>(
 
         fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
             if let ty::Infer(_) = t.kind() {
-                self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
+                self.tcx.mk_placeholder(ty::PlaceholderType {
                     universe: ty::UniverseIndex::ROOT,
                     name: ty::BoundTyKind::Anon({
                         let idx = self.idx;
                         self.idx += 1;
                         idx
                     }),
-                }))
+                })
             } else {
                 t.super_fold_with(self)
             }
diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index d6f20a8fc06..e6e4545d9c3 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -345,9 +345,9 @@ impl<'tcx> CanonicalVarValues<'tcx> {
             var_values: tcx.mk_substs(infos.iter().enumerate().map(
                 |(i, info)| -> ty::GenericArg<'tcx> {
                     match info.kind {
-                        CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => tcx
-                            .mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into()))
-                            .into(),
+                        CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
+                            tcx.mk_bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into()).into()
+                        }
                         CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
                             let br = ty::BoundRegion {
                                 var: ty::BoundVar::from_usize(i),
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index b5e0b88bbe5..9f544de9f87 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -162,7 +162,7 @@ impl<'tcx> Rvalue<'tcx> {
         match *self {
             Rvalue::Use(ref operand) => operand.ty(local_decls, tcx),
             Rvalue::Repeat(ref operand, count) => {
-                tcx.mk_ty(ty::Array(operand.ty(local_decls, tcx), count))
+                tcx.mk_array_with_const_len(operand.ty(local_decls, tcx), count)
             }
             Rvalue::ThreadLocalRef(did) => {
                 let static_ty = tcx.type_of(did);
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 04537ad635a..5962384241e 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -241,6 +241,11 @@ impl<'tcx> CtxtInterners<'tcx> {
     }
 }
 
+const NUM_PREINTERNED_TY_VARS: u32 = 100;
+const NUM_PREINTERNED_FRESH_TYS: u32 = 20;
+const NUM_PREINTERNED_FRESH_INT_TYS: u32 = 3;
+const NUM_PREINTERNED_FRESH_FLOAT_TYS: u32 = 3;
+
 pub struct CommonTypes<'tcx> {
     pub unit: Ty<'tcx>,
     pub bool: Ty<'tcx>,
@@ -266,7 +271,20 @@ pub struct CommonTypes<'tcx> {
     /// Dummy type used for the `Self` of a `TraitRef` created for converting
     /// a trait object, and which gets removed in `ExistentialTraitRef`.
     /// This type must not appear anywhere in other converted types.
+    /// `Infer(ty::FreshTy(0))` does the job.
     pub trait_object_dummy_self: Ty<'tcx>,
+
+    /// Pre-interned `Infer(ty::TyVar(n))` for small values of `n`.
+    pub ty_vars: Vec<Ty<'tcx>>,
+
+    /// Pre-interned `Infer(ty::FreshTy(n))` for small values of `n`.
+    pub fresh_tys: Vec<Ty<'tcx>>,
+
+    /// Pre-interned `Infer(ty::FreshIntTy(n))` for small values of `n`.
+    pub fresh_int_tys: Vec<Ty<'tcx>>,
+
+    /// Pre-interned `Infer(ty::FreshFloatTy(n))` for small values of `n`.
+    pub fresh_float_tys: Vec<Ty<'tcx>>,
 }
 
 pub struct CommonLifetimes<'tcx> {
@@ -289,6 +307,15 @@ impl<'tcx> CommonTypes<'tcx> {
     ) -> CommonTypes<'tcx> {
         let mk = |ty| interners.intern_ty(ty, sess, untracked);
 
+        let ty_vars =
+            (0..NUM_PREINTERNED_TY_VARS).map(|n| mk(Infer(ty::TyVar(TyVid::from(n))))).collect();
+        let fresh_tys: Vec<_> =
+            (0..NUM_PREINTERNED_FRESH_TYS).map(|n| mk(Infer(ty::FreshTy(n)))).collect();
+        let fresh_int_tys: Vec<_> =
+            (0..NUM_PREINTERNED_FRESH_INT_TYS).map(|n| mk(Infer(ty::FreshIntTy(n)))).collect();
+        let fresh_float_tys: Vec<_> =
+            (0..NUM_PREINTERNED_FRESH_FLOAT_TYS).map(|n| mk(Infer(ty::FreshFloatTy(n)))).collect();
+
         CommonTypes {
             unit: mk(Tuple(List::empty())),
             bool: mk(Bool),
@@ -311,7 +338,12 @@ impl<'tcx> CommonTypes<'tcx> {
             str_: mk(Str),
             self_param: mk(ty::Param(ty::ParamTy { index: 0, name: kw::SelfUpper })),
 
-            trait_object_dummy_self: mk(Infer(ty::FreshTy(0))),
+            trait_object_dummy_self: fresh_tys[0],
+
+            ty_vars,
+            fresh_tys,
+            fresh_int_tys,
+            fresh_float_tys,
         }
     }
 }
@@ -1604,6 +1636,7 @@ impl<'tcx> TyCtxt<'tcx> {
         if *r == kind { r } else { self.mk_region(kind) }
     }
 
+    // Avoid this in favour of more specific `mk_*` methods, where possible.
     #[allow(rustc::usage_of_ty_tykind)]
     #[inline]
     pub fn mk_ty(self, st: TyKind<'tcx>) -> Ty<'tcx> {
@@ -1756,17 +1789,22 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline]
+    pub fn mk_array_with_const_len(self, ty: Ty<'tcx>, ct: Const<'tcx>) -> Ty<'tcx> {
+        self.mk_ty(Array(ty, ct))
+    }
+
+    #[inline]
     pub fn mk_slice(self, ty: Ty<'tcx>) -> Ty<'tcx> {
         self.mk_ty(Slice(ty))
     }
 
     #[inline]
     pub fn intern_tup(self, ts: &[Ty<'tcx>]) -> Ty<'tcx> {
-        self.mk_ty(Tuple(self.intern_type_list(&ts)))
+        if ts.is_empty() { self.types.unit } else { self.mk_ty(Tuple(self.intern_type_list(&ts))) }
     }
 
     pub fn mk_tup<I: InternAs<Ty<'tcx>, Ty<'tcx>>>(self, iter: I) -> I::Output {
-        iter.intern_with(|ts| self.mk_ty(Tuple(self.intern_type_list(&ts))))
+        iter.intern_with(|ts| self.intern_tup(ts))
     }
 
     #[inline]
@@ -1830,7 +1868,7 @@ impl<'tcx> TyCtxt<'tcx> {
         item_def_id: DefId,
         substs: impl IntoIterator<Item = impl Into<GenericArg<'tcx>>>,
     ) -> Ty<'tcx> {
-        self.mk_ty(Alias(ty::Projection, self.mk_alias_ty(item_def_id, substs)))
+        self.mk_alias(ty::Projection, self.mk_alias_ty(item_def_id, substs))
     }
 
     #[inline]
@@ -1868,28 +1906,54 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline]
-    pub fn mk_ty_var(self, v: TyVid) -> Ty<'tcx> {
-        self.mk_ty_infer(TyVar(v))
+    pub fn mk_const(self, kind: impl Into<ty::ConstKind<'tcx>>, ty: Ty<'tcx>) -> Const<'tcx> {
+        self.mk_const_internal(ty::ConstData { kind: kind.into(), ty })
     }
 
     #[inline]
-    pub fn mk_const(self, kind: impl Into<ty::ConstKind<'tcx>>, ty: Ty<'tcx>) -> Const<'tcx> {
-        self.mk_const_internal(ty::ConstData { kind: kind.into(), ty })
+    pub fn mk_ty_var(self, v: TyVid) -> Ty<'tcx> {
+        // Use a pre-interned one when possible.
+        self.types.ty_vars.get(v.as_usize()).copied().unwrap_or_else(|| self.mk_ty(Infer(TyVar(v))))
     }
 
     #[inline]
     pub fn mk_int_var(self, v: IntVid) -> Ty<'tcx> {
-        self.mk_ty_infer(IntVar(v))
+        self.mk_ty(Infer(IntVar(v)))
     }
 
     #[inline]
     pub fn mk_float_var(self, v: FloatVid) -> Ty<'tcx> {
-        self.mk_ty_infer(FloatVar(v))
+        self.mk_ty(Infer(FloatVar(v)))
     }
 
     #[inline]
-    pub fn mk_ty_infer(self, it: InferTy) -> Ty<'tcx> {
-        self.mk_ty(Infer(it))
+    pub fn mk_fresh_ty(self, n: u32) -> Ty<'tcx> {
+        // Use a pre-interned one when possible.
+        self.types
+            .fresh_tys
+            .get(n as usize)
+            .copied()
+            .unwrap_or_else(|| self.mk_ty(Infer(ty::FreshTy(n))))
+    }
+
+    #[inline]
+    pub fn mk_fresh_int_ty(self, n: u32) -> Ty<'tcx> {
+        // Use a pre-interned one when possible.
+        self.types
+            .fresh_int_tys
+            .get(n as usize)
+            .copied()
+            .unwrap_or_else(|| self.mk_ty(Infer(ty::FreshIntTy(n))))
+    }
+
+    #[inline]
+    pub fn mk_fresh_float_ty(self, n: u32) -> Ty<'tcx> {
+        // Use a pre-interned one when possible.
+        self.types
+            .fresh_float_tys
+            .get(n as usize)
+            .copied()
+            .unwrap_or_else(|| self.mk_ty(Infer(ty::FreshFloatTy(n))))
     }
 
     #[inline]
@@ -1913,8 +1977,23 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     #[inline]
+    pub fn mk_bound(self, index: ty::DebruijnIndex, bound_ty: ty::BoundTy) -> Ty<'tcx> {
+        self.mk_ty(Bound(index, bound_ty))
+    }
+
+    #[inline]
+    pub fn mk_placeholder(self, placeholder: ty::PlaceholderType) -> Ty<'tcx> {
+        self.mk_ty(Placeholder(placeholder))
+    }
+
+    #[inline]
+    pub fn mk_alias(self, kind: ty::AliasKind, alias_ty: ty::AliasTy<'tcx>) -> Ty<'tcx> {
+        self.mk_ty(Alias(kind, alias_ty))
+    }
+
+    #[inline]
     pub fn mk_opaque(self, def_id: DefId, substs: SubstsRef<'tcx>) -> Ty<'tcx> {
-        self.mk_ty(Alias(ty::Opaque, self.mk_alias_ty(def_id, substs)))
+        self.mk_alias(ty::Opaque, self.mk_alias_ty(def_id, substs))
     }
 
     pub fn mk_place_field(self, place: Place<'tcx>, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index 8a0019bc012..c0d319edf76 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -562,10 +562,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     ))
                 },
                 types: &mut |t: ty::BoundTy| {
-                    self.mk_ty(ty::Bound(
-                        ty::INNERMOST,
-                        ty::BoundTy { var: shift_bv(t.var), kind: t.kind },
-                    ))
+                    self.mk_bound(ty::INNERMOST, ty::BoundTy { var: shift_bv(t.var), kind: t.kind })
                 },
                 consts: &mut |c, ty: Ty<'tcx>| {
                     self.mk_const(ty::ConstKind::Bound(ty::INNERMOST, shift_bv(c)), ty)
@@ -614,7 +611,7 @@ impl<'tcx> TyCtxt<'tcx> {
                         ty::BoundVariableKind::Ty(ty::BoundTyKind::Anon(index as u32))
                     })
                     .expect_ty();
-                self.tcx.mk_ty(ty::Bound(ty::INNERMOST, BoundTy { var, kind }))
+                self.tcx.mk_bound(ty::INNERMOST, BoundTy { var, kind })
             }
             fn replace_const(&mut self, bv: ty::BoundVar, ty: Ty<'tcx>) -> ty::Const<'tcx> {
                 let entry = self.map.entry(bv);
@@ -684,7 +681,7 @@ impl<'tcx> TypeFolder<'tcx> for Shifter<'tcx> {
         match *ty.kind() {
             ty::Bound(debruijn, bound_ty) if debruijn >= self.current_index => {
                 let debruijn = debruijn.shifted_in(self.amount);
-                self.tcx.mk_ty(ty::Bound(debruijn, bound_ty))
+                self.tcx.mk_bound(debruijn, bound_ty)
             }
 
             _ if ty.has_vars_bound_at_or_above(self.current_index) => ty.super_fold_with(self),
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index e9a10f483e5..c4a95ddacbf 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -1209,7 +1209,7 @@ pub trait PrettyPrinter<'tcx>:
                 // in order to place the projections inside the `<...>`.
                 if !resugared {
                     // Use a type that can't appear in defaults of type parameters.
-                    let dummy_cx = cx.tcx().mk_ty_infer(ty::FreshTy(0));
+                    let dummy_cx = cx.tcx().mk_fresh_ty(0);
                     let principal = principal.with_self_ty(cx.tcx(), dummy_cx);
 
                     let args = cx
@@ -2696,7 +2696,7 @@ define_print_and_forward_display! {
 
     ty::ExistentialTraitRef<'tcx> {
         // Use a type that can't appear in defaults of type parameters.
-        let dummy_self = cx.tcx().mk_ty_infer(ty::FreshTy(0));
+        let dummy_self = cx.tcx().mk_fresh_ty(0);
         let trait_ref = self.with_self_ty(cx.tcx(), dummy_self);
         p!(print(trait_ref.print_only_trait_path()))
     }
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 890dabde1f7..3b22da41a57 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -502,7 +502,7 @@ pub fn super_relate_tys<'tcx, R: TypeRelation<'tcx>>(
         (&ty::Array(a_t, sz_a), &ty::Array(b_t, sz_b)) => {
             let t = relation.relate(a_t, b_t)?;
             match relation.relate(sz_a, sz_b) {
-                Ok(sz) => Ok(tcx.mk_ty(ty::Array(t, sz))),
+                Ok(sz) => Ok(tcx.mk_array_with_const_len(t, sz)),
                 Err(err) => {
                     // Check whether the lengths are both concrete/known values,
                     // but are unequal, for better diagnostics.
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index b3b2a4fd0e5..89cde91e755 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1171,7 +1171,7 @@ impl<'tcx> FallibleTypeFolder<'tcx> for SkipBindersAt<'tcx> {
             if index == self.index {
                 Err(())
             } else {
-                Ok(self.tcx().mk_ty(ty::Bound(index.shifted_out(1), bv)))
+                Ok(self.tcx().mk_bound(index.shifted_out(1), bv))
             }
         } else {
             ty.try_super_fold_with(self)
@@ -1260,7 +1260,7 @@ impl<'tcx> AliasTy<'tcx> {
     }
 
     pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
-        tcx.mk_ty(ty::Alias(self.kind(tcx), self))
+        tcx.mk_alias(self.kind(tcx), self)
     }
 }
 
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs
index 00d1ff5ceed..c58b6a24ab5 100644
--- a/compiler/rustc_symbol_mangling/src/v0.rs
+++ b/compiler/rustc_symbol_mangling/src/v0.rs
@@ -540,7 +540,7 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
                 match predicate.as_ref().skip_binder() {
                     ty::ExistentialPredicate::Trait(trait_ref) => {
                         // Use a type that can't appear in defaults of type parameters.
-                        let dummy_self = cx.tcx.mk_ty_infer(ty::FreshTy(0));
+                        let dummy_self = cx.tcx.mk_fresh_ty(0);
                         let trait_ref = trait_ref.with_self_ty(cx.tcx, dummy_self);
                         cx = cx.print_def_path(trait_ref.def_id, trait_ref.substs)?;
                     }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 048a5471994..cca178299df 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -3572,7 +3572,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                 {
                     type_diffs = vec![
                         Sorts(ty::error::ExpectedFound {
-                            expected: self.tcx.mk_ty(ty::Alias(ty::Projection, where_pred.skip_binder().projection_ty)),
+                            expected: self.tcx.mk_alias(ty::Projection, where_pred.skip_binder().projection_ty),
                             found,
                         }),
                     ];
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index aa81bc640aa..c2bce774bb5 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -785,7 +785,7 @@ impl<'tcx> TypeFolder<'tcx> for BoundVarReplacer<'_, 'tcx> {
                 let universe = self.universe_for(debruijn);
                 let p = ty::PlaceholderType { universe, name: bound_ty.kind };
                 self.mapped_types.insert(p, bound_ty);
-                self.infcx.tcx.mk_ty(ty::Placeholder(p))
+                self.infcx.tcx.mk_placeholder(p)
             }
             _ if t.has_vars_bound_at_or_above(self.current_index) => t.super_fold_with(self),
             _ => t,
@@ -915,7 +915,7 @@ impl<'tcx> TypeFolder<'tcx> for PlaceholderReplacer<'_, 'tcx> {
                         let db = ty::DebruijnIndex::from_usize(
                             self.universe_indices.len() - index + self.current_index.as_usize() - 1,
                         );
-                        self.tcx().mk_ty(ty::Bound(db, *replace_var))
+                        self.tcx().mk_bound(db, *replace_var)
                     }
                     None => ty,
                 }
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index fcc4820c2a6..dc5bcb48cad 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -527,13 +527,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                                 let kind = ty::BoundTyKind::Param(param.def_id, param.name);
                                 let bound_var = ty::BoundVariableKind::Ty(kind);
                                 bound_vars.push(bound_var);
-                                tcx.mk_ty(ty::Bound(
+                                tcx.mk_bound(
                                     ty::INNERMOST,
                                     ty::BoundTy {
                                         var: ty::BoundVar::from_usize(bound_vars.len() - 1),
                                         kind,
                                     },
-                                ))
+                                )
                                 .into()
                             }
                             GenericParamDefKind::Lifetime => {
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index 1136b70a0b9..5cfb6cf332e 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -879,7 +879,7 @@ pub fn object_region_bounds<'tcx>(
     // Since we don't actually *know* the self type for an object,
     // this "open(err)" serves as a kind of dummy standin -- basically
     // a placeholder type.
-    let open_ty = tcx.mk_ty_infer(ty::FreshTy(0));
+    let open_ty = tcx.mk_fresh_ty(0);
 
     let predicates = existential_predicates.iter().filter_map(|predicate| {
         if let ty::ExistentialPredicate::Projection(_) = predicate.skip_binder() {
diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
index dbd5f13fe4e..7101f404269 100644
--- a/compiler/rustc_traits/src/chalk/db.rs
+++ b/compiler/rustc_traits/src/chalk/db.rs
@@ -588,10 +588,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
         _id: chalk_ir::OpaqueTyId<RustInterner<'tcx>>,
     ) -> chalk_ir::Ty<RustInterner<'tcx>> {
         // FIXME(chalk): actually get hidden ty
-        self.interner
-            .tcx
-            .mk_ty(ty::Tuple(self.interner.tcx.intern_type_list(&[])))
-            .lower_into(self.interner)
+        self.interner.tcx.types.unit.lower_into(self.interner)
     }
 
     fn closure_kind(
@@ -721,13 +718,13 @@ impl<'tcx> chalk_ir::UnificationDatabase<RustInterner<'tcx>> for RustIrDatabase<
 fn bound_vars_for_item(tcx: TyCtxt<'_>, def_id: DefId) -> SubstsRef<'_> {
     InternalSubsts::for_item(tcx, def_id, |param, substs| match param.kind {
         ty::GenericParamDefKind::Type { .. } => tcx
-            .mk_ty(ty::Bound(
+            .mk_bound(
                 ty::INNERMOST,
                 ty::BoundTy {
                     var: ty::BoundVar::from(param.index),
                     kind: ty::BoundTyKind::Param(param.def_id, param.name),
                 },
-            ))
+            )
             .into(),
 
         ty::GenericParamDefKind::Lifetime => {
@@ -790,10 +787,9 @@ impl<'tcx> ty::TypeFolder<'tcx> for ReplaceOpaqueTyFolder<'tcx> {
     fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
         if let ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) = *ty.kind() {
             if def_id == self.opaque_ty_id.0 && substs == self.identity_substs {
-                return self.tcx.mk_ty(ty::Bound(
-                    self.binder_index,
-                    ty::BoundTy::from(ty::BoundVar::from_u32(0)),
-                ));
+                return self
+                    .tcx
+                    .mk_bound(self.binder_index, ty::BoundTy::from(ty::BoundVar::from_u32(0)));
             }
         }
         ty
diff --git a/compiler/rustc_traits/src/chalk/lowering.rs b/compiler/rustc_traits/src/chalk/lowering.rs
index 7c9a014e2ab..4f71dcde818 100644
--- a/compiler/rustc_traits/src/chalk/lowering.rs
+++ b/compiler/rustc_traits/src/chalk/lowering.rs
@@ -677,11 +677,11 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::Binders<chalk_ir::QuantifiedWhereClauses<Ru
         // shifted in by one so that they are still escaping.
         let predicates = ty::fold::shift_vars(interner.tcx, self, 1);
 
-        let self_ty = interner.tcx.mk_ty(ty::Bound(
+        let self_ty = interner.tcx.mk_bound(
             // This is going to be wrapped in a binder
             ty::DebruijnIndex::from_usize(1),
             ty::BoundTy { var: ty::BoundVar::from_usize(0), kind: ty::BoundTyKind::Anon(0) },
-        ));
+        );
         let where_clauses = predicates.into_iter().map(|predicate| {
             let (predicate, binders, _named_regions) =
                 collect_bound_vars(interner, interner.tcx, predicate);
@@ -1077,18 +1077,18 @@ impl<'tcx> TypeFolder<'tcx> for ParamsSubstitutor<'tcx> {
     fn fold_ty(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
         match *t.kind() {
             ty::Param(param) => match self.list.iter().position(|r| r == &param) {
-                Some(idx) => self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
+                Some(idx) => self.tcx.mk_placeholder(ty::PlaceholderType {
                     universe: ty::UniverseIndex::from_usize(0),
                     name: ty::BoundTyKind::Anon(idx as u32),
-                })),
+                }),
                 None => {
                     self.list.push(param);
                     let idx = self.list.len() - 1 + self.next_ty_placeholder;
                     self.params.insert(idx as u32, param);
-                    self.tcx.mk_ty(ty::Placeholder(ty::PlaceholderType {
+                    self.tcx.mk_placeholder(ty::PlaceholderType {
                         universe: ty::UniverseIndex::from_usize(0),
                         name: ty::BoundTyKind::Anon(idx as u32),
-                    }))
+                    })
                 }
             },
             _ => t.super_fold_with(self),
@@ -1147,7 +1147,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseParamsSubstitutor<'tcx> {
         match *t.kind() {
             ty::Placeholder(ty::PlaceholderType { universe: ty::UniverseIndex::ROOT, name }) => {
                 match self.params.get(&name.expect_anon()) {
-                    Some(param) => self.tcx.mk_ty(ty::Param(*param)),
+                    Some(&ty::ParamTy { index, name }) => self.tcx.mk_ty_param(index, name),
                     None => t,
                 }
             }
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 779cbaa6802..0e2191185eb 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -516,27 +516,27 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
         // FIXME: Only simple types are supported here, see if we can support
         // other types such as Tuple, Array, Slice, etc.
         // See https://github.com/rust-lang/rust/issues/90703#issuecomment-1004263455
-        Some(tcx.mk_ty(match prim {
-            Bool => ty::Bool,
-            Str => ty::Str,
-            Char => ty::Char,
-            Never => ty::Never,
-            I8 => ty::Int(ty::IntTy::I8),
-            I16 => ty::Int(ty::IntTy::I16),
-            I32 => ty::Int(ty::IntTy::I32),
-            I64 => ty::Int(ty::IntTy::I64),
-            I128 => ty::Int(ty::IntTy::I128),
-            Isize => ty::Int(ty::IntTy::Isize),
-            F32 => ty::Float(ty::FloatTy::F32),
-            F64 => ty::Float(ty::FloatTy::F64),
-            U8 => ty::Uint(ty::UintTy::U8),
-            U16 => ty::Uint(ty::UintTy::U16),
-            U32 => ty::Uint(ty::UintTy::U32),
-            U64 => ty::Uint(ty::UintTy::U64),
-            U128 => ty::Uint(ty::UintTy::U128),
-            Usize => ty::Uint(ty::UintTy::Usize),
+        Some(match prim {
+            Bool => tcx.types.bool,
+            Str => tcx.types.str_,
+            Char => tcx.types.char,
+            Never => tcx.types.never,
+            I8 => tcx.types.i8,
+            I16 => tcx.types.i16,
+            I32 => tcx.types.i32,
+            I64 => tcx.types.i64,
+            I128 => tcx.types.i128,
+            Isize => tcx.types.isize,
+            F32 => tcx.types.f32,
+            F64 => tcx.types.f64,
+            U8 => tcx.types.u8,
+            U16 => tcx.types.u16,
+            U32 => tcx.types.u32,
+            U64 => tcx.types.u64,
+            U128 => tcx.types.u128,
+            Usize => tcx.types.usize,
             _ => return None,
-        }))
+        })
     }
 
     /// Resolve an associated item, returning its containing page's `Res`