From c9c4053eed8ec7cfc66bf51743cdc144abd593f6 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sat, 6 Jan 2024 16:58:15 +0100
Subject: [PATCH 1/3] More aliases

---
 crates/hir-ty/src/interner.rs | 232 +++++++++++++++++-----------------
 crates/hir-ty/src/lib.rs      |  13 +-
 2 files changed, 130 insertions(+), 115 deletions(-)

diff --git a/crates/hir-ty/src/interner.rs b/crates/hir-ty/src/interner.rs
index e4dd4b86cf99..7d3539edad1c 100644
--- a/crates/hir-ty/src/interner.rs
+++ b/crates/hir-ty/src/interner.rs
@@ -1,9 +1,15 @@
 //! Implementation of the Chalk `Interner` trait, which allows customizing the
 //! representation of the various objects Chalk deals with (types, goals etc.).
 
-use crate::{chalk_db, tls, ConstScalar, GenericArg};
+use crate::{
+    chalk_db, tls, AliasTy, CanonicalVarKind, CanonicalVarKinds, ClosureId, Const, ConstData,
+    ConstScalar, Constraint, Constraints, FnDefId, GenericArg, GenericArgData, Goal, GoalData,
+    Goals, InEnvironment, Lifetime, LifetimeData, OpaqueTy, OpaqueTyId, ProgramClause,
+    ProgramClauseData, ProgramClauses, ProjectionTy, QuantifiedWhereClause, QuantifiedWhereClauses,
+    Substitution, Ty, TyData, TyKind, VariableKind, VariableKinds,
+};
 use base_db::salsa::InternId;
-use chalk_ir::{Goal, GoalData};
+use chalk_ir::{ProgramClauseImplication, SeparatorTraitRef, Variance};
 use hir_def::TypeAliasId;
 use intern::{impl_internable, Interned};
 use smallvec::SmallVec;
@@ -30,37 +36,70 @@ impl<T> std::ops::Deref for InternedWrapper<T> {
     }
 }
 
+#[derive(Eq)]
+pub struct PreHashedWrapper<T>(T, u64);
+
+impl<T: fmt::Debug> fmt::Debug for PreHashedWrapper<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&self.0, f)
+    }
+}
+
+impl<T: PartialEq> PartialEq for PreHashedWrapper<T> {
+    fn eq(&self, other: &Self) -> bool {
+        self.1 == other.1 && self.0 == other.0
+    }
+}
+
+impl<T> std::ops::Deref for PreHashedWrapper<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<T: std::hash::Hash> std::hash::Hash for PreHashedWrapper<T> {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        state.write_u64(self.1);
+    }
+}
+
 impl_internable!(
-    InternedWrapper<Vec<chalk_ir::VariableKind<Interner>>>,
+    InternedWrapper<Vec<VariableKind>>,
     InternedWrapper<SmallVec<[GenericArg; 2]>>,
-    InternedWrapper<chalk_ir::TyData<Interner>>,
-    InternedWrapper<chalk_ir::LifetimeData<Interner>>,
-    InternedWrapper<chalk_ir::ConstData<Interner>>,
+    InternedWrapper<TyData>,
+    InternedWrapper<LifetimeData>,
+    InternedWrapper<ConstData>,
     InternedWrapper<ConstScalar>,
-    InternedWrapper<Vec<chalk_ir::CanonicalVarKind<Interner>>>,
-    InternedWrapper<Vec<chalk_ir::ProgramClause<Interner>>>,
-    InternedWrapper<Vec<chalk_ir::QuantifiedWhereClause<Interner>>>,
-    InternedWrapper<Vec<chalk_ir::Variance>>,
+    InternedWrapper<Vec<CanonicalVarKind>>,
+    InternedWrapper<Vec<ProgramClause>>,
+    InternedWrapper<Vec<QuantifiedWhereClause>>,
+    InternedWrapper<SmallVec<[Variance; 16]>>,
+    // InternedWrapper<PreHashedWrapper<Goals>>,
 );
 
 impl chalk_ir::interner::Interner for Interner {
-    type InternedType = Interned<InternedWrapper<chalk_ir::TyData<Self>>>;
-    type InternedLifetime = Interned<InternedWrapper<chalk_ir::LifetimeData<Self>>>;
-    type InternedConst = Interned<InternedWrapper<chalk_ir::ConstData<Self>>>;
+    type InternedType = Interned<InternedWrapper<TyData>>;
+    type InternedLifetime = Interned<InternedWrapper<LifetimeData>>;
+    type InternedConst = Interned<InternedWrapper<ConstData>>;
     type InternedConcreteConst = ConstScalar;
-    type InternedGenericArg = chalk_ir::GenericArgData<Self>;
-    type InternedGoal = Arc<GoalData<Self>>;
-    type InternedGoals = Vec<Goal<Self>>;
+    type InternedGenericArg = GenericArgData;
+    // We could do the following, but that saves "only" 20mb on self while increasing inferecene
+    // time by ~2.5%
+    // type InternedGoal = Interned<InternedWrapper<GoalData>>;
+    // type InternedGoal = Interned<InternedWrapper<PreHashedWrapper<GoalData>>>;
+    type InternedGoal = Arc<GoalData>;
+    type InternedGoals = Vec<Goal>;
     type InternedSubstitution = Interned<InternedWrapper<SmallVec<[GenericArg; 2]>>>;
-    type InternedProgramClauses = Interned<InternedWrapper<Vec<chalk_ir::ProgramClause<Self>>>>;
-    type InternedProgramClause = chalk_ir::ProgramClauseData<Self>;
-    type InternedQuantifiedWhereClauses =
-        Interned<InternedWrapper<Vec<chalk_ir::QuantifiedWhereClause<Self>>>>;
-    type InternedVariableKinds = Interned<InternedWrapper<Vec<chalk_ir::VariableKind<Interner>>>>;
-    type InternedCanonicalVarKinds =
-        Interned<InternedWrapper<Vec<chalk_ir::CanonicalVarKind<Self>>>>;
-    type InternedConstraints = Vec<chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>>;
-    type InternedVariances = Interned<InternedWrapper<Vec<chalk_ir::Variance>>>;
+    type InternedProgramClauses = Interned<InternedWrapper<Vec<ProgramClause>>>;
+    type InternedProgramClause = ProgramClauseData;
+    type InternedQuantifiedWhereClauses = Interned<InternedWrapper<Vec<QuantifiedWhereClause>>>;
+    type InternedVariableKinds = Interned<InternedWrapper<Vec<VariableKind>>>;
+    type InternedCanonicalVarKinds = Interned<InternedWrapper<Vec<CanonicalVarKind>>>;
+    // type InternedConstraints = SmallVec<[InEnvironment<Constraint>; 1]>;
+    type InternedConstraints = Vec<InEnvironment<Constraint>>;
+    type InternedVariances = SmallVec<[Variance; 16]>;
     type DefId = InternId;
     type InternedAdtId = hir_def::AdtId;
     type Identifier = TypeAliasId;
@@ -88,68 +127,51 @@ impl chalk_ir::interner::Interner for Interner {
     }
 
     fn debug_opaque_ty_id(
-        opaque_ty_id: chalk_ir::OpaqueTyId<Self>,
+        opaque_ty_id: OpaqueTyId,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "OpaqueTy#{}", opaque_ty_id.0))
     }
 
-    fn debug_fn_def_id(
-        fn_def_id: chalk_ir::FnDefId<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_fn_def_id(fn_def_id: FnDefId, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_fn_def_id(fn_def_id, fmt)))
     }
 
     fn debug_closure_id(
-        _fn_def_id: chalk_ir::ClosureId<Self>,
+        _fn_def_id: ClosureId,
         _fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         None
     }
 
-    fn debug_alias(
-        alias: &chalk_ir::AliasTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_alias(alias: &AliasTy, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         use std::fmt::Debug;
         match alias {
-            chalk_ir::AliasTy::Projection(projection_ty) => {
-                Interner::debug_projection_ty(projection_ty, fmt)
-            }
-            chalk_ir::AliasTy::Opaque(opaque_ty) => Some(opaque_ty.fmt(fmt)),
+            AliasTy::Projection(projection_ty) => Interner::debug_projection_ty(projection_ty, fmt),
+            AliasTy::Opaque(opaque_ty) => Some(opaque_ty.fmt(fmt)),
         }
     }
 
     fn debug_projection_ty(
-        proj: &chalk_ir::ProjectionTy<Interner>,
+        proj: &ProjectionTy,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         tls::with_current_program(|prog| Some(prog?.debug_projection_ty(proj, fmt)))
     }
 
-    fn debug_opaque_ty(
-        opaque_ty: &chalk_ir::OpaqueTy<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_opaque_ty(opaque_ty: &OpaqueTy, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", opaque_ty.opaque_ty_id))
     }
 
-    fn debug_ty(ty: &chalk_ir::Ty<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_ty(ty: &Ty, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", ty.data(Interner)))
     }
 
-    fn debug_lifetime(
-        lifetime: &chalk_ir::Lifetime<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_lifetime(lifetime: &Lifetime, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", lifetime.data(Interner)))
     }
 
-    fn debug_const(
-        constant: &chalk_ir::Const<Self>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_const(constant: &Const, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", constant.data(Interner)))
     }
 
@@ -161,102 +183,99 @@ impl chalk_ir::interner::Interner for Interner {
     }
 
     fn debug_variable_kinds(
-        variable_kinds: &chalk_ir::VariableKinds<Self>,
+        variable_kinds: &VariableKinds,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", variable_kinds.as_slice(Interner)))
     }
 
     fn debug_variable_kinds_with_angles(
-        variable_kinds: &chalk_ir::VariableKinds<Self>,
+        variable_kinds: &VariableKinds,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", variable_kinds.inner_debug(Interner)))
     }
 
     fn debug_canonical_var_kinds(
-        canonical_var_kinds: &chalk_ir::CanonicalVarKinds<Self>,
+        canonical_var_kinds: &CanonicalVarKinds,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", canonical_var_kinds.as_slice(Interner)))
     }
-    fn debug_goal(goal: &Goal<Interner>, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
+    fn debug_goal(goal: &Goal, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         let goal_data = goal.data(Interner);
         Some(write!(fmt, "{goal_data:?}"))
     }
-    fn debug_goals(
-        goals: &chalk_ir::Goals<Interner>,
-        fmt: &mut fmt::Formatter<'_>,
-    ) -> Option<fmt::Result> {
+    fn debug_goals(goals: &Goals, fmt: &mut fmt::Formatter<'_>) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", goals.debug(Interner)))
     }
     fn debug_program_clause_implication(
-        pci: &chalk_ir::ProgramClauseImplication<Interner>,
+        pci: &ProgramClauseImplication<Self>,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", pci.debug(Interner)))
     }
     fn debug_program_clause(
-        clause: &chalk_ir::ProgramClause<Self>,
+        clause: &ProgramClause,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", clause.data(Interner)))
     }
     fn debug_program_clauses(
-        clauses: &chalk_ir::ProgramClauses<Self>,
+        clauses: &ProgramClauses,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", clauses.as_slice(Interner)))
     }
     fn debug_substitution(
-        substitution: &chalk_ir::Substitution<Interner>,
+        substitution: &Substitution,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", substitution.debug(Interner)))
     }
     fn debug_separator_trait_ref(
-        separator_trait_ref: &chalk_ir::SeparatorTraitRef<'_, Interner>,
+        separator_trait_ref: &SeparatorTraitRef<'_, Interner>,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", separator_trait_ref.debug(Interner)))
     }
 
     fn debug_quantified_where_clauses(
-        clauses: &chalk_ir::QuantifiedWhereClauses<Self>,
+        clauses: &QuantifiedWhereClauses,
         fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         Some(write!(fmt, "{:?}", clauses.as_slice(Interner)))
     }
 
     fn debug_constraints(
-        _clauses: &chalk_ir::Constraints<Self>,
+        _clauses: &Constraints,
         _fmt: &mut fmt::Formatter<'_>,
     ) -> Option<fmt::Result> {
         None
     }
 
-    fn intern_ty(self, kind: chalk_ir::TyKind<Self>) -> Self::InternedType {
+    fn intern_ty(self, kind: TyKind) -> Self::InternedType {
         let flags = kind.compute_flags(self);
-        Interned::new(InternedWrapper(chalk_ir::TyData { kind, flags }))
+        Interned::new(InternedWrapper(TyData { kind, flags }))
     }
 
-    fn ty_data(self, ty: &Self::InternedType) -> &chalk_ir::TyData<Self> {
+    fn ty_data(self, ty: &Self::InternedType) -> &TyData {
         &ty.0
     }
 
-    fn intern_lifetime(self, lifetime: chalk_ir::LifetimeData<Self>) -> Self::InternedLifetime {
+    fn intern_lifetime(self, lifetime: LifetimeData) -> Self::InternedLifetime {
         Interned::new(InternedWrapper(lifetime))
     }
 
-    fn lifetime_data(self, lifetime: &Self::InternedLifetime) -> &chalk_ir::LifetimeData<Self> {
+    fn lifetime_data(self, lifetime: &Self::InternedLifetime) -> &LifetimeData {
         &lifetime.0
     }
 
-    fn intern_const(self, constant: chalk_ir::ConstData<Self>) -> Self::InternedConst {
+    fn intern_const(self, constant: ConstData) -> Self::InternedConst {
         Interned::new(InternedWrapper(constant))
     }
 
-    fn const_data(self, constant: &Self::InternedConst) -> &chalk_ir::ConstData<Self> {
+    fn const_data(self, constant: &Self::InternedConst) -> &ConstData {
         &constant.0
     }
 
@@ -269,36 +288,33 @@ impl chalk_ir::interner::Interner for Interner {
         !matches!(c1, ConstScalar::Bytes(..)) || !matches!(c2, ConstScalar::Bytes(..)) || (c1 == c2)
     }
 
-    fn intern_generic_arg(
-        self,
-        parameter: chalk_ir::GenericArgData<Self>,
-    ) -> Self::InternedGenericArg {
+    fn intern_generic_arg(self, parameter: GenericArgData) -> Self::InternedGenericArg {
         parameter
     }
 
-    fn generic_arg_data(
-        self,
-        parameter: &Self::InternedGenericArg,
-    ) -> &chalk_ir::GenericArgData<Self> {
+    fn generic_arg_data(self, parameter: &Self::InternedGenericArg) -> &GenericArgData {
         parameter
     }
 
-    fn intern_goal(self, goal: GoalData<Self>) -> Self::InternedGoal {
+    fn intern_goal(self, goal: GoalData) -> Self::InternedGoal {
         Arc::new(goal)
     }
 
-    fn goal_data(self, goal: &Self::InternedGoal) -> &GoalData<Self> {
+    fn goal_data(self, goal: &Self::InternedGoal) -> &GoalData {
         goal
     }
 
     fn intern_goals<E>(
         self,
-        data: impl IntoIterator<Item = Result<Goal<Self>, E>>,
+        data: impl IntoIterator<Item = Result<Goal, E>>,
     ) -> Result<Self::InternedGoals, E> {
+        // let hash =
+        //     std::hash::BuildHasher::hash_one(&BuildHasherDefault::<FxHasher>::default(), &goal);
+        // Interned::new(InternedWrapper(PreHashedWrapper(goal, hash)))
         data.into_iter().collect()
     }
 
-    fn goals_data(self, goals: &Self::InternedGoals) -> &[Goal<Interner>] {
+    fn goals_data(self, goals: &Self::InternedGoals) -> &[Goal] {
         goals
     }
 
@@ -313,37 +329,28 @@ impl chalk_ir::interner::Interner for Interner {
         &substitution.as_ref().0
     }
 
-    fn intern_program_clause(
-        self,
-        data: chalk_ir::ProgramClauseData<Self>,
-    ) -> Self::InternedProgramClause {
+    fn intern_program_clause(self, data: ProgramClauseData) -> Self::InternedProgramClause {
         data
     }
 
-    fn program_clause_data(
-        self,
-        clause: &Self::InternedProgramClause,
-    ) -> &chalk_ir::ProgramClauseData<Self> {
+    fn program_clause_data(self, clause: &Self::InternedProgramClause) -> &ProgramClauseData {
         clause
     }
 
     fn intern_program_clauses<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::ProgramClause<Self>, E>>,
+        data: impl IntoIterator<Item = Result<ProgramClause, E>>,
     ) -> Result<Self::InternedProgramClauses, E> {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn program_clauses_data(
-        self,
-        clauses: &Self::InternedProgramClauses,
-    ) -> &[chalk_ir::ProgramClause<Self>] {
+    fn program_clauses_data(self, clauses: &Self::InternedProgramClauses) -> &[ProgramClause] {
         clauses
     }
 
     fn intern_quantified_where_clauses<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::QuantifiedWhereClause<Self>, E>>,
+        data: impl IntoIterator<Item = Result<QuantifiedWhereClause, E>>,
     ) -> Result<Self::InternedQuantifiedWhereClauses, E> {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
@@ -351,27 +358,24 @@ impl chalk_ir::interner::Interner for Interner {
     fn quantified_where_clauses_data(
         self,
         clauses: &Self::InternedQuantifiedWhereClauses,
-    ) -> &[chalk_ir::QuantifiedWhereClause<Self>] {
+    ) -> &[QuantifiedWhereClause] {
         clauses
     }
 
     fn intern_generic_arg_kinds<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::VariableKind<Self>, E>>,
+        data: impl IntoIterator<Item = Result<VariableKind, E>>,
     ) -> Result<Self::InternedVariableKinds, E> {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
 
-    fn variable_kinds_data(
-        self,
-        parameter_kinds: &Self::InternedVariableKinds,
-    ) -> &[chalk_ir::VariableKind<Self>] {
+    fn variable_kinds_data(self, parameter_kinds: &Self::InternedVariableKinds) -> &[VariableKind] {
         &parameter_kinds.as_ref().0
     }
 
     fn intern_canonical_var_kinds<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::CanonicalVarKind<Self>, E>>,
+        data: impl IntoIterator<Item = Result<CanonicalVarKind, E>>,
     ) -> Result<Self::InternedCanonicalVarKinds, E> {
         Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
     }
@@ -379,30 +383,30 @@ impl chalk_ir::interner::Interner for Interner {
     fn canonical_var_kinds_data(
         self,
         canonical_var_kinds: &Self::InternedCanonicalVarKinds,
-    ) -> &[chalk_ir::CanonicalVarKind<Self>] {
+    ) -> &[CanonicalVarKind] {
         canonical_var_kinds
     }
     fn intern_constraints<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>, E>>,
+        data: impl IntoIterator<Item = Result<InEnvironment<Constraint>, E>>,
     ) -> Result<Self::InternedConstraints, E> {
         data.into_iter().collect()
     }
     fn constraints_data(
         self,
         constraints: &Self::InternedConstraints,
-    ) -> &[chalk_ir::InEnvironment<chalk_ir::Constraint<Self>>] {
+    ) -> &[InEnvironment<Constraint>] {
         constraints
     }
 
     fn intern_variances<E>(
         self,
-        data: impl IntoIterator<Item = Result<chalk_ir::Variance, E>>,
+        data: impl IntoIterator<Item = Result<Variance, E>>,
     ) -> Result<Self::InternedVariances, E> {
-        Ok(Interned::new(InternedWrapper(data.into_iter().collect::<Result<_, _>>()?)))
+        data.into_iter().collect::<Result<_, _>>()
     }
 
-    fn variances_data(self, variances: &Self::InternedVariances) -> &[chalk_ir::Variance] {
+    fn variances_data(self, variances: &Self::InternedVariances) -> &[Variance] {
         variances
     }
 }
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index cf174feed24b..b60fbac5af8a 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -45,7 +45,7 @@ use chalk_ir::{
     fold::{Shift, TypeFoldable},
     interner::HasInterner,
     visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor},
-    NoSolution, TyData,
+    NoSolution,
 };
 use either::Either;
 use hir_def::{hir::ExprId, type_ref::Rawness, GeneralConstId, TypeOrConstParamId};
@@ -152,10 +152,21 @@ pub type DomainGoal = chalk_ir::DomainGoal<Interner>;
 pub type Goal = chalk_ir::Goal<Interner>;
 pub type AliasEq = chalk_ir::AliasEq<Interner>;
 pub type Solution = chalk_solve::Solution<Interner>;
+pub type Constraint = chalk_ir::Constraint<Interner>;
+pub type Constraints = chalk_ir::Constraints<Interner>;
 pub type ConstrainedSubst = chalk_ir::ConstrainedSubst<Interner>;
 pub type Guidance = chalk_solve::Guidance<Interner>;
 pub type WhereClause = chalk_ir::WhereClause<Interner>;
 
+pub type CanonicalVarKind = chalk_ir::CanonicalVarKind<Interner>;
+pub type GoalData = chalk_ir::GoalData<Interner>;
+pub type Goals = chalk_ir::Goals<Interner>;
+pub type ProgramClauseData = chalk_ir::ProgramClauseData<Interner>;
+pub type ProgramClause = chalk_ir::ProgramClause<Interner>;
+pub type ProgramClauses = chalk_ir::ProgramClauses<Interner>;
+pub type TyData = chalk_ir::TyData<Interner>;
+pub type Variances = chalk_ir::Variances<Interner>;
+
 /// A constant can have reference to other things. Memory map job is holding
 /// the necessary bits of memory of the const eval session to keep the constant
 /// meaningful.

From 5125063a210ca85a86787c24fb14bebdce766488 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sat, 6 Jan 2024 17:48:07 +0100
Subject: [PATCH 2/3] Remove unnecessary cloning

---
 crates/hir-ty/src/consteval.rs                |  8 +--
 crates/hir-ty/src/lib.rs                      |  2 +-
 crates/hir-ty/src/mir.rs                      |  8 +--
 crates/hir-ty/src/mir/eval.rs                 | 24 ++++----
 crates/hir-ty/src/mir/eval/shim.rs            |  3 +-
 crates/hir-ty/src/mir/lower.rs                | 57 ++++++++++---------
 .../hir-ty/src/mir/lower/pattern_matching.rs  |  2 +-
 7 files changed, 54 insertions(+), 50 deletions(-)

diff --git a/crates/hir-ty/src/consteval.rs b/crates/hir-ty/src/consteval.rs
index 9792d945eb8f..5528ad3ab4ab 100644
--- a/crates/hir-ty/src/consteval.rs
+++ b/crates/hir-ty/src/consteval.rs
@@ -142,15 +142,15 @@ pub fn intern_const_ref(
         LiteralConstRef::Int(i) => {
             // FIXME: We should handle failure of layout better.
             let size = layout.map(|it| it.size.bytes_usize()).unwrap_or(16);
-            ConstScalar::Bytes(i.to_le_bytes()[0..size].to_vec(), MemoryMap::default())
+            ConstScalar::Bytes(i.to_le_bytes()[0..size].into(), MemoryMap::default())
         }
         LiteralConstRef::UInt(i) => {
             let size = layout.map(|it| it.size.bytes_usize()).unwrap_or(16);
-            ConstScalar::Bytes(i.to_le_bytes()[0..size].to_vec(), MemoryMap::default())
+            ConstScalar::Bytes(i.to_le_bytes()[0..size].into(), MemoryMap::default())
         }
-        LiteralConstRef::Bool(b) => ConstScalar::Bytes(vec![*b as u8], MemoryMap::default()),
+        LiteralConstRef::Bool(b) => ConstScalar::Bytes(Box::new([*b as u8]), MemoryMap::default()),
         LiteralConstRef::Char(c) => {
-            ConstScalar::Bytes((*c as u32).to_le_bytes().to_vec(), MemoryMap::default())
+            ConstScalar::Bytes((*c as u32).to_le_bytes().into(), MemoryMap::default())
         }
         LiteralConstRef::Unknown => ConstScalar::Unknown,
     };
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index b60fbac5af8a..964ca7ce940e 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -219,7 +219,7 @@ impl MemoryMap {
 /// A concrete constant value
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ConstScalar {
-    Bytes(Vec<u8>, MemoryMap),
+    Bytes(Box<[u8]>, MemoryMap),
     // FIXME: this is a hack to get around chalk not being able to represent unevaluatable
     // constants
     UnevaluatedConst(GeneralConstId, Substitution),
diff --git a/crates/hir-ty/src/mir.rs b/crates/hir-ty/src/mir.rs
index 20e035c8b2e6..7bef6f0d0f71 100644
--- a/crates/hir-ty/src/mir.rs
+++ b/crates/hir-ty/src/mir.rs
@@ -98,16 +98,16 @@ pub enum Operand {
 }
 
 impl Operand {
-    fn from_concrete_const(data: Vec<u8>, memory_map: MemoryMap, ty: Ty) -> Self {
+    fn from_concrete_const(data: Box<[u8]>, memory_map: MemoryMap, ty: Ty) -> Self {
         Operand::Constant(intern_const_scalar(ConstScalar::Bytes(data, memory_map), ty))
     }
 
-    fn from_bytes(data: Vec<u8>, ty: Ty) -> Self {
+    fn from_bytes(data: Box<[u8]>, ty: Ty) -> Self {
         Operand::from_concrete_const(data, MemoryMap::default(), ty)
     }
 
     fn const_zst(ty: Ty) -> Operand {
-        Self::from_bytes(vec![], ty)
+        Self::from_bytes(Box::default(), ty)
     }
 
     fn from_fn(
@@ -118,7 +118,7 @@ impl Operand {
         let ty =
             chalk_ir::TyKind::FnDef(CallableDefId::FunctionId(func_id).to_chalk(db), generic_args)
                 .intern(Interner);
-        Operand::from_bytes(vec![], ty)
+        Operand::from_bytes(Box::default(), ty)
     }
 }
 
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 95cea46f9ebb..4c06566e7ce0 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -527,14 +527,15 @@ pub fn interpret_mir(
         if evaluator.ptr_size() != std::mem::size_of::<usize>() {
             not_supported!("targets with different pointer size from host");
         }
-        let bytes = evaluator.interpret_mir(body.clone(), None.into_iter())?;
+        let interval = evaluator.interpret_mir(body.clone(), None.into_iter())?;
+        let bytes = interval.get(&evaluator)?;
         let mut memory_map = evaluator.create_memory_map(
-            &bytes,
+            bytes,
             &ty,
             &Locals { ptr: ArenaMap::new(), body, drop_flags: DropFlags::default() },
         )?;
         memory_map.vtable = evaluator.vtable_map.clone();
-        return Ok(intern_const_scalar(ConstScalar::Bytes(bytes, memory_map), ty));
+        return Ok(intern_const_scalar(ConstScalar::Bytes(bytes.into(), memory_map), ty));
     })();
     (
         it,
@@ -803,11 +804,11 @@ impl Evaluator<'_> {
         })
     }
 
-    fn interpret_mir(
-        &mut self,
+    fn interpret_mir<'slf>(
+        &'slf mut self,
         body: Arc<MirBody>,
         args: impl Iterator<Item = IntervalOrOwned>,
-    ) -> Result<Vec<u8>> {
+    ) -> Result<Interval> {
         if let Some(it) = self.stack_depth_limit.checked_sub(1) {
             self.stack_depth_limit = it;
         } else {
@@ -957,7 +958,7 @@ impl Evaluator<'_> {
                 None => {
                     self.code_stack = prev_code_stack;
                     self.stack_depth_limit += 1;
-                    return Ok(return_interval.get(self)?.to_vec());
+                    return Ok(return_interval);
                 }
                 Some(bb) => {
                     // We don't support const promotion, so we can't truncate the stack yet.
@@ -2173,7 +2174,7 @@ impl Evaluator<'_> {
         let arg_bytes = iter::once(Ok(closure_data))
             .chain(args.iter().map(|it| Ok(it.get(&self)?.to_owned())))
             .collect::<Result<Vec<_>>>()?;
-        let bytes = self
+        let interval = self
             .interpret_mir(mir_body, arg_bytes.into_iter().map(IntervalOrOwned::Owned))
             .map_err(|e| {
                 MirEvalError::InFunction(
@@ -2181,7 +2182,7 @@ impl Evaluator<'_> {
                     vec![(Either::Right(closure), span, locals.body.owner)],
                 )
             })?;
-        destination.write_from_bytes(self, &bytes)?;
+        destination.write_from_interval(self, interval)?;
         Ok(None)
     }
 
@@ -2374,7 +2375,7 @@ impl Evaluator<'_> {
                     vec![(Either::Left(def), span, locals.body.owner)],
                 )
             })?;
-            destination.write_from_bytes(self, &result)?;
+            destination.write_from_interval(self, result)?;
             None
         })
     }
@@ -2680,11 +2681,12 @@ pub fn render_const_using_debug_impl(
     ) else {
         not_supported!("std::fmt::format not found");
     };
-    let message_string = evaluator.interpret_mir(
+    let interval = evaluator.interpret_mir(
         db.mir_body(format_fn.into()).map_err(|e| MirEvalError::MirLowerError(format_fn, e))?,
         [IntervalOrOwned::Borrowed(Interval { addr: a3, size: evaluator.ptr_size() * 6 })]
             .into_iter(),
     )?;
+    let message_string = interval.get(&evaluator)?;
     let addr =
         Address::from_bytes(&message_string[evaluator.ptr_size()..2 * evaluator.ptr_size()])?;
     let size = from_bytes!(usize, message_string[2 * evaluator.ptr_size()..]);
diff --git a/crates/hir-ty/src/mir/eval/shim.rs b/crates/hir-ty/src/mir/eval/shim.rs
index 2de99e41659c..ff26a3d0be17 100644
--- a/crates/hir-ty/src/mir/eval/shim.rs
+++ b/crates/hir-ty/src/mir/eval/shim.rs
@@ -322,12 +322,13 @@ impl Evaluator<'_> {
                     let hir_def::resolver::ValueNs::FunctionId(format_fn) = format_fn else {
                         not_supported!("std::fmt::format is not a function")
                     };
-                    let message_string = self.interpret_mir(
+                    let interval = self.interpret_mir(
                         self.db
                             .mir_body(format_fn.into())
                             .map_err(|e| MirEvalError::MirLowerError(format_fn, e))?,
                         args.map(|x| IntervalOrOwned::Owned(x.clone())),
                     )?;
+                    let message_string = interval.get(self)?;
                     let addr =
                         Address::from_bytes(&message_string[self.ptr_size()..2 * self.ptr_size()])?;
                     let size = from_bytes!(usize, message_string[2 * self.ptr_size()..]);
diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index c27c1ff7a2a8..a94da818b622 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -540,7 +540,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                 self.write_bytes_to_place(
                     then_target,
                     place.clone(),
-                    vec![1],
+                    Box::new([1]),
                     TyBuilder::bool(),
                     MirSpan::Unknown,
                 )?;
@@ -548,7 +548,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                     self.write_bytes_to_place(
                         else_target,
                         place,
-                        vec![0],
+                        Box::new([0]),
                         TyBuilder::bool(),
                         MirSpan::Unknown,
                     )?;
@@ -602,7 +602,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                         generic_args,
                     )
                     .intern(Interner);
-                    let func = Operand::from_bytes(vec![], ty);
+                    let func = Operand::from_bytes(Box::default(), ty);
                     return self.lower_call_and_args(
                         func,
                         iter::once(*callee).chain(args.iter().copied()),
@@ -615,7 +615,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                 let callee_ty = self.expr_ty_after_adjustments(*callee);
                 match &callee_ty.kind(Interner) {
                     chalk_ir::TyKind::FnDef(..) => {
-                        let func = Operand::from_bytes(vec![], callee_ty.clone());
+                        let func = Operand::from_bytes(Box::default(), callee_ty.clone());
                         self.lower_call_and_args(
                             func,
                             args.iter().copied(),
@@ -1113,7 +1113,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
                                     Some("start") => lp.take(),
                                     Some("end") => rp.take(),
                                     Some("exhausted") => {
-                                        Some(Operand::from_bytes(vec![0], TyBuilder::bool()))
+                                        Some(Operand::from_bytes(Box::new([0]), TyBuilder::bool()))
                                     }
                                     _ => None,
                                 };
@@ -1395,17 +1395,18 @@ impl<'ctx> MirLowerCtx<'ctx> {
     }
 
     fn lower_literal_to_operand(&mut self, ty: Ty, l: &Literal) -> Result<Operand> {
-        let size = self
-            .db
-            .layout_of_ty(ty.clone(), self.db.trait_environment_for_body(self.owner))?
-            .size
-            .bytes_usize();
-        let bytes = match l {
+        let size = || {
+            self.db
+                .layout_of_ty(ty.clone(), self.db.trait_environment_for_body(self.owner))
+                .map(|it| it.size.bytes_usize())
+        };
+        const USIZE_SIZE: usize = mem::size_of::<usize>();
+        let bytes: Box<[_]> = match l {
             hir_def::hir::Literal::String(b) => {
                 let b = b.as_bytes();
-                let mut data = Vec::with_capacity(mem::size_of::<usize>() * 2);
-                data.extend(0usize.to_le_bytes());
-                data.extend(b.len().to_le_bytes());
+                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
+                data[USIZE_SIZE..].copy_from_slice(&b.len().to_le_bytes());
                 let mut mm = MemoryMap::default();
                 mm.insert(0, b.to_vec());
                 return Ok(Operand::from_concrete_const(data, mm, ty));
@@ -1413,28 +1414,28 @@ impl<'ctx> MirLowerCtx<'ctx> {
             hir_def::hir::Literal::CString(b) => {
                 let bytes = b.iter().copied().chain(iter::once(0)).collect::<Vec<_>>();
 
-                let mut data = Vec::with_capacity(mem::size_of::<usize>() * 2);
-                data.extend(0usize.to_le_bytes());
-                data.extend(bytes.len().to_le_bytes());
+                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
+                data[USIZE_SIZE..].copy_from_slice(&bytes.len().to_le_bytes());
                 let mut mm = MemoryMap::default();
                 mm.insert(0, bytes);
                 return Ok(Operand::from_concrete_const(data, mm, ty));
             }
             hir_def::hir::Literal::ByteString(b) => {
-                let mut data = Vec::with_capacity(mem::size_of::<usize>() * 2);
-                data.extend(0usize.to_le_bytes());
-                data.extend(b.len().to_le_bytes());
+                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
+                data[USIZE_SIZE..].copy_from_slice(&b.len().to_le_bytes());
                 let mut mm = MemoryMap::default();
                 mm.insert(0, b.to_vec());
                 return Ok(Operand::from_concrete_const(data, mm, ty));
             }
-            hir_def::hir::Literal::Char(c) => u32::from(*c).to_le_bytes().into(),
-            hir_def::hir::Literal::Bool(b) => vec![*b as u8],
-            hir_def::hir::Literal::Int(it, _) => it.to_le_bytes()[0..size].into(),
-            hir_def::hir::Literal::Uint(it, _) => it.to_le_bytes()[0..size].into(),
-            hir_def::hir::Literal::Float(f, _) => match size {
-                8 => f.into_f64().to_le_bytes().into(),
-                4 => f.into_f32().to_le_bytes().into(),
+            hir_def::hir::Literal::Char(c) => Box::new(u32::from(*c).to_le_bytes()),
+            hir_def::hir::Literal::Bool(b) => Box::new([*b as u8]),
+            hir_def::hir::Literal::Int(it, _) => Box::from(&it.to_le_bytes()[0..size()?]),
+            hir_def::hir::Literal::Uint(it, _) => Box::from(&it.to_le_bytes()[0..size()?]),
+            hir_def::hir::Literal::Float(f, _) => match size()? {
+                8 => Box::new(f.into_f64().to_le_bytes()),
+                4 => Box::new(f.into_f32().to_le_bytes()),
                 _ => {
                     return Err(MirLowerError::TypeError("float with size other than 4 or 8 bytes"))
                 }
@@ -1483,7 +1484,7 @@ impl<'ctx> MirLowerCtx<'ctx> {
         &mut self,
         prev_block: BasicBlockId,
         place: Place,
-        cv: Vec<u8>,
+        cv: Box<[u8]>,
         ty: Ty,
         span: MirSpan,
     ) -> Result<()> {
diff --git a/crates/hir-ty/src/mir/lower/pattern_matching.rs b/crates/hir-ty/src/mir/lower/pattern_matching.rs
index 97ff65a455d3..98c2e7c63bc1 100644
--- a/crates/hir-ty/src/mir/lower/pattern_matching.rs
+++ b/crates/hir-ty/src/mir/lower/pattern_matching.rs
@@ -244,7 +244,7 @@ impl MirLowerCtx<'_> {
                             );
                         } else {
                             let c = Operand::from_concrete_const(
-                                pattern_len.to_le_bytes().to_vec(),
+                                pattern_len.to_le_bytes().into(),
                                 MemoryMap::default(),
                                 TyBuilder::usize(),
                             );

From 5ac0c143848435c444ffd2a4ce71c4b6a33fca47 Mon Sep 17 00:00:00 2001
From: Lukas Wirth <lukastw97@gmail.com>
Date: Sat, 6 Jan 2024 19:20:13 +0100
Subject: [PATCH 3/3] Remove some vec clones in const-eval

---
 crates/hir-ty/src/display.rs        |   2 +-
 crates/hir-ty/src/infer/closure.rs  |   4 +-
 crates/hir-ty/src/interner.rs       |  32 -------
 crates/hir-ty/src/lib.rs            |  76 ++++++++++-----
 crates/hir-ty/src/mir/eval.rs       | 143 +++++++++++++++++-----------
 crates/hir-ty/src/mir/eval/tests.rs |   4 +-
 crates/hir-ty/src/mir/lower.rs      |  24 ++---
 crates/hir/src/lib.rs               |   4 +-
 8 files changed, 161 insertions(+), 128 deletions(-)

diff --git a/crates/hir-ty/src/display.rs b/crates/hir-ty/src/display.rs
index d81926f7c976..4468b96b7764 100644
--- a/crates/hir-ty/src/display.rs
+++ b/crates/hir-ty/src/display.rs
@@ -515,7 +515,7 @@ fn render_const_scalar(
             TyKind::Dyn(_) => {
                 let addr = usize::from_le_bytes(b[0..b.len() / 2].try_into().unwrap());
                 let ty_id = usize::from_le_bytes(b[b.len() / 2..].try_into().unwrap());
-                let Ok(t) = memory_map.vtable.ty(ty_id) else {
+                let Ok(t) = memory_map.vtable_ty(ty_id) else {
                     return f.write_str("<ty-missing-in-vtable-map>");
                 };
                 let Ok(layout) = f.db.layout_of_ty(t.clone(), trait_env) else {
diff --git a/crates/hir-ty/src/infer/closure.rs b/crates/hir-ty/src/infer/closure.rs
index ac00b00fcd97..8a832b6b9042 100644
--- a/crates/hir-ty/src/infer/closure.rs
+++ b/crates/hir-ty/src/infer/closure.rs
@@ -1,6 +1,6 @@
 //! Inference of closure parameter types based on the closure's expected type.
 
-use std::{cmp, collections::HashMap, convert::Infallible, mem};
+use std::{cmp, convert::Infallible, mem};
 
 use chalk_ir::{
     cast::Cast,
@@ -778,7 +778,7 @@ impl InferenceContext<'_> {
 
     fn minimize_captures(&mut self) {
         self.current_captures.sort_by_key(|it| it.place.projections.len());
-        let mut hash_map = HashMap::<HirPlace, usize>::new();
+        let mut hash_map = FxHashMap::<HirPlace, usize>::default();
         let result = mem::take(&mut self.current_captures);
         for item in result {
             let mut lookup_place = HirPlace { local: item.place.local, projections: vec![] };
diff --git a/crates/hir-ty/src/interner.rs b/crates/hir-ty/src/interner.rs
index 7d3539edad1c..eb6296f7a04a 100644
--- a/crates/hir-ty/src/interner.rs
+++ b/crates/hir-ty/src/interner.rs
@@ -36,35 +36,6 @@ impl<T> std::ops::Deref for InternedWrapper<T> {
     }
 }
 
-#[derive(Eq)]
-pub struct PreHashedWrapper<T>(T, u64);
-
-impl<T: fmt::Debug> fmt::Debug for PreHashedWrapper<T> {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        fmt::Debug::fmt(&self.0, f)
-    }
-}
-
-impl<T: PartialEq> PartialEq for PreHashedWrapper<T> {
-    fn eq(&self, other: &Self) -> bool {
-        self.1 == other.1 && self.0 == other.0
-    }
-}
-
-impl<T> std::ops::Deref for PreHashedWrapper<T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl<T: std::hash::Hash> std::hash::Hash for PreHashedWrapper<T> {
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        state.write_u64(self.1);
-    }
-}
-
 impl_internable!(
     InternedWrapper<Vec<VariableKind>>,
     InternedWrapper<SmallVec<[GenericArg; 2]>>,
@@ -76,7 +47,6 @@ impl_internable!(
     InternedWrapper<Vec<ProgramClause>>,
     InternedWrapper<Vec<QuantifiedWhereClause>>,
     InternedWrapper<SmallVec<[Variance; 16]>>,
-    // InternedWrapper<PreHashedWrapper<Goals>>,
 );
 
 impl chalk_ir::interner::Interner for Interner {
@@ -88,7 +58,6 @@ impl chalk_ir::interner::Interner for Interner {
     // We could do the following, but that saves "only" 20mb on self while increasing inferecene
     // time by ~2.5%
     // type InternedGoal = Interned<InternedWrapper<GoalData>>;
-    // type InternedGoal = Interned<InternedWrapper<PreHashedWrapper<GoalData>>>;
     type InternedGoal = Arc<GoalData>;
     type InternedGoals = Vec<Goal>;
     type InternedSubstitution = Interned<InternedWrapper<SmallVec<[GenericArg; 2]>>>;
@@ -97,7 +66,6 @@ impl chalk_ir::interner::Interner for Interner {
     type InternedQuantifiedWhereClauses = Interned<InternedWrapper<Vec<QuantifiedWhereClause>>>;
     type InternedVariableKinds = Interned<InternedWrapper<Vec<VariableKind>>>;
     type InternedCanonicalVarKinds = Interned<InternedWrapper<Vec<CanonicalVarKind>>>;
-    // type InternedConstraints = SmallVec<[InEnvironment<Constraint>; 1]>;
     type InternedConstraints = Vec<InEnvironment<Constraint>>;
     type InternedVariances = SmallVec<[Variance; 16]>;
     type DefId = InternId;
diff --git a/crates/hir-ty/src/lib.rs b/crates/hir-ty/src/lib.rs
index 964ca7ce940e..793b52b49faa 100644
--- a/crates/hir-ty/src/lib.rs
+++ b/crates/hir-ty/src/lib.rs
@@ -37,8 +37,8 @@ mod tests;
 mod test_db;
 
 use std::{
-    collections::{hash_map::Entry, HashMap},
-    hash::Hash,
+    collections::hash_map::Entry,
+    hash::{BuildHasherDefault, Hash},
 };
 
 use chalk_ir::{
@@ -52,7 +52,7 @@ use hir_def::{hir::ExprId, type_ref::Rawness, GeneralConstId, TypeOrConstParamId
 use hir_expand::name;
 use la_arena::{Arena, Idx};
 use mir::{MirEvalError, VTableMap};
-use rustc_hash::FxHashSet;
+use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::ast::{make, ConstArg};
 use traits::FnTrait;
 use triomphe::Arc;
@@ -171,24 +171,45 @@ pub type Variances = chalk_ir::Variances<Interner>;
 /// the necessary bits of memory of the const eval session to keep the constant
 /// meaningful.
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
-pub struct MemoryMap {
-    pub memory: HashMap<usize, Vec<u8>>,
-    pub vtable: VTableMap,
+pub enum MemoryMap {
+    #[default]
+    Empty,
+    Simple(Box<[u8]>),
+    Complex(Box<ComplexMemoryMap>),
 }
 
-impl MemoryMap {
-    fn insert(&mut self, addr: usize, x: Vec<u8>) {
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
+pub struct ComplexMemoryMap {
+    memory: FxHashMap<usize, Box<[u8]>>,
+    vtable: VTableMap,
+}
+
+impl ComplexMemoryMap {
+    fn insert(&mut self, addr: usize, val: Box<[u8]>) {
         match self.memory.entry(addr) {
             Entry::Occupied(mut e) => {
-                if e.get().len() < x.len() {
-                    e.insert(x);
+                if e.get().len() < val.len() {
+                    e.insert(val);
                 }
             }
             Entry::Vacant(e) => {
-                e.insert(x);
+                e.insert(val);
             }
         }
     }
+}
+
+impl MemoryMap {
+    pub fn vtable_ty(&self, id: usize) -> Result<&Ty, MirEvalError> {
+        match self {
+            MemoryMap::Empty | MemoryMap::Simple(_) => Err(MirEvalError::InvalidVTableId(id)),
+            MemoryMap::Complex(cm) => cm.vtable.ty(id),
+        }
+    }
+
+    fn simple(v: Box<[u8]>) -> Self {
+        MemoryMap::Simple(v)
+    }
 
     /// This functions convert each address by a function `f` which gets the byte intervals and assign an address
     /// to them. It is useful when you want to load a constant with a memory map in a new memory. You can pass an
@@ -196,22 +217,33 @@ impl MemoryMap {
     fn transform_addresses(
         &self,
         mut f: impl FnMut(&[u8], usize) -> Result<usize, MirEvalError>,
-    ) -> Result<HashMap<usize, usize>, MirEvalError> {
-        self.memory
-            .iter()
-            .map(|x| {
-                let addr = *x.0;
-                let align = if addr == 0 { 64 } else { (addr - (addr & (addr - 1))).min(64) };
-                Ok((addr, f(x.1, align)?))
-            })
-            .collect()
+    ) -> Result<FxHashMap<usize, usize>, MirEvalError> {
+        let mut transform = |(addr, val): (&usize, &Box<[u8]>)| {
+            let addr = *addr;
+            let align = if addr == 0 { 64 } else { (addr - (addr & (addr - 1))).min(64) };
+            f(val, align).and_then(|it| Ok((addr, it)))
+        };
+        match self {
+            MemoryMap::Empty => Ok(Default::default()),
+            MemoryMap::Simple(m) => transform((&0, m)).map(|(addr, val)| {
+                let mut map = FxHashMap::with_capacity_and_hasher(1, BuildHasherDefault::default());
+                map.insert(addr, val);
+                map
+            }),
+            MemoryMap::Complex(cm) => cm.memory.iter().map(transform).collect(),
+        }
     }
 
-    fn get<'a>(&'a self, addr: usize, size: usize) -> Option<&'a [u8]> {
+    fn get(&self, addr: usize, size: usize) -> Option<&[u8]> {
         if size == 0 {
             Some(&[])
         } else {
-            self.memory.get(&addr)?.get(0..size)
+            match self {
+                MemoryMap::Empty => Some(&[]),
+                MemoryMap::Simple(m) if addr == 0 => m.get(0..size),
+                MemoryMap::Simple(_) => None,
+                MemoryMap::Complex(cm) => cm.memory.get(&addr)?.get(0..size),
+            }
         }
     }
 }
diff --git a/crates/hir-ty/src/mir/eval.rs b/crates/hir-ty/src/mir/eval.rs
index 4c06566e7ce0..5650956d2f4c 100644
--- a/crates/hir-ty/src/mir/eval.rs
+++ b/crates/hir-ty/src/mir/eval.rs
@@ -1,13 +1,6 @@
 //! This module provides a MIR interpreter, which is used in const eval.
 
-use std::{
-    borrow::Cow,
-    cell::RefCell,
-    collections::{HashMap, HashSet},
-    fmt::Write,
-    iter, mem,
-    ops::Range,
-};
+use std::{borrow::Cow, cell::RefCell, fmt::Write, iter, mem, ops::Range};
 
 use base_db::{CrateId, FileId};
 use chalk_ir::{cast::Cast, Mutability};
@@ -40,8 +33,8 @@ use crate::{
     name, static_lifetime,
     traits::FnTrait,
     utils::{detect_variant_from_bytes, ClosureSubst},
-    CallableDefId, ClosureId, Const, ConstScalar, FnDefId, Interner, MemoryMap, Substitution,
-    TraitEnvironment, Ty, TyBuilder, TyExt, TyKind,
+    CallableDefId, ClosureId, ComplexMemoryMap, Const, ConstScalar, FnDefId, Interner, MemoryMap,
+    Substitution, TraitEnvironment, Ty, TyBuilder, TyExt, TyKind,
 };
 
 use super::{
@@ -98,6 +91,15 @@ impl VTableMap {
         let id = from_bytes!(usize, bytes);
         self.ty(id)
     }
+
+    pub fn shrink_to_fit(&mut self) {
+        self.id_to_ty.shrink_to_fit();
+        self.ty_to_id.shrink_to_fit();
+    }
+
+    fn is_empty(&self) -> bool {
+        self.id_to_ty.is_empty() && self.ty_to_id.is_empty()
+    }
 }
 
 #[derive(Debug, Default, Clone, PartialEq, Eq)]
@@ -251,13 +253,6 @@ impl From<Interval> for IntervalOrOwned {
 }
 
 impl IntervalOrOwned {
-    pub(crate) fn to_vec(self, memory: &Evaluator<'_>) -> Result<Vec<u8>> {
-        Ok(match self {
-            IntervalOrOwned::Owned(o) => o,
-            IntervalOrOwned::Borrowed(b) => b.get(memory)?.to_vec(),
-        })
-    }
-
     fn get<'a>(&'a self, memory: &'a Evaluator<'a>) -> Result<&'a [u8]> {
         Ok(match self {
             IntervalOrOwned::Owned(o) => o,
@@ -291,8 +286,8 @@ impl Address {
         }
     }
 
-    fn to_bytes(&self) -> Vec<u8> {
-        usize::to_le_bytes(self.to_usize()).to_vec()
+    fn to_bytes(&self) -> [u8; mem::size_of::<usize>()] {
+        usize::to_le_bytes(self.to_usize())
     }
 
     fn to_usize(&self) -> usize {
@@ -510,6 +505,20 @@ struct Locals {
     drop_flags: DropFlags,
 }
 
+pub struct MirOutput {
+    stdout: Vec<u8>,
+    stderr: Vec<u8>,
+}
+
+impl MirOutput {
+    pub fn stdout(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(&self.stdout)
+    }
+    pub fn stderr(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(&self.stderr)
+    }
+}
+
 pub fn interpret_mir(
     db: &dyn HirDatabase,
     body: Arc<MirBody>,
@@ -520,7 +529,7 @@ pub fn interpret_mir(
     // (and probably should) do better here, for example by excluding bindings outside of the target expression.
     assert_placeholder_ty_is_unused: bool,
     trait_env: Option<Arc<TraitEnvironment>>,
-) -> (Result<Const>, String, String) {
+) -> (Result<Const>, MirOutput) {
     let ty = body.locals[return_slot()].ty.clone();
     let mut evaluator = Evaluator::new(db, body.owner, assert_placeholder_ty_is_unused, trait_env);
     let it: Result<Const> = (|| {
@@ -534,14 +543,17 @@ pub fn interpret_mir(
             &ty,
             &Locals { ptr: ArenaMap::new(), body, drop_flags: DropFlags::default() },
         )?;
-        memory_map.vtable = evaluator.vtable_map.clone();
-        return Ok(intern_const_scalar(ConstScalar::Bytes(bytes.into(), memory_map), ty));
+        let bytes = bytes.into();
+        let memory_map = if memory_map.memory.is_empty() && evaluator.vtable_map.is_empty() {
+            MemoryMap::Empty
+        } else {
+            memory_map.vtable = mem::take(&mut evaluator.vtable_map);
+            memory_map.vtable.shrink_to_fit();
+            MemoryMap::Complex(Box::new(memory_map))
+        };
+        return Ok(intern_const_scalar(ConstScalar::Bytes(bytes, memory_map), ty));
     })();
-    (
-        it,
-        String::from_utf8_lossy(&evaluator.stdout).into_owned(),
-        String::from_utf8_lossy(&evaluator.stderr).into_owned(),
-    )
+    (it, MirOutput { stdout: evaluator.stdout, stderr: evaluator.stderr })
 }
 
 #[cfg(test)]
@@ -563,7 +575,7 @@ impl Evaluator<'_> {
             code_stack: vec![],
             vtable_map: VTableMap::default(),
             thread_local_storage: TlsData::default(),
-            static_locations: HashMap::default(),
+            static_locations: Default::default(),
             db,
             random_state: oorandom::Rand64::new(0),
             trait_env: trait_env.unwrap_or_else(|| db.trait_environment_for_body(owner)),
@@ -574,11 +586,11 @@ impl Evaluator<'_> {
             stack_depth_limit: 100,
             execution_limit: EXECUTION_LIMIT,
             memory_limit: 1000_000_000, // 2GB, 1GB for stack and 1GB for heap
-            layout_cache: RefCell::new(HashMap::default()),
-            projected_ty_cache: RefCell::new(HashMap::default()),
-            not_special_fn_cache: RefCell::new(HashSet::default()),
-            mir_or_dyn_index_cache: RefCell::new(HashMap::default()),
-            unused_locals_store: RefCell::new(HashMap::default()),
+            layout_cache: RefCell::new(Default::default()),
+            projected_ty_cache: RefCell::new(Default::default()),
+            not_special_fn_cache: RefCell::new(Default::default()),
+            mir_or_dyn_index_cache: RefCell::new(Default::default()),
+            unused_locals_store: RefCell::new(Default::default()),
             cached_ptr_size: match db.target_data_layout(crate_id) {
                 Some(it) => it.pointer_size.bytes_usize(),
                 None => 8,
@@ -838,8 +850,8 @@ impl Evaluator<'_> {
                         match &statement.kind {
                             StatementKind::Assign(l, r) => {
                                 let addr = self.place_addr(l, &locals)?;
-                                let result = self.eval_rvalue(r, &mut locals)?.to_vec(&self)?;
-                                self.write_memory(addr, &result)?;
+                                let result = self.eval_rvalue(r, &mut locals)?;
+                                self.copy_from_interval_or_owned(addr, result)?;
                                 locals
                                     .drop_flags
                                     .add_place(l.clone(), &locals.body.projection_store);
@@ -1051,7 +1063,7 @@ impl Evaluator<'_> {
             Rvalue::Use(it) => Borrowed(self.eval_operand(it, locals)?),
             Rvalue::Ref(_, p) => {
                 let (addr, _, metadata) = self.place_addr_and_ty_and_metadata(p, locals)?;
-                let mut r = addr.to_bytes();
+                let mut r = addr.to_bytes().to_vec();
                 if let Some(metadata) = metadata {
                     r.extend(metadata.get(self)?);
                 }
@@ -1284,7 +1296,7 @@ impl Evaluator<'_> {
                     not_supported!("unsized box initialization");
                 };
                 let addr = self.heap_allocate(size, align)?;
-                Owned(addr.to_bytes())
+                Owned(addr.to_bytes().to_vec())
             }
             Rvalue::CopyForDeref(_) => not_supported!("copy for deref"),
             Rvalue::Aggregate(kind, values) => {
@@ -1716,7 +1728,18 @@ impl Evaluator<'_> {
         }
         let addr = self.heap_allocate(size, align)?;
         self.write_memory(addr, &v)?;
-        self.patch_addresses(&patch_map, &memory_map.vtable, addr, ty, locals)?;
+        self.patch_addresses(
+            &patch_map,
+            |bytes| match &memory_map {
+                MemoryMap::Empty | MemoryMap::Simple(_) => {
+                    Err(MirEvalError::InvalidVTableId(from_bytes!(usize, bytes)))
+                }
+                MemoryMap::Complex(cm) => cm.vtable.ty_of_bytes(bytes),
+            },
+            addr,
+            ty,
+            locals,
+        )?;
         Ok(Interval::new(addr, size))
     }
 
@@ -1768,6 +1791,13 @@ impl Evaluator<'_> {
         Ok(())
     }
 
+    fn copy_from_interval_or_owned(&mut self, addr: Address, r: IntervalOrOwned) -> Result<()> {
+        match r {
+            IntervalOrOwned::Borrowed(r) => self.copy_from_interval(addr, r),
+            IntervalOrOwned::Owned(r) => self.write_memory(addr, &r),
+        }
+    }
+
     fn copy_from_interval(&mut self, addr: Address, r: Interval) -> Result<()> {
         if r.size == 0 {
             return Ok(());
@@ -1888,13 +1918,18 @@ impl Evaluator<'_> {
         }
     }
 
-    fn create_memory_map(&self, bytes: &[u8], ty: &Ty, locals: &Locals) -> Result<MemoryMap> {
+    fn create_memory_map(
+        &self,
+        bytes: &[u8],
+        ty: &Ty,
+        locals: &Locals,
+    ) -> Result<ComplexMemoryMap> {
         fn rec(
             this: &Evaluator<'_>,
             bytes: &[u8],
             ty: &Ty,
             locals: &Locals,
-            mm: &mut MemoryMap,
+            mm: &mut ComplexMemoryMap,
         ) -> Result<()> {
             match ty.kind(Interner) {
                 TyKind::Ref(_, _, t) => {
@@ -1904,7 +1939,7 @@ impl Evaluator<'_> {
                             let addr_usize = from_bytes!(usize, bytes);
                             mm.insert(
                                 addr_usize,
-                                this.read_memory(Address::from_usize(addr_usize), size)?.to_vec(),
+                                this.read_memory(Address::from_usize(addr_usize), size)?.into(),
                             )
                         }
                         None => {
@@ -1930,7 +1965,7 @@ impl Evaluator<'_> {
                             let size = element_size * count;
                             let addr = Address::from_bytes(addr)?;
                             let b = this.read_memory(addr, size)?;
-                            mm.insert(addr.to_usize(), b.to_vec());
+                            mm.insert(addr.to_usize(), b.into());
                             if let Some(ty) = check_inner {
                                 for i in 0..count {
                                     let offset = element_size * i;
@@ -2003,15 +2038,15 @@ impl Evaluator<'_> {
             }
             Ok(())
         }
-        let mut mm = MemoryMap::default();
-        rec(self, bytes, ty, locals, &mut mm)?;
+        let mut mm = ComplexMemoryMap::default();
+        rec(&self, bytes, ty, locals, &mut mm)?;
         Ok(mm)
     }
 
-    fn patch_addresses(
+    fn patch_addresses<'vtable>(
         &mut self,
-        patch_map: &HashMap<usize, usize>,
-        old_vtable: &VTableMap,
+        patch_map: &FxHashMap<usize, usize>,
+        ty_of_bytes: impl Fn(&[u8]) -> Result<&'vtable Ty> + Copy,
         addr: Address,
         ty: &Ty,
         locals: &Locals,
@@ -2038,7 +2073,7 @@ impl Evaluator<'_> {
                 }
             }
             TyKind::Function(_) => {
-                let ty = old_vtable.ty_of_bytes(self.read_memory(addr, my_size)?)?.clone();
+                let ty = ty_of_bytes(self.read_memory(addr, my_size)?)?.clone();
                 let new_id = self.vtable_map.id(ty);
                 self.write_memory(addr, &new_id.to_le_bytes())?;
             }
@@ -2049,7 +2084,7 @@ impl Evaluator<'_> {
                         let ty = ty.clone().substitute(Interner, subst);
                         self.patch_addresses(
                             patch_map,
-                            old_vtable,
+                            ty_of_bytes,
                             addr.offset(offset),
                             &ty,
                             locals,
@@ -2071,7 +2106,7 @@ impl Evaluator<'_> {
                             let ty = ty.clone().substitute(Interner, subst);
                             self.patch_addresses(
                                 patch_map,
-                                old_vtable,
+                                ty_of_bytes,
                                 addr.offset(offset),
                                 &ty,
                                 locals,
@@ -2084,7 +2119,7 @@ impl Evaluator<'_> {
                 for (id, ty) in subst.iter(Interner).enumerate() {
                     let ty = ty.assert_ty_ref(Interner); // Tuple only has type argument
                     let offset = layout.fields.offset(id).bytes_usize();
-                    self.patch_addresses(patch_map, old_vtable, addr.offset(offset), ty, locals)?;
+                    self.patch_addresses(patch_map, ty_of_bytes, addr.offset(offset), ty, locals)?;
                 }
             }
             TyKind::Array(inner, len) => {
@@ -2096,7 +2131,7 @@ impl Evaluator<'_> {
                 for i in 0..len {
                     self.patch_addresses(
                         patch_map,
-                        old_vtable,
+                        ty_of_bytes,
                         addr.offset(i * size),
                         inner,
                         locals,
@@ -2167,7 +2202,7 @@ impl Evaluator<'_> {
             .map_err(|it| MirEvalError::MirLowerErrorForClosure(closure, it))?;
         let closure_data = if mir_body.locals[mir_body.param_locals[0]].ty.as_reference().is_some()
         {
-            closure_data.addr.to_bytes()
+            closure_data.addr.to_bytes().to_vec()
         } else {
             closure_data.get(self)?.to_owned()
         };
@@ -2553,7 +2588,7 @@ impl Evaluator<'_> {
                 body,
                 locals,
                 drop_fn,
-                [IntervalOrOwned::Owned(addr.to_bytes())].into_iter(),
+                iter::once(IntervalOrOwned::Owned(addr.to_bytes().to_vec())),
                 span,
                 Interval { addr: Address::Invalid(0), size: 0 },
                 None,
diff --git a/crates/hir-ty/src/mir/eval/tests.rs b/crates/hir-ty/src/mir/eval/tests.rs
index b0f929279a5c..6552bf493377 100644
--- a/crates/hir-ty/src/mir/eval/tests.rs
+++ b/crates/hir-ty/src/mir/eval/tests.rs
@@ -31,9 +31,9 @@ fn eval_main(db: &TestDB, file_id: FileId) -> Result<(String, String), MirEvalEr
             db.trait_environment(func_id.into()),
         )
         .map_err(|e| MirEvalError::MirLowerError(func_id.into(), e))?;
-    let (result, stdout, stderr) = interpret_mir(db, body, false, None);
+    let (result, output) = interpret_mir(db, body, false, None);
     result?;
-    Ok((stdout, stderr))
+    Ok((output.stdout().into_owned(), output.stderr().into_owned()))
 }
 
 fn check_pass(ra_fixture: &str) {
diff --git a/crates/hir-ty/src/mir/lower.rs b/crates/hir-ty/src/mir/lower.rs
index a94da818b622..947fa3c21d6b 100644
--- a/crates/hir-ty/src/mir/lower.rs
+++ b/crates/hir-ty/src/mir/lower.rs
@@ -1403,31 +1403,27 @@ impl<'ctx> MirLowerCtx<'ctx> {
         const USIZE_SIZE: usize = mem::size_of::<usize>();
         let bytes: Box<[_]> = match l {
             hir_def::hir::Literal::String(b) => {
-                let b = b.as_bytes();
-                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                let mut data = [0; { 2 * USIZE_SIZE }];
                 data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
                 data[USIZE_SIZE..].copy_from_slice(&b.len().to_le_bytes());
-                let mut mm = MemoryMap::default();
-                mm.insert(0, b.to_vec());
-                return Ok(Operand::from_concrete_const(data, mm, ty));
+                let mm = MemoryMap::simple(b.as_bytes().into());
+                return Ok(Operand::from_concrete_const(Box::new(data), mm, ty));
             }
             hir_def::hir::Literal::CString(b) => {
-                let bytes = b.iter().copied().chain(iter::once(0)).collect::<Vec<_>>();
+                let bytes = b.iter().copied().chain(iter::once(0)).collect::<Box<_>>();
 
-                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                let mut data = [0; { 2 * USIZE_SIZE }];
                 data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
                 data[USIZE_SIZE..].copy_from_slice(&bytes.len().to_le_bytes());
-                let mut mm = MemoryMap::default();
-                mm.insert(0, bytes);
-                return Ok(Operand::from_concrete_const(data, mm, ty));
+                let mm = MemoryMap::simple(bytes);
+                return Ok(Operand::from_concrete_const(Box::new(data), mm, ty));
             }
             hir_def::hir::Literal::ByteString(b) => {
-                let mut data = Box::new([0; { 2 * USIZE_SIZE }]);
+                let mut data = [0; { 2 * USIZE_SIZE }];
                 data[..USIZE_SIZE].copy_from_slice(&0usize.to_le_bytes());
                 data[USIZE_SIZE..].copy_from_slice(&b.len().to_le_bytes());
-                let mut mm = MemoryMap::default();
-                mm.insert(0, b.to_vec());
-                return Ok(Operand::from_concrete_const(data, mm, ty));
+                let mm = MemoryMap::simple(b.clone());
+                return Ok(Operand::from_concrete_const(Box::new(data), mm, ty));
             }
             hir_def::hir::Literal::Char(c) => Box::new(u32::from(*c).to_le_bytes()),
             hir_def::hir::Literal::Bool(b) => Box::new([*b as u8]),
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index 4e4b758264f4..49f599a67a1a 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -2183,7 +2183,7 @@ impl Function {
                 return r;
             }
         };
-        let (result, stdout, stderr) = interpret_mir(db, body, false, None);
+        let (result, output) = interpret_mir(db, body, false, None);
         let mut text = match result {
             Ok(_) => "pass".to_string(),
             Err(e) => {
@@ -2192,10 +2192,12 @@ impl Function {
                 r
             }
         };
+        let stdout = output.stdout().into_owned();
         if !stdout.is_empty() {
             text += "\n--------- stdout ---------\n";
             text += &stdout;
         }
+        let stderr = output.stdout().into_owned();
         if !stderr.is_empty() {
             text += "\n--------- stderr ---------\n";
             text += &stderr;