Split SolverDelegate back out from InferCtxtLike

13 files changed, 286 insertions, 262 deletions

diff --git a/Cargo.lock b/Cargo.lock
index fbe1abf2a33..d1889fb6861 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4170,6 +4170,7 @@ dependencies = [
  "rustc_middle",
  "rustc_span",
  "rustc_target",
+ "rustc_type_ir",
  "smallvec",
  "tracing",
 ]
diff --git a/compiler/rustc_infer/Cargo.toml b/compiler/rustc_infer/Cargo.toml
index c1565a7d40f..5136ab79a0f 100644
--- a/compiler/rustc_infer/Cargo.toml
+++ b/compiler/rustc_infer/Cargo.toml
@@ -18,6 +18,7 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
+rustc_type_ir = { path = "../rustc_type_ir" }
 smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 # tidy-alphabetical-end
diff --git a/compiler/rustc_infer/src/infer/context.rs b/compiler/rustc_infer/src/infer/context.rs
new file mode 100644
index 00000000000..209996b12e2
--- /dev/null
+++ b/compiler/rustc_infer/src/infer/context.rs
@@ -0,0 +1,172 @@
+///! Definition of `InferCtxtLike` from the librarified type layer.
+use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_middle::traits::solve::{Goal, NoSolution, SolverMode};
+use rustc_middle::traits::ObligationCause;
+use rustc_middle::ty::fold::TypeFoldable;
+use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_span::DUMMY_SP;
+use rustc_type_ir::relate::Relate;
+use rustc_type_ir::InferCtxtLike;
+
+use super::{BoundRegionConversionTime, InferCtxt, SubregionOrigin};
+
+impl<'tcx> InferCtxtLike for InferCtxt<'tcx> {
+    type Interner = TyCtxt<'tcx>;
+
+    fn cx(&self) -> TyCtxt<'tcx> {
+        self.tcx
+    }
+
+    fn solver_mode(&self) -> ty::solve::SolverMode {
+        match self.intercrate {
+            true => SolverMode::Coherence,
+            false => SolverMode::Normal,
+        }
+    }
+
+    fn universe(&self) -> ty::UniverseIndex {
+        self.universe()
+    }
+
+    fn create_next_universe(&self) -> ty::UniverseIndex {
+        self.create_next_universe()
+    }
+
+    fn universe_of_ty(&self, vid: ty::TyVid) -> Option<ty::UniverseIndex> {
+        match self.probe_ty_var(vid) {
+            Err(universe) => Some(universe),
+            Ok(_) => None,
+        }
+    }
+
+    fn universe_of_lt(&self, lt: ty::RegionVid) -> Option<ty::UniverseIndex> {
+        match self.inner.borrow_mut().unwrap_region_constraints().probe_value(lt) {
+            Err(universe) => Some(universe),
+            Ok(_) => None,
+        }
+    }
+
+    fn universe_of_ct(&self, ct: ty::ConstVid) -> Option<ty::UniverseIndex> {
+        match self.probe_const_var(ct) {
+            Err(universe) => Some(universe),
+            Ok(_) => None,
+        }
+    }
+
+    fn root_ty_var(&self, var: ty::TyVid) -> ty::TyVid {
+        self.root_var(var)
+    }
+
+    fn root_const_var(&self, var: ty::ConstVid) -> ty::ConstVid {
+        self.root_const_var(var)
+    }
+
+    fn opportunistic_resolve_ty_var(&self, vid: ty::TyVid) -> Ty<'tcx> {
+        match self.probe_ty_var(vid) {
+            Ok(ty) => ty,
+            Err(_) => Ty::new_var(self.tcx, self.root_var(vid)),
+        }
+    }
+
+    fn opportunistic_resolve_int_var(&self, vid: ty::IntVid) -> Ty<'tcx> {
+        self.opportunistic_resolve_int_var(vid)
+    }
+
+    fn opportunistic_resolve_float_var(&self, vid: ty::FloatVid) -> Ty<'tcx> {
+        self.opportunistic_resolve_float_var(vid)
+    }
+
+    fn opportunistic_resolve_ct_var(&self, vid: ty::ConstVid) -> ty::Const<'tcx> {
+        match self.probe_const_var(vid) {
+            Ok(ct) => ct,
+            Err(_) => ty::Const::new_var(self.tcx, self.root_const_var(vid)),
+        }
+    }
+
+    fn opportunistic_resolve_effect_var(&self, vid: ty::EffectVid) -> ty::Const<'tcx> {
+        match self.probe_effect_var(vid) {
+            Some(ct) => ct,
+            None => {
+                ty::Const::new_infer(self.tcx, ty::InferConst::EffectVar(self.root_effect_var(vid)))
+            }
+        }
+    }
+
+    fn opportunistic_resolve_lt_var(&self, vid: ty::RegionVid) -> ty::Region<'tcx> {
+        self.inner.borrow_mut().unwrap_region_constraints().opportunistic_resolve_var(self.tcx, vid)
+    }
+
+    fn defining_opaque_types(&self) -> &'tcx ty::List<LocalDefId> {
+        self.defining_opaque_types()
+    }
+
+    fn next_ty_infer(&self) -> Ty<'tcx> {
+        self.next_ty_var(DUMMY_SP)
+    }
+
+    fn next_const_infer(&self) -> ty::Const<'tcx> {
+        self.next_const_var(DUMMY_SP)
+    }
+
+    fn fresh_args_for_item(&self, def_id: DefId) -> ty::GenericArgsRef<'tcx> {
+        self.fresh_args_for_item(DUMMY_SP, def_id)
+    }
+
+    fn instantiate_binder_with_infer<T: TypeFoldable<TyCtxt<'tcx>> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T {
+        self.instantiate_binder_with_fresh_vars(
+            DUMMY_SP,
+            BoundRegionConversionTime::HigherRankedType,
+            value,
+        )
+    }
+
+    fn enter_forall<T: TypeFoldable<TyCtxt<'tcx>> + Copy, U>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+        f: impl FnOnce(T) -> U,
+    ) -> U {
+        self.enter_forall(value, f)
+    }
+
+    fn relate<T: Relate<TyCtxt<'tcx>>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        variance: ty::Variance,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
+        self.at(&ObligationCause::dummy(), param_env).relate_no_trace(lhs, variance, rhs)
+    }
+
+    fn eq_structurally_relating_aliases<T: Relate<TyCtxt<'tcx>>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
+        self.at(&ObligationCause::dummy(), param_env)
+            .eq_structurally_relating_aliases_no_trace(lhs, rhs)
+    }
+
+    fn resolve_vars_if_possible<T>(&self, value: T) -> T
+    where
+        T: TypeFoldable<TyCtxt<'tcx>>,
+    {
+        self.resolve_vars_if_possible(value)
+    }
+
+    fn probe<T>(&self, probe: impl FnOnce() -> T) -> T {
+        self.probe(|_| probe())
+    }
+
+    fn sub_regions(&self, sub: ty::Region<'tcx>, sup: ty::Region<'tcx>) {
+        self.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), sub, sup)
+    }
+
+    fn register_ty_outlives(&self, ty: Ty<'tcx>, r: ty::Region<'tcx>) {
+        self.register_region_obligation_with_cause(ty, r, &ObligationCause::dummy());
+    }
+}
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index ff593d7ffb7..edbb741036f 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -53,6 +53,7 @@ use type_variable::TypeVariableOrigin;
 
 pub mod at;
 pub mod canonical;
+mod context;
 pub mod error_reporting;
 pub mod free_regions;
 mod freshen;
diff --git a/compiler/rustc_next_trait_solver/src/canonicalizer.rs b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
index 695d02705ab..82488088e30 100644
--- a/compiler/rustc_next_trait_solver/src/canonicalizer.rs
+++ b/compiler/rustc_next_trait_solver/src/canonicalizer.rs
@@ -4,7 +4,8 @@ use rustc_type_ir::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::visit::TypeVisitableExt;
 use rustc_type_ir::{
-    self as ty, Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, Interner,
+    self as ty, Canonical, CanonicalTyVarKind, CanonicalVarInfo, CanonicalVarKind, InferCtxtLike,
+    Interner,
 };
 
 use crate::delegate::SolverDelegate;
diff --git a/compiler/rustc_next_trait_solver/src/delegate.rs b/compiler/rustc_next_trait_solver/src/delegate.rs
index 6626acfe963..31032dc679a 100644
--- a/compiler/rustc_next_trait_solver/src/delegate.rs
+++ b/compiler/rustc_next_trait_solver/src/delegate.rs
@@ -1,18 +1,20 @@
 use std::fmt::Debug;
+use std::ops::Deref;
 
 use rustc_type_ir::fold::TypeFoldable;
-use rustc_type_ir::relate::Relate;
 use rustc_type_ir::solve::{Certainty, Goal, NoSolution, SolverMode};
-use rustc_type_ir::{self as ty, Interner};
+use rustc_type_ir::{self as ty, InferCtxtLike, Interner};
 
-pub trait SolverDelegate: Sized {
+pub trait SolverDelegate:
+    Deref<Target: InferCtxtLike<Interner = <Self as SolverDelegate>::Interner>> + Sized
+{
     type Interner: Interner;
-    fn cx(&self) -> Self::Interner;
+    fn cx(&self) -> Self::Interner {
+        (**self).cx()
+    }
 
     type Span: Copy;
 
-    fn solver_mode(&self) -> SolverMode;
-
     fn build_with_canonical<V>(
         cx: Self::Interner,
         solver_mode: SolverMode,
@@ -21,82 +23,12 @@ pub trait SolverDelegate: Sized {
     where
         V: TypeFoldable<Self::Interner>;
 
-    fn universe(&self) -> ty::UniverseIndex;
-    fn create_next_universe(&self) -> ty::UniverseIndex;
-
-    fn universe_of_ty(&self, ty: ty::TyVid) -> Option<ty::UniverseIndex>;
-    fn universe_of_lt(&self, lt: ty::RegionVid) -> Option<ty::UniverseIndex>;
-    fn universe_of_ct(&self, ct: ty::ConstVid) -> Option<ty::UniverseIndex>;
-
-    fn root_ty_var(&self, var: ty::TyVid) -> ty::TyVid;
-    fn root_const_var(&self, var: ty::ConstVid) -> ty::ConstVid;
-
-    fn opportunistic_resolve_ty_var(&self, vid: ty::TyVid) -> <Self::Interner as Interner>::Ty;
-    fn opportunistic_resolve_int_var(&self, vid: ty::IntVid) -> <Self::Interner as Interner>::Ty;
-    fn opportunistic_resolve_float_var(
-        &self,
-        vid: ty::FloatVid,
-    ) -> <Self::Interner as Interner>::Ty;
-    fn opportunistic_resolve_ct_var(
-        &self,
-        vid: ty::ConstVid,
-    ) -> <Self::Interner as Interner>::Const;
-    fn opportunistic_resolve_effect_var(
-        &self,
-        vid: ty::EffectVid,
-    ) -> <Self::Interner as Interner>::Const;
-    fn opportunistic_resolve_lt_var(
-        &self,
-        vid: ty::RegionVid,
-    ) -> <Self::Interner as Interner>::Region;
-
-    fn defining_opaque_types(&self) -> <Self::Interner as Interner>::DefiningOpaqueTypes;
-
-    fn next_ty_infer(&self) -> <Self::Interner as Interner>::Ty;
-    fn next_const_infer(&self) -> <Self::Interner as Interner>::Const;
-    fn fresh_args_for_item(
-        &self,
-        def_id: <Self::Interner as Interner>::DefId,
-    ) -> <Self::Interner as Interner>::GenericArgs;
-
     fn fresh_var_for_kind_with_span(
         &self,
         arg: <Self::Interner as Interner>::GenericArg,
         span: Self::Span,
     ) -> <Self::Interner as Interner>::GenericArg;
 
-    fn instantiate_binder_with_infer<T: TypeFoldable<Self::Interner> + Copy>(
-        &self,
-        value: ty::Binder<Self::Interner, T>,
-    ) -> T;
-
-    fn enter_forall<T: TypeFoldable<Self::Interner> + Copy, U>(
-        &self,
-        value: ty::Binder<Self::Interner, T>,
-        f: impl FnOnce(T) -> U,
-    ) -> U;
-
-    fn relate<T: Relate<Self::Interner>>(
-        &self,
-        param_env: <Self::Interner as Interner>::ParamEnv,
-        lhs: T,
-        variance: ty::Variance,
-        rhs: T,
-    ) -> Result<Vec<Goal<Self::Interner, <Self::Interner as Interner>::Predicate>>, NoSolution>;
-
-    fn eq_structurally_relating_aliases<T: Relate<Self::Interner>>(
-        &self,
-        param_env: <Self::Interner as Interner>::ParamEnv,
-        lhs: T,
-        rhs: T,
-    ) -> Result<Vec<Goal<Self::Interner, <Self::Interner as Interner>::Predicate>>, NoSolution>;
-
-    fn resolve_vars_if_possible<T>(&self, value: T) -> T
-    where
-        T: TypeFoldable<Self::Interner>;
-
-    fn probe<T>(&self, probe: impl FnOnce() -> T) -> T;
-
     // FIXME: Uplift the leak check into this crate.
     fn leak_check(&self, max_input_universe: ty::UniverseIndex) -> Result<(), NoSolution>;
 
@@ -112,18 +44,6 @@ pub trait SolverDelegate: Sized {
         unevaluated: ty::UnevaluatedConst<Self::Interner>,
     ) -> Option<<Self::Interner as Interner>::Const>;
 
-    fn sub_regions(
-        &self,
-        sub: <Self::Interner as Interner>::Region,
-        sup: <Self::Interner as Interner>::Region,
-    );
-
-    fn register_ty_outlives(
-        &self,
-        ty: <Self::Interner as Interner>::Ty,
-        r: <Self::Interner as Interner>::Region,
-    );
-
     // FIXME: This only is here because `wf::obligations` is in `rustc_trait_selection`!
     fn well_formed_goals(
         &self,
diff --git a/compiler/rustc_next_trait_solver/src/resolve.rs b/compiler/rustc_next_trait_solver/src/resolve.rs
index 6ed58d0e4fb..254ee514f8b 100644
--- a/compiler/rustc_next_trait_solver/src/resolve.rs
+++ b/compiler/rustc_next_trait_solver/src/resolve.rs
@@ -2,7 +2,7 @@ use crate::delegate::SolverDelegate;
 use rustc_type_ir::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::visit::TypeVisitableExt;
-use rustc_type_ir::{self as ty, Interner};
+use rustc_type_ir::{self as ty, InferCtxtLike, Interner};
 
 ///////////////////////////////////////////////////////////////////////////
 // EAGER RESOLUTION
diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
index 0a313c6a951..9474d501d6f 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/canonical.rs
@@ -14,7 +14,7 @@ use std::iter;
 use rustc_index::IndexVec;
 use rustc_type_ir::fold::TypeFoldable;
 use rustc_type_ir::inherent::*;
-use rustc_type_ir::{self as ty, Canonical, CanonicalVarValues, Interner};
+use rustc_type_ir::{self as ty, Canonical, CanonicalVarValues, InferCtxtLike, Interner};
 use tracing::{instrument, trace};
 
 use crate::canonicalizer::{CanonicalizeMode, Canonicalizer};
diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
index 87342eefb33..d8a3acc655a 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs
@@ -7,7 +7,7 @@ use rustc_type_ir::fold::{TypeFoldable, TypeFolder, TypeSuperFoldable};
 use rustc_type_ir::inherent::*;
 use rustc_type_ir::relate::Relate;
 use rustc_type_ir::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor};
-use rustc_type_ir::{self as ty, CanonicalVarValues, Interner};
+use rustc_type_ir::{self as ty, CanonicalVarValues, InferCtxtLike, Interner};
 use rustc_type_ir_macros::{Lift_Generic, TypeFoldable_Generic, TypeVisitable_Generic};
 use tracing::{instrument, trace};
 
diff --git a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/probe.rs b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/probe.rs
index e9516c60c70..4258dd9263a 100644
--- a/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/probe.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/eval_ctxt/probe.rs
@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use rustc_type_ir::Interner;
+use rustc_type_ir::{InferCtxtLike, Interner};
 use tracing::instrument;
 
 use crate::delegate::SolverDelegate;
diff --git a/compiler/rustc_trait_selection/src/solve/delegate.rs b/compiler/rustc_trait_selection/src/solve/delegate.rs
index 643d5f80480..f98744e906f 100644
--- a/compiler/rustc_trait_selection/src/solve/delegate.rs
+++ b/compiler/rustc_trait_selection/src/solve/delegate.rs
@@ -1,21 +1,18 @@
 use std::ops::Deref;
 
 use rustc_data_structures::fx::FxHashSet;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::DefId;
 use rustc_infer::infer::canonical::query_response::make_query_region_constraints;
 use rustc_infer::infer::canonical::{
     Canonical, CanonicalExt as _, CanonicalVarInfo, CanonicalVarValues,
 };
-use rustc_infer::infer::{
-    BoundRegionConversionTime, InferCtxt, RegionVariableOrigin, SubregionOrigin, TyCtxtInferExt,
-};
+use rustc_infer::infer::{InferCtxt, RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::solve::Goal;
 use rustc_infer::traits::util::supertraits;
 use rustc_infer::traits::{ObligationCause, Reveal};
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitableExt as _};
 use rustc_span::{ErrorGuaranteed, Span, DUMMY_SP};
-use rustc_type_ir::relate::Relate;
 use rustc_type_ir::solve::{Certainty, NoSolution, SolverMode};
 
 use crate::traits::coherence::trait_ref_is_knowable;
@@ -48,13 +45,6 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
 
     type Span = Span;
 
-    fn solver_mode(&self) -> ty::solve::SolverMode {
-        match self.intercrate {
-            true => SolverMode::Coherence,
-            false => SolverMode::Normal,
-        }
-    }
-
     fn build_with_canonical<V>(
         interner: TyCtxt<'tcx>,
         solver_mode: SolverMode,
@@ -74,104 +64,6 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
         (SolverDelegate(infcx), value, vars)
     }
 
-    fn universe(&self) -> ty::UniverseIndex {
-        self.0.universe()
-    }
-
-    fn create_next_universe(&self) -> ty::UniverseIndex {
-        self.0.create_next_universe()
-    }
-
-    fn universe_of_ty(&self, vid: ty::TyVid) -> Option<ty::UniverseIndex> {
-        // FIXME(BoxyUwU): this is kind of jank and means that printing unresolved
-        // ty infers will give you the universe of the var it resolved to not the universe
-        // it actually had. It also means that if you have a `?0.1` and infer it to `u8` then
-        // try to print out `?0.1` it will just print `?0`.
-        match self.0.probe_ty_var(vid) {
-            Err(universe) => Some(universe),
-            Ok(_) => None,
-        }
-    }
-
-    fn universe_of_lt(&self, lt: ty::RegionVid) -> Option<ty::UniverseIndex> {
-        match self.0.inner.borrow_mut().unwrap_region_constraints().probe_value(lt) {
-            Err(universe) => Some(universe),
-            Ok(_) => None,
-        }
-    }
-
-    fn universe_of_ct(&self, ct: ty::ConstVid) -> Option<ty::UniverseIndex> {
-        // Same issue as with `universe_of_ty`
-        match self.0.probe_const_var(ct) {
-            Err(universe) => Some(universe),
-            Ok(_) => None,
-        }
-    }
-
-    fn root_ty_var(&self, var: ty::TyVid) -> ty::TyVid {
-        self.0.root_var(var)
-    }
-
-    fn root_const_var(&self, var: ty::ConstVid) -> ty::ConstVid {
-        self.0.root_const_var(var)
-    }
-
-    fn opportunistic_resolve_ty_var(&self, vid: ty::TyVid) -> Ty<'tcx> {
-        match self.0.probe_ty_var(vid) {
-            Ok(ty) => ty,
-            Err(_) => Ty::new_var(self.0.tcx, self.0.root_var(vid)),
-        }
-    }
-
-    fn opportunistic_resolve_int_var(&self, vid: ty::IntVid) -> Ty<'tcx> {
-        self.0.opportunistic_resolve_int_var(vid)
-    }
-
-    fn opportunistic_resolve_float_var(&self, vid: ty::FloatVid) -> Ty<'tcx> {
-        self.0.opportunistic_resolve_float_var(vid)
-    }
-
-    fn opportunistic_resolve_ct_var(&self, vid: ty::ConstVid) -> ty::Const<'tcx> {
-        match self.0.probe_const_var(vid) {
-            Ok(ct) => ct,
-            Err(_) => ty::Const::new_var(self.0.tcx, self.0.root_const_var(vid)),
-        }
-    }
-
-    fn opportunistic_resolve_effect_var(&self, vid: ty::EffectVid) -> ty::Const<'tcx> {
-        match self.0.probe_effect_var(vid) {
-            Some(ct) => ct,
-            None => ty::Const::new_infer(
-                self.0.tcx,
-                ty::InferConst::EffectVar(self.0.root_effect_var(vid)),
-            ),
-        }
-    }
-
-    fn opportunistic_resolve_lt_var(&self, vid: ty::RegionVid) -> ty::Region<'tcx> {
-        self.0
-            .inner
-            .borrow_mut()
-            .unwrap_region_constraints()
-            .opportunistic_resolve_var(self.0.tcx, vid)
-    }
-
-    fn defining_opaque_types(&self) -> &'tcx ty::List<LocalDefId> {
-        self.0.defining_opaque_types()
-    }
-
-    fn next_ty_infer(&self) -> Ty<'tcx> {
-        self.0.next_ty_var(DUMMY_SP)
-    }
-
-    fn next_const_infer(&self) -> ty::Const<'tcx> {
-        self.0.next_const_var(DUMMY_SP)
-    }
-
-    fn fresh_args_for_item(&self, def_id: DefId) -> ty::GenericArgsRef<'tcx> {
-        self.0.fresh_args_for_item(DUMMY_SP, def_id)
-    }
-
     fn fresh_var_for_kind_with_span(
         &self,
         arg: ty::GenericArg<'tcx>,
@@ -186,57 +78,6 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
         }
     }
 
-    fn instantiate_binder_with_infer<T: TypeFoldable<TyCtxt<'tcx>> + Copy>(
-        &self,
-        value: ty::Binder<'tcx, T>,
-    ) -> T {
-        self.0.instantiate_binder_with_fresh_vars(
-            DUMMY_SP,
-            BoundRegionConversionTime::HigherRankedType,
-            value,
-        )
-    }
-
-    fn enter_forall<T: TypeFoldable<TyCtxt<'tcx>> + Copy, U>(
-        &self,
-        value: ty::Binder<'tcx, T>,
-        f: impl FnOnce(T) -> U,
-    ) -> U {
-        self.0.enter_forall(value, f)
-    }
-
-    fn relate<T: Relate<TyCtxt<'tcx>>>(
-        &self,
-        param_env: ty::ParamEnv<'tcx>,
-        lhs: T,
-        variance: ty::Variance,
-        rhs: T,
-    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
-        self.0.at(&ObligationCause::dummy(), param_env).relate_no_trace(lhs, variance, rhs)
-    }
-
-    fn eq_structurally_relating_aliases<T: Relate<TyCtxt<'tcx>>>(
-        &self,
-        param_env: ty::ParamEnv<'tcx>,
-        lhs: T,
-        rhs: T,
-    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
-        self.0
-            .at(&ObligationCause::dummy(), param_env)
-            .eq_structurally_relating_aliases_no_trace(lhs, rhs)
-    }
-
-    fn resolve_vars_if_possible<T>(&self, value: T) -> T
-    where
-        T: TypeFoldable<TyCtxt<'tcx>>,
-    {
-        self.0.resolve_vars_if_possible(value)
-    }
-
-    fn probe<T>(&self, probe: impl FnOnce() -> T) -> T {
-        self.0.probe(|_| probe())
-    }
-
     fn leak_check(&self, max_input_universe: ty::UniverseIndex) -> Result<(), NoSolution> {
         self.0.leak_check(max_input_universe, None).map_err(|_| NoSolution)
     }
@@ -265,14 +106,6 @@ impl<'tcx> rustc_next_trait_solver::delegate::SolverDelegate for SolverDelegate<
         }
     }
 
-    fn sub_regions(&self, sub: ty::Region<'tcx>, sup: ty::Region<'tcx>) {
-        self.0.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), sub, sup)
-    }
-
-    fn register_ty_outlives(&self, ty: Ty<'tcx>, r: ty::Region<'tcx>) {
-        self.0.register_region_obligation_with_cause(ty, r, &ObligationCause::dummy());
-    }
-
     fn well_formed_goals(
         &self,
         param_env: ty::ParamEnv<'tcx>,
diff --git a/compiler/rustc_type_ir/src/infer_ctxt.rs b/compiler/rustc_type_ir/src/infer_ctxt.rs
new file mode 100644
index 00000000000..2c80ee0a73d
--- /dev/null
+++ b/compiler/rustc_type_ir/src/infer_ctxt.rs
@@ -0,0 +1,93 @@
+use crate::fold::TypeFoldable;
+use crate::relate::Relate;
+use crate::solve::{Goal, NoSolution, SolverMode};
+use crate::{self as ty, Interner};
+
+pub trait InferCtxtLike {
+    type Interner: Interner;
+    fn cx(&self) -> Self::Interner;
+
+    fn solver_mode(&self) -> SolverMode;
+
+    fn universe(&self) -> ty::UniverseIndex;
+    fn create_next_universe(&self) -> ty::UniverseIndex;
+
+    fn universe_of_ty(&self, ty: ty::TyVid) -> Option<ty::UniverseIndex>;
+    fn universe_of_lt(&self, lt: ty::RegionVid) -> Option<ty::UniverseIndex>;
+    fn universe_of_ct(&self, ct: ty::ConstVid) -> Option<ty::UniverseIndex>;
+
+    fn root_ty_var(&self, var: ty::TyVid) -> ty::TyVid;
+    fn root_const_var(&self, var: ty::ConstVid) -> ty::ConstVid;
+
+    fn opportunistic_resolve_ty_var(&self, vid: ty::TyVid) -> <Self::Interner as Interner>::Ty;
+    fn opportunistic_resolve_int_var(&self, vid: ty::IntVid) -> <Self::Interner as Interner>::Ty;
+    fn opportunistic_resolve_float_var(
+        &self,
+        vid: ty::FloatVid,
+    ) -> <Self::Interner as Interner>::Ty;
+    fn opportunistic_resolve_ct_var(
+        &self,
+        vid: ty::ConstVid,
+    ) -> <Self::Interner as Interner>::Const;
+    fn opportunistic_resolve_effect_var(
+        &self,
+        vid: ty::EffectVid,
+    ) -> <Self::Interner as Interner>::Const;
+    fn opportunistic_resolve_lt_var(
+        &self,
+        vid: ty::RegionVid,
+    ) -> <Self::Interner as Interner>::Region;
+
+    fn defining_opaque_types(&self) -> <Self::Interner as Interner>::DefiningOpaqueTypes;
+
+    fn next_ty_infer(&self) -> <Self::Interner as Interner>::Ty;
+    fn next_const_infer(&self) -> <Self::Interner as Interner>::Const;
+    fn fresh_args_for_item(
+        &self,
+        def_id: <Self::Interner as Interner>::DefId,
+    ) -> <Self::Interner as Interner>::GenericArgs;
+
+    fn instantiate_binder_with_infer<T: TypeFoldable<Self::Interner> + Copy>(
+        &self,
+        value: ty::Binder<Self::Interner, T>,
+    ) -> T;
+
+    fn enter_forall<T: TypeFoldable<Self::Interner> + Copy, U>(
+        &self,
+        value: ty::Binder<Self::Interner, T>,
+        f: impl FnOnce(T) -> U,
+    ) -> U;
+
+    fn relate<T: Relate<Self::Interner>>(
+        &self,
+        param_env: <Self::Interner as Interner>::ParamEnv,
+        lhs: T,
+        variance: ty::Variance,
+        rhs: T,
+    ) -> Result<Vec<Goal<Self::Interner, <Self::Interner as Interner>::Predicate>>, NoSolution>;
+
+    fn eq_structurally_relating_aliases<T: Relate<Self::Interner>>(
+        &self,
+        param_env: <Self::Interner as Interner>::ParamEnv,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<Self::Interner, <Self::Interner as Interner>::Predicate>>, NoSolution>;
+
+    fn resolve_vars_if_possible<T>(&self, value: T) -> T
+    where
+        T: TypeFoldable<Self::Interner>;
+
+    fn probe<T>(&self, probe: impl FnOnce() -> T) -> T;
+
+    fn sub_regions(
+        &self,
+        sub: <Self::Interner as Interner>::Region,
+        sup: <Self::Interner as Interner>::Region,
+    );
+
+    fn register_ty_outlives(
+        &self,
+        ty: <Self::Interner as Interner>::Ty,
+        r: <Self::Interner as Interner>::Region,
+    );
+}
diff --git a/compiler/rustc_type_ir/src/lib.rs b/compiler/rustc_type_ir/src/lib.rs
index fedc8959cf7..c57ac74cdfd 100644
--- a/compiler/rustc_type_ir/src/lib.rs
+++ b/compiler/rustc_type_ir/src/lib.rs
@@ -39,6 +39,7 @@ mod const_kind;
 mod effects;
 mod flags;
 mod generic_arg;
+mod infer_ctxt;
 mod interner;
 mod opaque_ty;
 mod predicate;
@@ -56,6 +57,7 @@ pub use const_kind::*;
 pub use effects::*;
 pub use flags::*;
 pub use generic_arg::*;
+pub use infer_ctxt::*;
 pub use interner::*;
 pub use opaque_ty::*;
 pub use predicate::*;