2 files changed, 43 insertions, 30 deletions

diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/traits/chalk.rs
index 011bef6f6..541e6082f 100644
--- a/crates/hir_ty/src/traits/chalk.rs
+++ b/crates/hir_ty/src/traits/chalk.rs
@@ -3,7 +3,7 @@ use std::sync::Arc;
 
 use log::debug;
 
-use chalk_ir::{fold::shift::Shift, CanonicalVarKinds, GenericArg};
+use chalk_ir::{fold::shift::Shift, CanonicalVarKinds};
 use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
 
 use base_db::{salsa::InternKey, CrateId};
@@ -22,7 +22,7 @@ use crate::{
     to_assoc_type_id, to_chalk_trait_id,
     utils::generics,
     AliasEq, AliasTy, BoundVar, CallableDefId, DebruijnIndex, FnDefId, ProjectionTy, Substitution,
-    TraitRef, Ty, TyKind, WhereClause,
+    TraitRef, Ty, TyBuilder, TyKind, WhereClause,
 };
 use mapping::{
     convert_where_clauses, generic_predicate_to_inline_bound, make_binders, TypeAliasAsValue,
@@ -80,7 +80,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
     fn impls_for_trait(
         &self,
         trait_id: TraitId,
-        parameters: &[GenericArg<Interner>],
+        parameters: &[chalk_ir::GenericArg<Interner>],
         binders: &CanonicalVarKinds<Interner>,
     ) -> Vec<ImplId> {
         debug!("impls_for_trait {:?}", trait_id);
@@ -92,7 +92,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
             ty: &Ty,
             binders: &CanonicalVarKinds<Interner>,
         ) -> Option<chalk_ir::TyVariableKind> {
-            if let TyKind::BoundVar(bv) = ty.interned(&Interner) {
+            if let TyKind::BoundVar(bv) = ty.kind(&Interner) {
                 let binders = binders.as_slice(&Interner);
                 if bv.debruijn == DebruijnIndex::INNERMOST {
                     if let chalk_ir::VariableKind::Ty(tk) = binders[bv.index].kind {
@@ -300,7 +300,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         _closure_id: chalk_ir::ClosureId<Interner>,
         _substs: &chalk_ir::Substitution<Interner>,
     ) -> chalk_ir::Binders<chalk_ir::Ty<Interner>> {
-        let ty = Ty::unit().to_chalk(self.db);
+        let ty = TyBuilder::unit().to_chalk(self.db);
         make_binders(ty, 0)
     }
     fn closure_fn_substitution(
@@ -308,7 +308,7 @@ impl<'a> chalk_solve::RustIrDatabase<Interner> for ChalkContext<'a> {
         _closure_id: chalk_ir::ClosureId<Interner>,
         _substs: &chalk_ir::Substitution<Interner>,
     ) -> chalk_ir::Substitution<Interner> {
-        Substitution::empty().to_chalk(self.db)
+        Substitution::empty(&Interner).to_chalk(self.db)
     }
 
     fn trait_name(&self, trait_id: chalk_ir::TraitId<Interner>) -> String {
@@ -387,7 +387,7 @@ pub(crate) fn associated_ty_data_query(
     // Lower bounds -- we could/should maybe move this to a separate query in `lower`
     let type_alias_data = db.type_alias_data(type_alias);
     let generic_params = generics(db.upcast(), type_alias.into());
-    let bound_vars = Substitution::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
     let resolver = hir_def::resolver::HasResolver::resolver(type_alias, db.upcast());
     let ctx = crate::TyLoweringContext::new(db, &resolver)
         .with_type_param_mode(crate::lower::TypeParamLoweringMode::Variable);
@@ -421,7 +421,7 @@ pub(crate) fn trait_datum_query(
     let trait_data = db.trait_data(trait_);
     debug!("trait {:?} = {:?}", trait_id, trait_data.name);
     let generic_params = generics(db.upcast(), trait_.into());
-    let bound_vars = Substitution::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
     let flags = rust_ir::TraitFlags {
         auto: trait_data.is_auto,
         upstream: trait_.lookup(db.upcast()).container.krate() != krate,
@@ -439,7 +439,7 @@ pub(crate) fn trait_datum_query(
         lang_attr(db.upcast(), trait_).and_then(|name| well_known_trait_from_lang_attr(&name));
     let trait_datum = TraitDatum {
         id: trait_id,
-        binders: make_binders(trait_datum_bound, bound_vars.len()),
+        binders: make_binders(trait_datum_bound, bound_vars.len(&Interner)),
         flags,
         associated_ty_ids,
         well_known,
@@ -490,7 +490,7 @@ pub(crate) fn struct_datum_query(
     let upstream = adt_id.module(db.upcast()).krate() != krate;
     let where_clauses = {
         let generic_params = generics(db.upcast(), adt_id.into());
-        let bound_vars = Substitution::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+        let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
         convert_where_clauses(db, adt_id.into(), &bound_vars)
     };
     let flags = rust_ir::AdtFlags {
@@ -539,7 +539,7 @@ fn impl_def_datum(
     let impl_data = db.impl_data(impl_id);
 
     let generic_params = generics(db.upcast(), impl_id.into());
-    let bound_vars = Substitution::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
     let trait_ = trait_ref.hir_trait_id();
     let impl_type = if impl_id.lookup(db.upcast()).container.krate() == krate {
         rust_ir::ImplType::Local
@@ -577,7 +577,7 @@ fn impl_def_datum(
         .collect();
     debug!("impl_datum: {:?}", impl_datum_bound);
     let impl_datum = ImplDatum {
-        binders: make_binders(impl_datum_bound, bound_vars.len()),
+        binders: make_binders(impl_datum_bound, bound_vars.len(&Interner)),
         impl_type,
         polarity,
         associated_ty_value_ids,
@@ -629,7 +629,7 @@ pub(crate) fn fn_def_datum_query(
     let callable_def: CallableDefId = from_chalk(db, fn_def_id);
     let generic_params = generics(db.upcast(), callable_def.into());
     let sig = db.callable_item_signature(callable_def);
-    let bound_vars = Substitution::bound_vars(&generic_params, DebruijnIndex::INNERMOST);
+    let bound_vars = generic_params.bound_vars_subst(DebruijnIndex::INNERMOST);
     let where_clauses = convert_where_clauses(db, callable_def.into(), &bound_vars);
     let bound = rust_ir::FnDefDatumBound {
         // Note: Chalk doesn't actually use this information yet as far as I am aware, but we provide it anyway
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index aef6b8a15..5e4f97a46 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -10,11 +10,9 @@ use base_db::salsa::InternKey;
 use hir_def::{GenericDefId, TypeAliasId};
 
 use crate::{
-    db::HirDatabase,
-    primitive::UintTy,
-    traits::{Canonical, DomainGoal},
-    AliasTy, CallableDefId, FnPointer, InEnvironment, OpaqueTy, ProjectionTy,
-    QuantifiedWhereClause, Scalar, Substitution, TraitRef, Ty, TypeWalk, WhereClause,
+    db::HirDatabase, primitive::UintTy, AliasTy, CallableDefId, Canonical, DomainGoal, FnPointer,
+    GenericArg, InEnvironment, OpaqueTy, ProjectionTy, QuantifiedWhereClause, Scalar, Substitution,
+    TraitRef, Ty, TypeWalk, WhereClause,
 };
 
 use super::interner::*;
@@ -137,7 +135,7 @@ impl ToChalk for Ty {
                     db,
                     substitution.0.shifted_out(&Interner).expect("fn ptr should have no binders"),
                 );
-                TyKind::Function(FnPointer { num_args: (substs.len() - 1), sig, substs })
+                TyKind::Function(FnPointer { num_args: (substs.len(&Interner) - 1), sig, substs })
             }
             chalk_ir::TyKind::BoundVar(idx) => TyKind::BoundVar(idx),
             chalk_ir::TyKind::InferenceVar(_iv, _kind) => TyKind::Unknown,
@@ -216,25 +214,40 @@ fn array_to_chalk(db: &dyn HirDatabase, ty: Ty) -> chalk_ir::Ty<Interner> {
     chalk_ir::TyKind::Array(arg, const_).intern(&Interner)
 }
 
+impl ToChalk for GenericArg {
+    type Chalk = chalk_ir::GenericArg<Interner>;
+
+    fn to_chalk(self, db: &dyn HirDatabase) -> Self::Chalk {
+        match self.interned() {
+            crate::GenericArgData::Ty(ty) => ty.clone().to_chalk(db).cast(&Interner),
+        }
+    }
+
+    fn from_chalk(db: &dyn HirDatabase, chalk: Self::Chalk) -> Self {
+        match chalk.interned() {
+            chalk_ir::GenericArgData::Ty(ty) => Ty::from_chalk(db, ty.clone()).cast(&Interner),
+            chalk_ir::GenericArgData::Lifetime(_) => unimplemented!(),
+            chalk_ir::GenericArgData::Const(_) => unimplemented!(),
+        }
+    }
+}
+
 impl ToChalk for Substitution {
     type Chalk = chalk_ir::Substitution<Interner>;
 
     fn to_chalk(self, db: &dyn HirDatabase) -> chalk_ir::Substitution<Interner> {
-        chalk_ir::Substitution::from_iter(&Interner, self.iter().map(|ty| ty.clone().to_chalk(db)))
+        chalk_ir::Substitution::from_iter(
+            &Interner,
+            self.iter(&Interner).map(|ty| ty.clone().to_chalk(db)),
+        )
     }
 
     fn from_chalk(
         db: &dyn HirDatabase,
         parameters: chalk_ir::Substitution<Interner>,
     ) -> Substitution {
-        let tys = parameters
-            .iter(&Interner)
-            .map(|p| match p.ty(&Interner) {
-                Some(ty) => from_chalk(db, ty.clone()),
-                None => unimplemented!(),
-            })
-            .collect();
-        Substitution(tys)
+        let tys = parameters.iter(&Interner).map(|p| from_chalk(db, p.clone())).collect();
+        Substitution::intern(tys)
     }
 }
 
@@ -531,7 +544,7 @@ pub(super) fn generic_predicate_to_inline_bound(
                 // have the expected self type
                 return None;
             }
-            let args_no_self = trait_ref.substitution[1..]
+            let args_no_self = trait_ref.substitution.interned()[1..]
                 .iter()
                 .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
                 .collect();
@@ -543,7 +556,7 @@ pub(super) fn generic_predicate_to_inline_bound(
                 return None;
             }
             let trait_ = projection_ty.trait_(db);
-            let args_no_self = projection_ty.substitution[1..]
+            let args_no_self = projection_ty.substitution.interned()[1..]
                 .iter()
                 .map(|ty| ty.clone().to_chalk(db).cast(&Interner))
                 .collect();