14 files changed, 52 insertions, 43 deletions

diff --git a/crates/hir/src/display.rs b/crates/hir/src/display.rs
index d4e477a85..01a4d205f 100644
--- a/crates/hir/src/display.rs
+++ b/crates/hir/src/display.rs
@@ -9,6 +9,7 @@ use hir_ty::display::{
     write_bounds_like_dyn_trait_with_prefix, write_visibility, HirDisplay, HirDisplayError,
     HirFormatter,
 };
+use hir_ty::Interner;
 use syntax::ast::{self, NameOwner};
 
 use crate::{
@@ -235,7 +236,8 @@ impl HirDisplay for TypeParam {
         write!(f, "{}", self.name(f.db))?;
         let bounds = f.db.generic_predicates_for_param(self.id);
         let substs = TyBuilder::type_params_subst(f.db, self.id.parent);
-        let predicates = bounds.iter().cloned().map(|b| b.substitute(&substs)).collect::<Vec<_>>();
+        let predicates =
+            bounds.iter().cloned().map(|b| b.substitute(&Interner, &substs)).collect::<Vec<_>>();
         if !(predicates.is_empty() || f.omit_verbose_types()) {
             write_bounds_like_dyn_trait_with_prefix(":", &predicates, f)?;
         }
diff --git a/crates/hir/src/lib.rs b/crates/hir/src/lib.rs
index add1b55c2..003821981 100644
--- a/crates/hir/src/lib.rs
+++ b/crates/hir/src/lib.rs
@@ -516,7 +516,7 @@ impl Field {
             VariantDef::Variant(it) => it.parent.id.into(),
         };
         let substs = TyBuilder::type_params_subst(db, generic_def_id);
-        let ty = db.field_types(var_id)[self.id].clone().substitute(&substs);
+        let ty = db.field_types(var_id)[self.id].clone().substitute(&Interner, &substs);
         Type::new(db, self.parent.module(db).id.krate(), var_id, ty)
     }
 
@@ -1503,7 +1503,7 @@ impl TypeParam {
         let krate = self.id.parent.module(db.upcast()).krate();
         let ty = params.get(local_idx)?.clone();
         let subst = TyBuilder::type_params_subst(db, self.id.parent);
-        let ty = ty.substitute(&subst.prefix(local_idx));
+        let ty = ty.substitute(&Interner, &subst.prefix(local_idx));
         Some(Type::new_with_resolver_inner(db, krate, &resolver, ty))
     }
 }
@@ -1916,7 +1916,7 @@ impl Type {
             .iter()
             .map(|(local_id, ty)| {
                 let def = Field { parent: variant_id.into(), id: local_id };
-                let ty = ty.clone().substitute(substs);
+                let ty = ty.clone().substitute(&Interner, substs);
                 (def, self.derived(ty))
             })
             .collect()
diff --git a/crates/hir/src/source_analyzer.rs b/crates/hir/src/source_analyzer.rs
index 82807ea09..4ce1c2080 100644
--- a/crates/hir/src/source_analyzer.rs
+++ b/crates/hir/src/source_analyzer.rs
@@ -20,7 +20,7 @@ use hir_def::{
 use hir_expand::{hygiene::Hygiene, name::AsName, HirFileId, InFile};
 use hir_ty::{
     diagnostics::{record_literal_missing_fields, record_pattern_missing_fields},
-    InferenceResult, Substitution, TyLoweringContext,
+    InferenceResult, Interner, Substitution, TyLoweringContext,
 };
 use syntax::{
     ast::{self, AstNode},
@@ -339,7 +339,7 @@ impl SourceAnalyzer {
             .into_iter()
             .map(|local_id| {
                 let field = FieldId { parent: variant, local_id };
-                let ty = field_types[local_id].clone().substitute(substs);
+                let ty = field_types[local_id].clone().substitute(&Interner, substs);
                 (field.into(), Type::new_with_resolver_inner(db, krate, &self.resolver, ty))
             })
             .collect()
diff --git a/crates/hir_ty/src/builder.rs b/crates/hir_ty/src/builder.rs
index c5196200c..9b2c6975a 100644
--- a/crates/hir_ty/src/builder.rs
+++ b/crates/hir_ty/src/builder.rs
@@ -139,7 +139,8 @@ impl TyBuilder<hir_def::AdtId> {
             } else {
                 // each default can depend on the previous parameters
                 let subst_so_far = Substitution::intern(self.vec.clone());
-                self.vec.push(default_ty.clone().substitute(&subst_so_far).cast(&Interner));
+                self.vec
+                    .push(default_ty.clone().substitute(&Interner, &subst_so_far).cast(&Interner));
             }
         }
         self
@@ -200,7 +201,7 @@ impl<T: TypeWalk + HasInterner<Interner = Interner>> TyBuilder<Binders<T>> {
 
     pub fn build(self) -> T {
         let (b, subst) = self.build_internal();
-        b.substitute(&subst)
+        b.substitute(&Interner, &subst)
     }
 }
 
diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index 704504b02..f31e6b108 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -352,7 +352,7 @@ impl HirDisplay for Ty {
                             let data = (*datas)
                                 .as_ref()
                                 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
-                            let bounds = data.substitute(parameters);
+                            let bounds = data.substitute(&Interner, parameters);
                             bounds.into_value_and_skipped_binders().0
                         } else {
                             Vec::new()
@@ -397,7 +397,7 @@ impl HirDisplay for Ty {
             }
             TyKind::FnDef(def, parameters) => {
                 let def = from_chalk(f.db, *def);
-                let sig = f.db.callable_item_signature(def).substitute(parameters);
+                let sig = f.db.callable_item_signature(def).substitute(&Interner, parameters);
                 match def {
                     CallableDefId::FunctionId(ff) => {
                         write!(f, "fn {}", f.db.function_data(ff).name)?
@@ -482,7 +482,7 @@ impl HirDisplay for Ty {
                                         (_, Some(default_parameter)) => {
                                             let actual_default = default_parameter
                                                 .clone()
-                                                .substitute(&parameters.prefix(i));
+                                                .substitute(&Interner, &parameters.prefix(i));
                                             if parameter.assert_ty_ref(&Interner) != &actual_default
                                             {
                                                 default_from = i + 1;
@@ -542,7 +542,7 @@ impl HirDisplay for Ty {
                         let data = (*datas)
                             .as_ref()
                             .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
-                        let bounds = data.substitute(&parameters);
+                        let bounds = data.substitute(&Interner, &parameters);
                         write_bounds_like_dyn_trait_with_prefix("impl", bounds.skip_binders(), f)?;
                         // FIXME: it would maybe be good to distinguish this from the alias type (when debug printing), and to show the substitution
                     }
@@ -595,7 +595,7 @@ impl HirDisplay for Ty {
                         let bounds =
                             f.db.generic_predicates(id.parent)
                                 .into_iter()
-                                .map(|pred| pred.clone().substitute(&substs))
+                                .map(|pred| pred.clone().substitute(&Interner, &substs))
                                 .filter(|wc| match &wc.skip_binders() {
                                     WhereClause::Implemented(tr) => {
                                         tr.self_type_parameter(&Interner) == self
@@ -629,7 +629,7 @@ impl HirDisplay for Ty {
                         let data = (*datas)
                             .as_ref()
                             .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
-                        let bounds = data.substitute(&opaque_ty.substitution);
+                        let bounds = data.substitute(&Interner, &opaque_ty.substitution);
                         write_bounds_like_dyn_trait_with_prefix("impl", bounds.skip_binders(), f)?;
                     }
                     ImplTraitId::AsyncBlockTypeImplTrait(..) => {
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index a87037344..1c3faf5cb 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -470,25 +470,25 @@ impl<'a> InferenceContext<'a> {
             TypeNs::AdtId(AdtId::StructId(strukt)) => {
                 let substs = ctx.substs_from_path(path, strukt.into(), true);
                 let ty = self.db.ty(strukt.into());
-                let ty = self.insert_type_vars(ty.substitute(&substs));
+                let ty = self.insert_type_vars(ty.substitute(&Interner, &substs));
                 forbid_unresolved_segments((ty, Some(strukt.into())), unresolved)
             }
             TypeNs::AdtId(AdtId::UnionId(u)) => {
                 let substs = ctx.substs_from_path(path, u.into(), true);
                 let ty = self.db.ty(u.into());
-                let ty = self.insert_type_vars(ty.substitute(&substs));
+                let ty = self.insert_type_vars(ty.substitute(&Interner, &substs));
                 forbid_unresolved_segments((ty, Some(u.into())), unresolved)
             }
             TypeNs::EnumVariantId(var) => {
                 let substs = ctx.substs_from_path(path, var.into(), true);
                 let ty = self.db.ty(var.parent.into());
-                let ty = self.insert_type_vars(ty.substitute(&substs));
+                let ty = self.insert_type_vars(ty.substitute(&Interner, &substs));
                 forbid_unresolved_segments((ty, Some(var.into())), unresolved)
             }
             TypeNs::SelfType(impl_id) => {
                 let generics = crate::utils::generics(self.db.upcast(), impl_id.into());
                 let substs = generics.type_params_subst(self.db);
-                let ty = self.db.impl_self_ty(impl_id).substitute(&substs);
+                let ty = self.db.impl_self_ty(impl_id).substitute(&Interner, &substs);
                 match unresolved {
                     None => {
                         let variant = ty_variant(&ty);
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 5f8ad2174..6966d26e7 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -419,7 +419,7 @@ impl<'a> InferenceContext<'a> {
                         self.result.record_field_resolutions.insert(field.expr, field_def);
                     }
                     let field_ty = field_def.map_or(self.err_ty(), |it| {
-                        field_types[it.local_id].clone().substitute(&substs)
+                        field_types[it.local_id].clone().substitute(&Interner, &substs)
                     });
                     self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty));
                 }
@@ -462,7 +462,7 @@ impl<'a> InferenceContext<'a> {
                                 Some(
                                     self.db.field_types((*s).into())[field.local_id]
                                         .clone()
-                                        .substitute(&parameters),
+                                        .substitute(&Interner, &parameters),
                                 )
                             } else {
                                 None
@@ -476,7 +476,7 @@ impl<'a> InferenceContext<'a> {
                                 Some(
                                     self.db.field_types((*u).into())[field.local_id]
                                         .clone()
-                                        .substitute(&parameters),
+                                        .substitute(&Interner, &parameters),
                                 )
                             } else {
                                 None
@@ -852,7 +852,7 @@ impl<'a> InferenceContext<'a> {
             None => (receiver_ty, Binders::empty(&Interner, self.err_ty()), None),
         };
         let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
-        let method_ty = method_ty.substitute(&substs);
+        let method_ty = method_ty.substitute(&Interner, &substs);
         let method_ty = self.insert_type_vars(method_ty);
         self.register_obligations_for_call(&method_ty);
         let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
@@ -949,8 +949,10 @@ impl<'a> InferenceContext<'a> {
             let def: CallableDefId = from_chalk(self.db, *fn_def);
             let generic_predicates = self.db.generic_predicates(def.into());
             for predicate in generic_predicates.iter() {
-                let (predicate, binders) =
-                    predicate.clone().substitute(parameters).into_value_and_skipped_binders();
+                let (predicate, binders) = predicate
+                    .clone()
+                    .substitute(&Interner, parameters)
+                    .into_value_and_skipped_binders();
                 always!(binders.len(&Interner) == 0); // quantified where clauses not yet handled
                 self.push_obligation(predicate.cast(&Interner));
             }
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index b74f1f4f8..252ae914a 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -49,7 +49,9 @@ impl<'a> InferenceContext<'a> {
             let expected_ty = var_data
                 .as_ref()
                 .and_then(|d| d.field(&Name::new_tuple_field(i)))
-                .map_or(self.err_ty(), |field| field_tys[field].clone().substitute(&substs));
+                .map_or(self.err_ty(), |field| {
+                    field_tys[field].clone().substitute(&Interner, &substs)
+                });
             let expected_ty = self.normalize_associated_types_in(expected_ty);
             self.infer_pat(subpat, &expected_ty, default_bm);
         }
@@ -83,8 +85,9 @@ impl<'a> InferenceContext<'a> {
                 self.result.record_pat_field_resolutions.insert(subpat.pat, field_def);
             }
 
-            let expected_ty = matching_field
-                .map_or(self.err_ty(), |field| field_tys[field].clone().substitute(&substs));
+            let expected_ty = matching_field.map_or(self.err_ty(), |field| {
+                field_tys[field].clone().substitute(&Interner, &substs)
+            });
             let expected_ty = self.normalize_associated_types_in(expected_ty);
             self.infer_pat(subpat.pat, &expected_ty, default_bm);
         }
diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index 5e3a45766..14f705173 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -81,9 +81,9 @@ impl<'a> InferenceContext<'a> {
             ValueNs::ImplSelf(impl_id) => {
                 let generics = crate::utils::generics(self.db.upcast(), impl_id.into());
                 let substs = generics.type_params_subst(self.db);
-                let ty = self.db.impl_self_ty(impl_id).substitute(&substs);
+                let ty = self.db.impl_self_ty(impl_id).substitute(&Interner, &substs);
                 if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
-                    let ty = self.db.value_ty(struct_id.into()).substitute(&substs);
+                    let ty = self.db.value_ty(struct_id.into()).substitute(&Interner, &substs);
                     return Some(ty);
                 } else {
                     // FIXME: diagnostic, invalid Self reference
@@ -243,7 +243,8 @@ impl<'a> InferenceContext<'a> {
                         let impl_substs = TyBuilder::subst_for_def(self.db, impl_id)
                             .fill(iter::repeat_with(|| self.table.new_type_var()))
                             .build();
-                        let impl_self_ty = self.db.impl_self_ty(impl_id).substitute(&impl_substs);
+                        let impl_self_ty =
+                            self.db.impl_self_ty(impl_id).substitute(&Interner, &impl_substs);
                         self.unify(&impl_self_ty, &ty);
                         Some(impl_substs)
                     }
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index e15840c9a..827317fce 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -130,9 +130,9 @@ impl<T> Binders<T> {
 
 impl<T: TypeWalk> Binders<T> {
     /// Substitutes all variables.
-    pub fn substitute(self, subst: &Substitution) -> T {
+    pub fn substitute(self, interner: &Interner, subst: &Substitution) -> T {
         let (value, binders) = self.into_value_and_skipped_binders();
-        assert_eq!(subst.len(&Interner), binders.len(&Interner));
+        assert_eq!(subst.len(interner), binders.len(interner));
         value.subst_bound_vars(subst)
     }
 }
@@ -362,7 +362,7 @@ impl Ty {
             TyKind::FnDef(def, parameters) => {
                 let callable_def = db.lookup_intern_callable_def((*def).into());
                 let sig = db.callable_item_signature(callable_def);
-                Some(sig.substitute(&parameters))
+                Some(sig.substitute(&Interner, &parameters))
             }
             TyKind::Closure(.., substs) => {
                 let sig_param = substs.at(&Interner, 0).assert_ty_ref(&Interner);
@@ -436,7 +436,7 @@ impl Ty {
                             let data = (*it)
                                 .as_ref()
                                 .map(|rpit| rpit.impl_traits[idx as usize].bounds.clone());
-                            data.substitute(&opaque_ty.substitution)
+                            data.substitute(&Interner, &opaque_ty.substitution)
                         })
                     }
                     // It always has an parameter for Future::Output type.
@@ -455,7 +455,7 @@ impl Ty {
                         let predicates = db
                             .generic_predicates(id.parent)
                             .into_iter()
-                            .map(|pred| pred.clone().substitute(&substs))
+                            .map(|pred| pred.clone().substitute(&Interner, &substs))
                             .filter(|wc| match &wc.skip_binders() {
                                 WhereClause::Implemented(tr) => {
                                     tr.self_type_parameter(&Interner) == self
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 6a3a880e0..00838b298 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -414,7 +414,7 @@ impl<'a> TyLoweringContext<'a> {
                     TypeParamLoweringMode::Placeholder => generics.type_params_subst(self.db),
                     TypeParamLoweringMode::Variable => generics.bound_vars_subst(self.in_binders),
                 };
-                self.db.impl_self_ty(impl_id).substitute(&substs)
+                self.db.impl_self_ty(impl_id).substitute(&Interner, &substs)
             }
             TypeNs::AdtSelfType(adt) => {
                 let generics = generics(self.db.upcast(), adt.into());
@@ -422,7 +422,7 @@ impl<'a> TyLoweringContext<'a> {
                     TypeParamLoweringMode::Placeholder => generics.type_params_subst(self.db),
                     TypeParamLoweringMode::Variable => generics.bound_vars_subst(self.in_binders),
                 };
-                self.db.ty(adt.into()).substitute(&substs)
+                self.db.ty(adt.into()).substitute(&Interner, &substs)
             }
 
             TypeNs::AdtId(it) => self.lower_path_inner(resolved_segment, it.into(), infer_args),
@@ -516,7 +516,7 @@ impl<'a> TyLoweringContext<'a> {
             TyDefId::TypeAliasId(it) => Some(it.into()),
         };
         let substs = self.substs_from_path_segment(segment, generic_def, infer_args, None);
-        self.db.ty(typeable).substitute(&substs)
+        self.db.ty(typeable).substitute(&Interner, &substs)
     }
 
     /// Collect generic arguments from a path into a `Substs`. See also
@@ -620,7 +620,7 @@ impl<'a> TyLoweringContext<'a> {
                 for default_ty in defaults.iter().skip(substs.len()) {
                     // each default can depend on the previous parameters
                     let substs_so_far = Substitution::from_iter(&Interner, substs.clone());
-                    substs.push(default_ty.clone().substitute(&substs_so_far));
+                    substs.push(default_ty.clone().substitute(&Interner, &substs_so_far));
                 }
             }
         }
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index 88750acf3..19a1fa793 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -712,7 +712,7 @@ pub(crate) fn inherent_impl_substs(
     let vars = TyBuilder::subst_for_def(db, impl_id)
         .fill_with_bound_vars(DebruijnIndex::INNERMOST, self_ty.binders.len(&Interner))
         .build();
-    let self_ty_with_vars = db.impl_self_ty(impl_id).substitute(&vars);
+    let self_ty_with_vars = db.impl_self_ty(impl_id).substitute(&Interner, &vars);
     let mut kinds = self_ty.binders.interned().to_vec();
     kinds.extend(
         iter::repeat(chalk_ir::WithKind::new(
@@ -774,7 +774,7 @@ fn transform_receiver_ty(
         AssocContainerId::ModuleId(_) => unreachable!(),
     };
     let sig = db.callable_item_signature(function_id.into());
-    Some(sig.map(|s| s.params()[0].clone()).substitute(&substs))
+    Some(sig.map(|s| s.params()[0].clone()).substitute(&Interner, &substs))
 }
 
 pub fn implements_trait(
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index 481b0bb10..9db2b0c2f 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -519,7 +519,7 @@ pub(super) fn convert_where_clauses(
     let generic_predicates = db.generic_predicates(def);
     let mut result = Vec::with_capacity(generic_predicates.len());
     for pred in generic_predicates.iter() {
-        result.push(pred.clone().substitute(substs).to_chalk(db));
+        result.push(pred.clone().substitute(&Interner, substs).to_chalk(db));
     }
     result
 }
diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs
index a63075a19..c7786a199 100644
--- a/crates/hir_ty/src/utils.rs
+++ b/crates/hir_ty/src/utils.rs
@@ -72,7 +72,7 @@ fn direct_super_trait_refs(db: &dyn HirDatabase, trait_ref: &TraitRef) -> Vec<Tr
                 _ => None,
             })
         })
-        .map(|pred| pred.substitute(&trait_ref.substitution))
+        .map(|pred| pred.substitute(&Interner, &trait_ref.substitution))
         .collect()
 }