5 files changed, 48 insertions, 43 deletions

diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 137419264..b1f98c507 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -7,7 +7,9 @@
 use chalk_ir::{Mutability, TyVariableKind};
 use hir_def::lang_item::LangItemTarget;
 
-use crate::{autoderef, traits::Solution, Interner, Obligation, Substs, TraitRef, Ty, TyKind};
+use crate::{
+    autoderef, traits::Solution, Interner, Obligation, Substitution, TraitRef, Ty, TyKind,
+};
 
 use super::{InEnvironment, InferenceContext};
 
@@ -134,7 +136,7 @@ impl<'a> InferenceContext<'a> {
             return None;
         }
 
-        let substs = Substs::build_for_generics(&generic_params)
+        let substs = Substitution::build_for_generics(&generic_params)
             .push(from_ty.clone())
             .push(to_ty.clone())
             .build();
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index f40dec17f..0be8c5a90 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -21,8 +21,8 @@ use crate::{
     to_assoc_type_id,
     traits::{chalk::from_chalk, FnTrait, InEnvironment},
     utils::{generics, variant_data, Generics},
-    AdtId, Binders, CallableDefId, FnPointer, FnSig, Interner, Obligation, Rawness, Scalar, Substs,
-    TraitRef, Ty, TyKind,
+    AdtId, Binders, CallableDefId, FnPointer, FnSig, Interner, Obligation, Rawness, Scalar,
+    Substitution, TraitRef, Ty, TyKind,
 };
 
 use super::{
@@ -77,7 +77,7 @@ impl<'a> InferenceContext<'a> {
             return None;
         }
 
-        let mut param_builder = Substs::builder(num_args);
+        let mut param_builder = Substitution::builder(num_args);
         let mut arg_tys = vec![];
         for _ in 0..num_args {
             let arg = self.table.new_type_var();
@@ -87,7 +87,7 @@ impl<'a> InferenceContext<'a> {
         let parameters = param_builder.build();
         let arg_ty = TyKind::Tuple(num_args, parameters).intern(&Interner);
         let substs =
-            Substs::build_for_generics(&generic_params).push(ty.clone()).push(arg_ty).build();
+            Substitution::build_for_generics(&generic_params).push(ty.clone()).push(arg_ty).build();
 
         let trait_env = Arc::clone(&self.trait_env);
         let implements_fn_trait =
@@ -181,7 +181,7 @@ impl<'a> InferenceContext<'a> {
                 let inner_ty = self.infer_expr(*body, &Expectation::none());
                 let impl_trait_id = crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, *body);
                 let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into();
-                TyKind::OpaqueType(opaque_ty_id, Substs::single(inner_ty)).intern(&Interner)
+                TyKind::OpaqueType(opaque_ty_id, Substitution::single(inner_ty)).intern(&Interner)
             }
             Expr::Loop { body, label } => {
                 self.breakables.push(BreakableContext {
@@ -262,12 +262,12 @@ impl<'a> InferenceContext<'a> {
                 let sig_ty = TyKind::Function(FnPointer {
                     num_args: sig_tys.len() - 1,
                     sig: FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: false },
-                    substs: Substs(sig_tys.clone().into()),
+                    substs: Substitution(sig_tys.clone().into()),
                 })
                 .intern(&Interner);
                 let closure_id = self.db.intern_closure((self.owner, tgt_expr)).into();
                 let closure_ty =
-                    TyKind::Closure(closure_id, Substs::single(sig_ty)).intern(&Interner);
+                    TyKind::Closure(closure_id, Substitution::single(sig_ty)).intern(&Interner);
 
                 // Eagerly try to relate the closure type with the expected
                 // type, otherwise we often won't have enough information to
@@ -402,7 +402,7 @@ impl<'a> InferenceContext<'a> {
 
                 self.unify(&ty, &expected.ty);
 
-                let substs = ty.substs().cloned().unwrap_or_else(Substs::empty);
+                let substs = ty.substs().cloned().unwrap_or_else(Substitution::empty);
                 let field_types = def_id.map(|it| self.db.field_types(it)).unwrap_or_default();
                 let variant_data = def_id.map(|it| variant_data(self.db.upcast(), it));
                 for field in fields.iter() {
@@ -511,7 +511,8 @@ impl<'a> InferenceContext<'a> {
             Expr::Box { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
                 if let Some(box_) = self.resolve_boxed_box() {
-                    let mut sb = Substs::builder(generics(self.db.upcast(), box_.into()).len());
+                    let mut sb =
+                        Substitution::builder(generics(self.db.upcast(), box_.into()).len());
                     sb = sb.push(inner_ty);
                     match self.db.generic_defaults(box_.into()).as_ref() {
                         [_, alloc_ty, ..] if !alloc_ty.value.is_unknown() => {
@@ -610,31 +611,31 @@ impl<'a> InferenceContext<'a> {
                 let rhs_ty = rhs.map(|e| self.infer_expr(e, &rhs_expect));
                 match (range_type, lhs_ty, rhs_ty) {
                     (RangeOp::Exclusive, None, None) => match self.resolve_range_full() {
-                        Some(adt) => Ty::adt_ty(adt, Substs::empty()),
+                        Some(adt) => Ty::adt_ty(adt, Substitution::empty()),
                         None => self.err_ty(),
                     },
                     (RangeOp::Exclusive, None, Some(ty)) => match self.resolve_range_to() {
-                        Some(adt) => Ty::adt_ty(adt, Substs::single(ty)),
+                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, None, Some(ty)) => {
                         match self.resolve_range_to_inclusive() {
-                            Some(adt) => Ty::adt_ty(adt, Substs::single(ty)),
+                            Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
                             None => self.err_ty(),
                         }
                     }
                     (RangeOp::Exclusive, Some(_), Some(ty)) => match self.resolve_range() {
-                        Some(adt) => Ty::adt_ty(adt, Substs::single(ty)),
+                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, Some(_), Some(ty)) => {
                         match self.resolve_range_inclusive() {
-                            Some(adt) => Ty::adt_ty(adt, Substs::single(ty)),
+                            Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
                             None => self.err_ty(),
                         }
                     }
                     (RangeOp::Exclusive, Some(ty), None) => match self.resolve_range_from() {
-                        Some(adt) => Ty::adt_ty(adt, Substs::single(ty)),
+                        Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
                         None => self.err_ty(),
                     },
                     (RangeOp::Inclusive, _, None) => self.err_ty(),
@@ -681,7 +682,7 @@ impl<'a> InferenceContext<'a> {
                     self.infer_expr_coerce(*expr, &Expectation::has_type(ty.clone()));
                 }
 
-                TyKind::Tuple(tys.len(), Substs(tys.into())).intern(&Interner)
+                TyKind::Tuple(tys.len(), Substitution(tys.into())).intern(&Interner)
             }
             Expr::Array(array) => {
                 let elem_ty = match expected.ty.interned(&Interner) {
@@ -887,7 +888,7 @@ impl<'a> InferenceContext<'a> {
         def_generics: Option<Generics>,
         generic_args: Option<&GenericArgs>,
         receiver_ty: &Ty,
-    ) -> Substs {
+    ) -> Substitution {
         let (parent_params, self_params, type_params, impl_trait_params) =
             def_generics.as_ref().map_or((0, 0, 0, 0), |g| g.provenance_split());
         assert_eq!(self_params, 0); // method shouldn't have another Self param
@@ -926,7 +927,7 @@ impl<'a> InferenceContext<'a> {
             substs.push(self.err_ty());
         }
         assert_eq!(substs.len(), total_len);
-        Substs(substs.into())
+        Substitution(substs.into())
     }
 
     fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
diff --git a/crates/hir_ty/src/infer/pat.rs b/crates/hir_ty/src/infer/pat.rs
index 9e8ca18ef..befa0d69b 100644
--- a/crates/hir_ty/src/infer/pat.rs
+++ b/crates/hir_ty/src/infer/pat.rs
@@ -12,7 +12,9 @@ use hir_def::{
 use hir_expand::name::Name;
 
 use super::{BindingMode, Expectation, InferenceContext};
-use crate::{lower::lower_to_chalk_mutability, utils::variant_data, Interner, Substs, Ty, TyKind};
+use crate::{
+    lower::lower_to_chalk_mutability, utils::variant_data, Interner, Substitution, Ty, TyKind,
+};
 
 impl<'a> InferenceContext<'a> {
     fn infer_tuple_struct_pat(
@@ -31,7 +33,7 @@ impl<'a> InferenceContext<'a> {
         }
         self.unify(&ty, expected);
 
-        let substs = ty.substs().cloned().unwrap_or_else(Substs::empty);
+        let substs = ty.substs().cloned().unwrap_or_else(Substitution::empty);
 
         let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         let (pre, post) = match ellipsis {
@@ -70,7 +72,7 @@ impl<'a> InferenceContext<'a> {
 
         self.unify(&ty, expected);
 
-        let substs = ty.substs().cloned().unwrap_or_else(Substs::empty);
+        let substs = ty.substs().cloned().unwrap_or_else(Substitution::empty);
 
         let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         for subpat in subpats {
@@ -138,7 +140,7 @@ impl<'a> InferenceContext<'a> {
                 inner_tys.extend(expectations_iter.by_ref().take(n_uncovered_patterns).cloned());
                 inner_tys.extend(post.iter().zip(expectations_iter).map(infer_pat));
 
-                TyKind::Tuple(inner_tys.len(), Substs(inner_tys.into())).intern(&Interner)
+                TyKind::Tuple(inner_tys.len(), Substitution(inner_tys.into())).intern(&Interner)
             }
             Pat::Or(ref pats) => {
                 if let Some((first_pat, rest)) = pats.split_first() {
@@ -237,7 +239,7 @@ impl<'a> InferenceContext<'a> {
                     };
 
                     let inner_ty = self.infer_pat(*inner, &inner_expected, default_bm);
-                    Ty::adt_ty(box_adt, Substs::single(inner_ty))
+                    Ty::adt_ty(box_adt, Substitution::single(inner_ty))
                 }
                 None => self.err_ty(),
             },
diff --git a/crates/hir_ty/src/infer/path.rs b/crates/hir_ty/src/infer/path.rs
index af108fb6c..ea01d6238 100644
--- a/crates/hir_ty/src/infer/path.rs
+++ b/crates/hir_ty/src/infer/path.rs
@@ -9,7 +9,7 @@ use hir_def::{
 };
 use hir_expand::name::Name;
 
-use crate::{method_resolution, Interner, Substs, Ty, TyKind, ValueTyDefId};
+use crate::{method_resolution, Interner, Substitution, Ty, TyKind, ValueTyDefId};
 
 use super::{ExprOrPatId, InferenceContext, TraitRef};
 
@@ -79,7 +79,7 @@ impl<'a> InferenceContext<'a> {
             }
             ValueNs::ImplSelf(impl_id) => {
                 let generics = crate::utils::generics(self.db.upcast(), impl_id.into());
-                let substs = Substs::type_params_for_generics(self.db, &generics);
+                let substs = Substitution::type_params_for_generics(self.db, &generics);
                 let ty = self.db.impl_self_ty(impl_id).subst(&substs);
                 if let Some((AdtId::StructId(struct_id), substs)) = ty.as_adt() {
                     let ty = self.db.value_ty(struct_id.into()).subst(&substs);
@@ -94,10 +94,10 @@ impl<'a> InferenceContext<'a> {
 
         let ty = self.db.value_ty(typable);
         // self_subst is just for the parent
-        let parent_substs = self_subst.unwrap_or_else(Substs::empty);
+        let parent_substs = self_subst.unwrap_or_else(Substitution::empty);
         let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver);
         let substs = ctx.substs_from_path(path, typable, true);
-        let full_substs = Substs::builder(substs.len())
+        let full_substs = Substitution::builder(substs.len())
             .use_parent_substs(&parent_substs)
             .fill(substs.0[parent_substs.len()..].iter().cloned())
             .build();
@@ -111,7 +111,7 @@ impl<'a> InferenceContext<'a> {
         path: &Path,
         remaining_index: usize,
         id: ExprOrPatId,
-    ) -> Option<(ValueNs, Option<Substs>)> {
+    ) -> Option<(ValueNs, Option<Substitution>)> {
         assert!(remaining_index < path.segments().len());
         // there may be more intermediate segments between the resolved one and
         // the end. Only the last segment needs to be resolved to a value; from
@@ -164,7 +164,7 @@ impl<'a> InferenceContext<'a> {
         trait_ref: TraitRef,
         segment: PathSegment<'_>,
         id: ExprOrPatId,
-    ) -> Option<(ValueNs, Option<Substs>)> {
+    ) -> Option<(ValueNs, Option<Substitution>)> {
         let trait_ = trait_ref.trait_;
         let item =
             self.db.trait_data(trait_).items.iter().map(|(_name, id)| (*id)).find_map(|item| {
@@ -208,7 +208,7 @@ impl<'a> InferenceContext<'a> {
         ty: Ty,
         name: &Name,
         id: ExprOrPatId,
-    ) -> Option<(ValueNs, Option<Substs>)> {
+    ) -> Option<(ValueNs, Option<Substitution>)> {
         if let TyKind::Unknown = ty.interned(&Interner) {
             return None;
         }
@@ -241,7 +241,7 @@ impl<'a> InferenceContext<'a> {
                 };
                 let substs = match container {
                     AssocContainerId::ImplId(impl_id) => {
-                        let impl_substs = Substs::build_for_def(self.db, impl_id)
+                        let impl_substs = Substitution::build_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).subst(&impl_substs);
@@ -250,7 +250,7 @@ impl<'a> InferenceContext<'a> {
                     }
                     AssocContainerId::TraitId(trait_) => {
                         // we're picking this method
-                        let trait_substs = Substs::build_for_def(self.db, trait_)
+                        let trait_substs = Substitution::build_for_def(self.db, trait_)
                             .push(ty.clone())
                             .fill(std::iter::repeat_with(|| self.table.new_type_var()))
                             .build();
@@ -274,7 +274,7 @@ impl<'a> InferenceContext<'a> {
         ty: &Ty,
         name: &Name,
         id: ExprOrPatId,
-    ) -> Option<(ValueNs, Option<Substs>)> {
+    ) -> Option<(ValueNs, Option<Substitution>)> {
         let (enum_id, subst) = match ty.as_adt() {
             Some((AdtId::EnumId(e), subst)) => (e, subst),
             _ => return None,
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index 7795f446f..b2d4f67b3 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -8,7 +8,7 @@ use ena::unify::{InPlaceUnificationTable, NoError, UnifyKey, UnifyValue};
 use super::{InferenceContext, Obligation};
 use crate::{
     BoundVar, Canonical, DebruijnIndex, FnPointer, GenericPredicate, InEnvironment, InferenceVar,
-    Interner, Scalar, Substs, Ty, TyKind, TypeWalk,
+    Interner, Scalar, Substitution, Ty, TyKind, TypeWalk,
 };
 
 impl<'a> InferenceContext<'a> {
@@ -123,10 +123,10 @@ impl<T> Canonicalized<T> {
     pub(super) fn apply_solution(
         &self,
         ctx: &mut InferenceContext<'_>,
-        solution: Canonical<Substs>,
+        solution: Canonical<Substitution>,
     ) {
         // the solution may contain new variables, which we need to convert to new inference vars
-        let new_vars = Substs(
+        let new_vars = Substitution(
             solution
                 .kinds
                 .iter()
@@ -147,9 +147,9 @@ impl<T> Canonicalized<T> {
     }
 }
 
-pub(crate) fn unify(tys: &Canonical<(Ty, Ty)>) -> Option<Substs> {
+pub(crate) fn unify(tys: &Canonical<(Ty, Ty)>) -> Option<Substitution> {
     let mut table = InferenceTable::new();
-    let vars = Substs(
+    let vars = Substitution(
         tys.kinds
             .iter()
             // we always use type vars here because we want everything to
@@ -173,7 +173,7 @@ pub(crate) fn unify(tys: &Canonical<(Ty, Ty)>) -> Option<Substs> {
         }
     }
     Some(
-        Substs::builder(tys.kinds.len())
+        Substitution::builder(tys.kinds.len())
             .fill(vars.iter().map(|v| table.resolve_ty_completely(v.clone())))
             .build(),
     )
@@ -264,8 +264,8 @@ impl InferenceTable {
 
     pub(crate) fn unify_substs(
         &mut self,
-        substs1: &Substs,
-        substs2: &Substs,
+        substs1: &Substitution,
+        substs2: &Substitution,
         depth: usize,
     ) -> bool {
         substs1.0.iter().zip(substs2.0.iter()).all(|(t1, t2)| self.unify_inner(t1, t2, depth))