14 files changed, 20 insertions, 69 deletions

diff --git a/crates/hir_ty/src/builder.rs b/crates/hir_ty/src/builder.rs
index 9a698898b..e25ef866d 100644
--- a/crates/hir_ty/src/builder.rs
+++ b/crates/hir_ty/src/builder.rs
@@ -14,7 +14,7 @@ use smallvec::SmallVec;
 use crate::{
     db::HirDatabase, primitive, to_assoc_type_id, to_chalk_trait_id, utils::generics, Binders,
     CallableSig, FnPointer, FnSig, FnSubst, GenericArg, Interner, ProjectionTy, Substitution,
-    TraitRef, Ty, TyDefId, TyExt, TyKind, TypeWalk, ValueTyDefId,
+    TraitRef, Ty, TyDefId, TyExt, TyKind, ValueTyDefId,
 };
 
 /// This is a builder for `Ty` or anything that needs a `Substitution`.
diff --git a/crates/hir_ty/src/chalk_cast.rs b/crates/hir_ty/src/chalk_cast.rs
index 8bdd32ad6..f27dee3fd 100644
--- a/crates/hir_ty/src/chalk_cast.rs
+++ b/crates/hir_ty/src/chalk_cast.rs
@@ -1,14 +1,8 @@
 //! Implementations of the Chalk `Cast` trait for our types.
 
-use chalk_ir::{
-    cast::{Cast, CastTo},
-    interner::HasInterner,
-};
+use chalk_ir::interner::HasInterner;
 
-use crate::{
-    AliasEq, CallableSig, DomainGoal, GenericArg, GenericArgData, Interner, PolyFnSig,
-    ReturnTypeImplTraits, TraitRef, Ty, WhereClause,
-};
+use crate::{CallableSig, ReturnTypeImplTraits};
 
 macro_rules! has_interner {
     ($t:ty) => {
@@ -18,15 +12,5 @@ macro_rules! has_interner {
     };
 }
 
-macro_rules! transitive_impl {
-    ($a:ty, $b:ty, $c:ty) => {
-        impl CastTo<$c> for $a {
-            fn cast_to(self, interner: &Interner) -> $c {
-                self.cast::<$b>(interner).cast(interner)
-            }
-        }
-    };
-}
-
 has_interner!(CallableSig);
 has_interner!(ReturnTypeImplTraits);
diff --git a/crates/hir_ty/src/infer.rs b/crates/hir_ty/src/infer.rs
index 1d8184ef5..bf2da2d4a 100644
--- a/crates/hir_ty/src/infer.rs
+++ b/crates/hir_ty/src/infer.rs
@@ -38,7 +38,6 @@ use syntax::SmolStr;
 
 use super::{
     DomainGoal, Guidance, InEnvironment, ProjectionTy, Solution, TraitEnvironment, TraitRef, Ty,
-    TypeWalk,
 };
 use crate::{
     db::HirDatabase, fold_tys, infer::diagnostics::InferenceDiagnostic,
diff --git a/crates/hir_ty/src/infer/coerce.rs b/crates/hir_ty/src/infer/coerce.rs
index 26dc6ceba..1f463a425 100644
--- a/crates/hir_ty/src/infer/coerce.rs
+++ b/crates/hir_ty/src/infer/coerce.rs
@@ -73,11 +73,11 @@ impl<'a> InferenceContext<'a> {
         // Pointer weakening and function to pointer
         match (from_ty.kind(&Interner), to_ty.kind(&Interner)) {
             // `*mut T` -> `*const T`
-            (TyKind::Raw(m1, inner), TyKind::Raw(m2 @ Mutability::Not, ..)) => {
+            (TyKind::Raw(_, inner), TyKind::Raw(m2 @ Mutability::Not, ..)) => {
                 from_ty = TyKind::Raw(*m2, inner.clone()).intern(&Interner);
             }
             // `&mut T` -> `&T`
-            (TyKind::Ref(m1, lt, inner), TyKind::Ref(m2 @ Mutability::Not, ..)) => {
+            (TyKind::Ref(_, lt, inner), TyKind::Ref(m2 @ Mutability::Not, ..)) => {
                 from_ty = TyKind::Ref(*m2, lt.clone(), inner.clone()).intern(&Interner);
             }
             // `&T` -> `*const T`
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index 5f03079e8..cbbfa8b5c 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -24,7 +24,6 @@ use crate::{
     utils::{generics, Generics},
     AdtId, Binders, CallableDefId, FnPointer, FnSig, FnSubst, InEnvironment, Interner,
     ProjectionTyExt, Rawness, Scalar, Substitution, TraitRef, Ty, TyBuilder, TyExt, TyKind,
-    TypeWalk,
 };
 
 use super::{
diff --git a/crates/hir_ty/src/infer/unify.rs b/crates/hir_ty/src/infer/unify.rs
index 3b9c4a495..a887e20b0 100644
--- a/crates/hir_ty/src/infer/unify.rs
+++ b/crates/hir_ty/src/infer/unify.rs
@@ -12,7 +12,7 @@ use super::{DomainGoal, InferenceContext};
 use crate::{
     fold_tys, static_lifetime, AliasEq, AliasTy, BoundVar, Canonical, CanonicalVarKinds,
     DebruijnIndex, FnPointer, FnSubst, InEnvironment, InferenceVar, Interner, Scalar, Substitution,
-    Ty, TyExt, TyKind, TypeWalk, WhereClause,
+    Ty, TyExt, TyKind, WhereClause,
 };
 
 impl<'a> InferenceContext<'a> {
diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index f7af8b8aa..874c95411 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -1,8 +1,6 @@
 //! The type system. We currently use this to infer types for completion, hover
 //! information and various assists.
 
-#![allow(unused)]
-
 #[allow(unused)]
 macro_rules! eprintln {
     ($($tt:tt)*) => { stdx::eprintln!($($tt)*) };
@@ -34,7 +32,6 @@ use std::sync::Arc;
 
 use base_db::salsa;
 use chalk_ir::{
-    cast::{CastTo, Caster},
     fold::{Fold, Shift},
     interner::HasInterner,
     UintTy,
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 6584bcf34..8a22d9ea3 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -35,7 +35,7 @@ use crate::{
     AliasEq, AliasTy, Binders, BoundVar, CallableSig, DebruijnIndex, DynTy, FnPointer, FnSig,
     FnSubst, ImplTraitId, OpaqueTy, PolyFnSig, ProjectionTy, QuantifiedWhereClause,
     QuantifiedWhereClauses, ReturnTypeImplTrait, ReturnTypeImplTraits, Substitution,
-    TraitEnvironment, TraitRef, TraitRefExt, Ty, TyBuilder, TyKind, TypeWalk, WhereClause,
+    TraitEnvironment, TraitRef, TraitRefExt, Ty, TyBuilder, TyKind, WhereClause,
 };
 
 #[derive(Debug)]
diff --git a/crates/hir_ty/src/method_resolution.rs b/crates/hir_ty/src/method_resolution.rs
index 766880b14..be3e4f09a 100644
--- a/crates/hir_ty/src/method_resolution.rs
+++ b/crates/hir_ty/src/method_resolution.rs
@@ -6,11 +6,7 @@ use std::{iter, sync::Arc};
 
 use arrayvec::ArrayVec;
 use base_db::CrateId;
-use chalk_ir::{
-    cast::Cast,
-    fold::{Fold, Folder},
-    Fallible, Mutability, UniverseIndex,
-};
+use chalk_ir::{cast::Cast, Mutability, UniverseIndex};
 use hir_def::{
     lang_item::LangItemTarget, nameres::DefMap, AssocContainerId, AssocItemId, FunctionId,
     GenericDefId, HasModule, ImplId, Lookup, ModuleId, TraitId,
@@ -25,9 +21,9 @@ use crate::{
     primitive::{self, FloatTy, IntTy, UintTy},
     static_lifetime,
     utils::all_super_traits,
-    AdtId, BoundVar, Canonical, CanonicalVarKinds, DebruijnIndex, FnPointer, FnSig, ForeignDefId,
+    AdtId, Canonical, CanonicalVarKinds, DebruijnIndex, FnPointer, FnSig, ForeignDefId,
     InEnvironment, Interner, Scalar, Substitution, TraitEnvironment, TraitRefExt, Ty, TyBuilder,
-    TyExt, TyKind, TypeWalk,
+    TyExt, TyKind,
 };
 
 /// This is used as a key for indexing impls.
diff --git a/crates/hir_ty/src/traits.rs b/crates/hir_ty/src/traits.rs
index 63d87fe61..1cda72d22 100644
--- a/crates/hir_ty/src/traits.rs
+++ b/crates/hir_ty/src/traits.rs
@@ -12,7 +12,7 @@ use crate::{
     Solution, TraitRefExt, Ty, TyKind, WhereClause,
 };
 
-use self::chalk::{from_chalk, Interner, ToChalk};
+use self::chalk::Interner;
 
 pub(crate) mod chalk;
 
@@ -101,8 +101,7 @@ pub(crate) fn trait_solve_query(
     // We currently don't deal with universes (I think / hope they're not yet
     // relevant for our use cases?)
     let u_canonical = chalk_ir::UCanonical { canonical, universes: 1 };
-    let solution = solve(db, krate, &u_canonical);
-    solution.map(|solution| solution_from_chalk(db, solution))
+    solve(db, krate, &u_canonical)
 }
 
 fn solve(
@@ -170,13 +169,6 @@ fn is_chalk_print() -> bool {
     std::env::var("CHALK_PRINT").is_ok()
 }
 
-fn solution_from_chalk(
-    db: &dyn HirDatabase,
-    solution: chalk_solve::Solution<Interner>,
-) -> Solution {
-    solution
-}
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub enum FnTrait {
     FnOnce,
diff --git a/crates/hir_ty/src/traits/chalk.rs b/crates/hir_ty/src/traits/chalk.rs
index e2a54fd92..b8c390b2e 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, interner::HasInterner, CanonicalVarKinds};
+use chalk_ir::{fold::shift::Shift, CanonicalVarKinds};
 use chalk_solve::rust_ir::{self, OpaqueTyDatumBound, WellKnownTrait};
 
 use base_db::{salsa::InternKey, CrateId};
diff --git a/crates/hir_ty/src/traits/chalk/mapping.rs b/crates/hir_ty/src/traits/chalk/mapping.rs
index 4abc0fbf2..7818f6387 100644
--- a/crates/hir_ty/src/traits/chalk/mapping.rs
+++ b/crates/hir_ty/src/traits/chalk/mapping.rs
@@ -3,16 +3,15 @@
 //! Chalk (in both directions); plus some helper functions for more specialized
 //! conversions.
 
-use chalk_ir::{cast::Cast, interner::HasInterner};
+use chalk_ir::cast::Cast;
 use chalk_solve::rust_ir;
 
 use base_db::salsa::InternKey;
 use hir_def::{GenericDefId, TypeAliasId};
 
 use crate::{
-    db::HirDatabase, static_lifetime, AliasTy, CallableDefId, Canonical, ConstrainedSubst,
-    DomainGoal, FnPointer, GenericArg, InEnvironment, OpaqueTy, ProjectionTy, ProjectionTyExt,
-    QuantifiedWhereClause, Substitution, TraitRef, Ty, TypeWalk, WhereClause,
+    db::HirDatabase, AliasTy, CallableDefId, ProjectionTyExt, QuantifiedWhereClause, Substitution,
+    Ty, WhereClause,
 };
 
 use super::interner::*;
diff --git a/crates/hir_ty/src/utils.rs b/crates/hir_ty/src/utils.rs
index d26f5152c..5f6cb052a 100644
--- a/crates/hir_ty/src/utils.rs
+++ b/crates/hir_ty/src/utils.rs
@@ -1,6 +1,5 @@
 //! Helper functions for working with def, which don't need to be a separate
 //! query, but can't be computed directly from `*Data` (ie, which need a `db`).
-use std::sync::Arc;
 
 use chalk_ir::{fold::Shift, BoundVar, DebruijnIndex};
 use hir_def::{
@@ -16,9 +15,7 @@ use hir_def::{
 };
 use hir_expand::name::{name, Name};
 
-use crate::{
-    db::HirDatabase, Interner, Substitution, TraitRef, TraitRefExt, TyKind, TypeWalk, WhereClause,
-};
+use crate::{db::HirDatabase, Interner, Substitution, TraitRef, TraitRefExt, TyKind, WhereClause};
 
 fn direct_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
     let resolver = trait_.resolver(db);
@@ -137,15 +134,6 @@ pub(super) fn associated_type_by_name_including_super_traits(
     })
 }
 
-/// Helper for mutating `Arc<[T]>` (i.e. `Arc::make_mut` for Arc slices).
-/// The underlying values are cloned if there are other strong references.
-pub(crate) fn make_mut_slice<T: Clone>(a: &mut Arc<[T]>) -> &mut [T] {
-    if Arc::get_mut(a).is_none() {
-        *a = a.iter().cloned().collect();
-    }
-    Arc::get_mut(a).unwrap()
-}
-
 pub(crate) fn generics(db: &dyn DefDatabase, def: GenericDefId) -> Generics {
     let parent_generics = parent_generic_def(db, def).map(|def| Box::new(generics(db, def)));
     Generics { def, params: db.generic_params(def), parent_generics }
diff --git a/crates/hir_ty/src/walk.rs b/crates/hir_ty/src/walk.rs
index 57343fd61..6ef1d5336 100644
--- a/crates/hir_ty/src/walk.rs
+++ b/crates/hir_ty/src/walk.rs
@@ -1,14 +1,11 @@
 //! The `TypeWalk` trait (probably to be replaced by Chalk's `Fold` and
 //! `Visit`).
 
-use std::mem;
-
-use chalk_ir::{interner::HasInterner, DebruijnIndex};
+use chalk_ir::interner::HasInterner;
 
 use crate::{
-    utils::make_mut_slice, AliasEq, AliasTy, Binders, CallableSig, FnSubst, GenericArg,
-    GenericArgData, Interner, OpaqueTy, ProjectionTy, Substitution, TraitRef, Ty, TyKind,
-    WhereClause,
+    AliasEq, AliasTy, Binders, CallableSig, FnSubst, GenericArg, GenericArgData, Interner,
+    OpaqueTy, ProjectionTy, Substitution, TraitRef, Ty, TyKind, WhereClause,
 };
 
 /// This allows walking structures that contain types to do something with those