Merge #3220

3220: Fix clippy warnings, update Cargo.toml versions r=matklad a=SomeoneToIgnore

In the `cargo xtask lint` ouptut, there were two interesting Clippy warnings that might be interesting to investigate further:

* warning: this argument (4 byte) is passed by reference, but would be more efficient if passed by value (limit: 8 byte)

* warning: large size difference between variants

Co-authored-by: Kirill Bulatov <[email protected]>

18 files changed, 108 insertions, 134 deletions

diff --git a/crates/ra_hir_ty/Cargo.toml b/crates/ra_hir_ty/Cargo.toml
index f5484bf70..49cafc539 100644
--- a/crates/ra_hir_ty/Cargo.toml
+++ b/crates/ra_hir_ty/Cargo.toml
@@ -9,9 +9,9 @@ doctest = false
 
 [dependencies]
 arrayvec = "0.5.1"
-ena = "0.13"
-log = "0.4.5"
-rustc-hash = "1.0"
+ena = "0.13.1"
+log = "0.4.8"
+rustc-hash = "1.1.0"
 
 hir_def = { path = "../ra_hir_def", package = "ra_hir_def" }
 hir_expand = { path = "../ra_hir_expand", package = "ra_hir_expand" }
@@ -28,4 +28,4 @@ chalk-ir =      { git = "https://github.com/rust-lang/chalk.git", rev = "af48f30
 lalrpop-intern = "0.15.1"
 
 [dev-dependencies]
-insta = "0.13.0"
+insta = "0.13.1"
diff --git a/crates/ra_hir_ty/src/diagnostics.rs b/crates/ra_hir_ty/src/diagnostics.rs
index 5054189cc..6eafdc8f6 100644
--- a/crates/ra_hir_ty/src/diagnostics.rs
+++ b/crates/ra_hir_ty/src/diagnostics.rs
@@ -40,7 +40,7 @@ impl Diagnostic for MissingFields {
         use std::fmt::Write;
         let mut message = String::from("Missing structure fields:\n");
         for field in &self.missed_fields {
-            write!(message, "- {}\n", field).unwrap();
+            writeln!(message, "- {}", field).unwrap();
         }
         message
     }
diff --git a/crates/ra_hir_ty/src/expr.rs b/crates/ra_hir_ty/src/expr.rs
index f752a9f09..0d11b537c 100644
--- a/crates/ra_hir_ty/src/expr.rs
+++ b/crates/ra_hir_ty/src/expr.rs
@@ -138,7 +138,7 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             _ => return,
         };
 
-        if params.len() == 2 && &params[0] == &mismatch.actual {
+        if params.len() == 2 && params[0] == mismatch.actual {
             let (_, source_map) = db.body_with_source_map(self.func.into());
 
             if let Some(source_ptr) = source_map.expr_syntax(id) {
diff --git a/crates/ra_hir_ty/src/infer.rs b/crates/ra_hir_ty/src/infer.rs
index a9d958c8b..76069eb9c 100644
--- a/crates/ra_hir_ty/src/infer.rs
+++ b/crates/ra_hir_ty/src/infer.rs
@@ -225,14 +225,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             coerce_unsized_map: Self::init_coerce_unsized_map(db, &resolver),
             db,
             owner,
-            body: db.body(owner.into()),
+            body: db.body(owner),
             resolver,
         }
     }
 
     fn resolve_all(mut self) -> InferenceResult {
         // FIXME resolve obligations as well (use Guidance if necessary)
-        let mut result = mem::replace(&mut self.result, InferenceResult::default());
+        let mut result = std::mem::take(&mut self.result);
         for ty in result.type_of_expr.values_mut() {
             let resolved = self.table.resolve_ty_completely(mem::replace(ty, Ty::Unknown));
             *ty = resolved;
@@ -261,7 +261,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     }
 
     fn write_assoc_resolution(&mut self, id: ExprOrPatId, item: AssocItemId) {
-        self.result.assoc_resolutions.insert(id, item.into());
+        self.result.assoc_resolutions.insert(id, item);
     }
 
     fn write_pat_ty(&mut self, pat: PatId, ty: Ty) {
@@ -312,9 +312,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         for obligation in obligations {
             let in_env = InEnvironment::new(self.trait_env.clone(), obligation.clone());
             let canonicalized = self.canonicalizer().canonicalize_obligation(in_env);
-            let solution = self
-                .db
-                .trait_solve(self.resolver.krate().unwrap().into(), canonicalized.value.clone());
+            let solution =
+                self.db.trait_solve(self.resolver.krate().unwrap(), canonicalized.value.clone());
 
             match solution {
                 Some(Solution::Unique(substs)) => {
diff --git a/crates/ra_hir_ty/src/infer/coerce.rs b/crates/ra_hir_ty/src/infer/coerce.rs
index f68a1439f..fb6a51b12 100644
--- a/crates/ra_hir_ty/src/infer/coerce.rs
+++ b/crates/ra_hir_ty/src/infer/coerce.rs
@@ -26,7 +26,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     /// Note that it is only possible that one type are coerced to another.
     /// Coercing both types to another least upper bound type is not possible in rustc,
     /// which will simply result in "incompatible types" error.
-    pub(super) fn coerce_merge_branch<'t>(&mut self, ty1: &Ty, ty2: &Ty) -> Ty {
+    pub(super) fn coerce_merge_branch(&mut self, ty1: &Ty, ty2: &Ty) -> Ty {
         if self.coerce(ty1, ty2) {
             ty2.clone()
         } else if self.coerce(ty2, ty1) {
@@ -44,10 +44,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         resolver: &Resolver,
     ) -> FxHashMap<(TypeCtor, TypeCtor), usize> {
         let krate = resolver.krate().unwrap();
-        let impls = match db.lang_item(krate.into(), "coerce_unsized".into()) {
-            Some(LangItemTarget::TraitId(trait_)) => {
-                db.impls_for_trait(krate.into(), trait_.into())
-            }
+        let impls = match db.lang_item(krate, "coerce_unsized".into()) {
+            Some(LangItemTarget::TraitId(trait_)) => db.impls_for_trait(krate, trait_),
             _ => return FxHashMap::default(),
         };
 
@@ -254,15 +252,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 let unsize_generic_index = {
                     let mut index = None;
                     let mut multiple_param = false;
-                    field_tys[last_field_id].value.walk(&mut |ty| match ty {
-                        &Ty::Bound(idx) => {
+                    field_tys[last_field_id].value.walk(&mut |ty| {
+                        if let &Ty::Bound(idx) = ty {
                             if index.is_none() {
                                 index = Some(idx);
                             } else if Some(idx) != index {
                                 multiple_param = true;
                             }
                         }
-                        _ => {}
                     });
 
                     if multiple_param {
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index 39d8bc0ca..9d5f75625 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -35,8 +35,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() },
             );
         }
-        let ty = self.resolve_ty_as_possible(ty);
-        ty
+        self.resolve_ty_as_possible(ty)
     }
 
     /// Infer type of expression with possibly implicit coerce to the expected type.
@@ -127,10 +126,8 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     TypeCtor::FnPtr { num_args: sig_tys.len() as u16 - 1 },
                     Substs(sig_tys.into()),
                 );
-                let closure_ty = Ty::apply_one(
-                    TypeCtor::Closure { def: self.owner.into(), expr: tgt_expr },
-                    sig_ty,
-                );
+                let closure_ty =
+                    Ty::apply_one(TypeCtor::Closure { def: self.owner, expr: tgt_expr }, sig_ty);
 
                 // Eagerly try to relate the closure type with the expected
                 // type, otherwise we often won't have enough information to
@@ -157,15 +154,14 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 };
                 self.register_obligations_for_call(&callee_ty);
                 self.check_call_arguments(args, &param_tys);
-                let ret_ty = self.normalize_associated_types_in(ret_ty);
-                ret_ty
+                self.normalize_associated_types_in(ret_ty)
             }
             Expr::MethodCall { receiver, args, method_name, generic_args } => self
                 .infer_method_call(tgt_expr, *receiver, &args, &method_name, generic_args.as_ref()),
             Expr::Match { expr, arms } => {
                 let input_ty = self.infer_expr(*expr, &Expectation::none());
 
-                let mut result_ty = if arms.len() == 0 {
+                let mut result_ty = if arms.is_empty() {
                     Ty::simple(TypeCtor::Never)
                 } else {
                     self.table.new_type_var()
@@ -188,7 +184,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
             Expr::Path(p) => {
                 // FIXME this could be more efficient...
-                let resolver = resolver_for_expr(self.db, self.owner.into(), tgt_expr);
+                let resolver = resolver_for_expr(self.db, self.owner, tgt_expr);
                 self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(Ty::Unknown)
             }
             Expr::Continue => Ty::simple(TypeCtor::Never),
@@ -217,8 +213,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 self.unify(&ty, &expected.ty);
 
                 let substs = ty.substs().unwrap_or_else(Substs::empty);
-                let field_types =
-                    def_id.map(|it| self.db.field_types(it.into())).unwrap_or_default();
+                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, it));
                 for (field_idx, field) in fields.iter().enumerate() {
                     let field_def =
@@ -264,7 +259,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                             .and_then(|idx| a_ty.parameters.0.get(idx).cloned()),
                         TypeCtor::Adt(AdtId::StructId(s)) => {
                             self.db.struct_data(s).variant_data.field(name).map(|local_id| {
-                                let field = StructFieldId { parent: s.into(), local_id }.into();
+                                let field = StructFieldId { parent: s.into(), local_id };
                                 self.write_field_resolution(tgt_expr, field);
                                 self.db.field_types(s.into())[field.local_id]
                                     .clone()
@@ -283,14 +278,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             }
             Expr::Await { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
-                let ty =
-                    self.resolve_associated_type(inner_ty, self.resolve_future_future_output());
-                ty
+                self.resolve_associated_type(inner_ty, self.resolve_future_future_output())
             }
             Expr::Try { expr } => {
                 let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
-                let ty = self.resolve_associated_type(inner_ty, self.resolve_ops_try_ok());
-                ty
+                self.resolve_associated_type(inner_ty, self.resolve_ops_try_ok())
             }
             Expr::Cast { expr, type_ref } => {
                 let _inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
@@ -614,8 +606,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         self.unify(&expected_receiver_ty, &actual_receiver_ty);
 
         self.check_call_arguments(args, &param_tys);
-        let ret_ty = self.normalize_associated_types_in(ret_ty);
-        ret_ty
+        self.normalize_associated_types_in(ret_ty)
     }
 
     fn check_call_arguments(&mut self, args: &[ExprId], param_tys: &[Ty]) {
@@ -700,10 +691,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                             // construct a TraitDef
                             let substs =
                                 a_ty.parameters.prefix(generics(self.db, trait_.into()).len());
-                            self.obligations.push(Obligation::Trait(TraitRef {
-                                trait_: trait_.into(),
-                                substs,
-                            }));
+                            self.obligations.push(Obligation::Trait(TraitRef { trait_, substs }));
                         }
                     }
                     CallableDef::StructId(_) | CallableDef::EnumVariantId(_) => {}
diff --git a/crates/ra_hir_ty/src/infer/pat.rs b/crates/ra_hir_ty/src/infer/pat.rs
index a5dfdf6c4..a495ecbfe 100644
--- a/crates/ra_hir_ty/src/infer/pat.rs
+++ b/crates/ra_hir_ty/src/infer/pat.rs
@@ -28,7 +28,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
         let substs = ty.substs().unwrap_or_else(Substs::empty);
 
-        let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default();
+        let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
 
         for (i, &subpat) in subpats.iter().enumerate() {
             let expected_ty = var_data
@@ -60,7 +60,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
         let substs = ty.substs().unwrap_or_else(Substs::empty);
 
-        let field_tys = def.map(|it| self.db.field_types(it.into())).unwrap_or_default();
+        let field_tys = def.map(|it| self.db.field_types(it)).unwrap_or_default();
         for subpat in subpats {
             let matching_field = var_data.as_ref().and_then(|it| it.field(&subpat.name));
             let expected_ty =
diff --git a/crates/ra_hir_ty/src/infer/path.rs b/crates/ra_hir_ty/src/infer/path.rs
index 686ce7a21..471d60342 100644
--- a/crates/ra_hir_ty/src/infer/path.rs
+++ b/crates/ra_hir_ty/src/infer/path.rs
@@ -104,8 +104,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 let segment =
                     remaining_segments.last().expect("there should be at least one segment here");
                 let ctx = crate::lower::TyLoweringContext::new(self.db, &self.resolver);
-                let trait_ref =
-                    TraitRef::from_resolved_path(&ctx, trait_.into(), resolved_segment, None);
+                let trait_ref = TraitRef::from_resolved_path(&ctx, trait_, resolved_segment, None);
                 self.resolve_trait_assoc_item(trait_ref, segment, id)
             }
             (def, _) => {
@@ -144,30 +143,32 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         id: ExprOrPatId,
     ) -> Option<(ValueNs, Option<Substs>)> {
         let trait_ = trait_ref.trait_;
-        let item = self
-            .db
-            .trait_data(trait_)
-            .items
-            .iter()
-            .map(|(_name, id)| (*id).into())
-            .find_map(|item| match item {
-                AssocItemId::FunctionId(func) => {
-                    if segment.name == &self.db.function_data(func).name {
-                        Some(AssocItemId::FunctionId(func))
-                    } else {
-                        None
+        let item =
+            self.db.trait_data(trait_).items.iter().map(|(_name, id)| (*id)).find_map(|item| {
+                match item {
+                    AssocItemId::FunctionId(func) => {
+                        if segment.name == &self.db.function_data(func).name {
+                            Some(AssocItemId::FunctionId(func))
+                        } else {
+                            None
+                        }
                     }
-                }
 
-                AssocItemId::ConstId(konst) => {
-                    if self.db.const_data(konst).name.as_ref().map_or(false, |n| n == segment.name)
-                    {
-                        Some(AssocItemId::ConstId(konst))
-                    } else {
-                        None
+                    AssocItemId::ConstId(konst) => {
+                        if self
+                            .db
+                            .const_data(konst)
+                            .name
+                            .as_ref()
+                            .map_or(false, |n| n == segment.name)
+                        {
+                            Some(AssocItemId::ConstId(konst))
+                        } else {
+                            None
+                        }
                     }
+                    AssocItemId::TypeAliasId(_) => None,
                 }
-                AssocItemId::TypeAliasId(_) => None,
             })?;
         let def = match item {
             AssocItemId::FunctionId(f) => ValueNs::FunctionId(f),
@@ -233,7 +234,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     AssocContainerId::ContainerId(_) => None,
                 };
 
-                self.write_assoc_resolution(id, item.into());
+                self.write_assoc_resolution(id, item);
                 Some((def, substs))
             },
         )
diff --git a/crates/ra_hir_ty/src/infer/unify.rs b/crates/ra_hir_ty/src/infer/unify.rs
index 1dc842f40..9c7996572 100644
--- a/crates/ra_hir_ty/src/infer/unify.rs
+++ b/crates/ra_hir_ty/src/infer/unify.rs
@@ -140,13 +140,12 @@ where
 impl<T> Canonicalized<T> {
     pub fn decanonicalize_ty(&self, mut ty: Ty) -> Ty {
         ty.walk_mut_binders(
-            &mut |ty, binders| match ty {
-                &mut Ty::Bound(idx) => {
+            &mut |ty, binders| {
+                if let &mut Ty::Bound(idx) = ty {
                     if idx as usize >= binders && (idx as usize - binders) < self.free_vars.len() {
                         *ty = Ty::Infer(self.free_vars[idx as usize - binders]);
                     }
                 }
-                _ => {}
             },
             0,
         );
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 571579cc4..13c5e6c6b 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -167,7 +167,7 @@ impl TypeCtor {
             | TypeCtor::Closure { .. } // 1 param representing the signature of the closure
             => 1,
             TypeCtor::Adt(adt) => {
-                let generic_params = generics(db, AdtId::from(adt).into());
+                let generic_params = generics(db, adt.into());
                 generic_params.len()
             }
             TypeCtor::FnDef(callable) => {
@@ -247,7 +247,7 @@ pub struct ProjectionTy {
 
 impl ProjectionTy {
     pub fn trait_ref(&self, db: &impl HirDatabase) -> TraitRef {
-        TraitRef { trait_: self.trait_(db).into(), substs: self.parameters.clone() }
+        TraitRef { trait_: self.trait_(db), substs: self.parameters.clone() }
     }
 
     fn trait_(&self, db: &impl HirDatabase) -> TraitId {
@@ -763,8 +763,8 @@ pub trait TypeWalk {
         Self: Sized,
     {
         self.walk_mut_binders(
-            &mut |ty, binders| match ty {
-                &mut Ty::Bound(idx) => {
+            &mut |ty, binders| {
+                if let &mut Ty::Bound(idx) = ty {
                     if idx as usize >= binders && (idx as usize - binders) < substs.len() {
                         *ty = substs.0[idx as usize - binders].clone();
                     } else if idx as usize >= binders + substs.len() {
@@ -772,7 +772,6 @@ pub trait TypeWalk {
                         *ty = Ty::Bound(idx - substs.len() as u32);
                     }
                 }
-                _ => {}
             },
             0,
         );
diff --git a/crates/ra_hir_ty/src/lower.rs b/crates/ra_hir_ty/src/lower.rs
index c2a3703fa..52da34574 100644
--- a/crates/ra_hir_ty/src/lower.rs
+++ b/crates/ra_hir_ty/src/lower.rs
@@ -361,10 +361,8 @@ impl Ty {
         for t in traits {
             if let Some(associated_ty) = ctx.db.trait_data(t).associated_type_by_name(&segment.name)
             {
-                let substs = Substs::build_for_def(ctx.db, t)
-                    .push(self_ty.clone())
-                    .fill_with_unknown()
-                    .build();
+                let substs =
+                    Substs::build_for_def(ctx.db, t).push(self_ty).fill_with_unknown().build();
                 // FIXME handle type parameters on the segment
                 return Ty::Projection(ProjectionTy { associated_ty, parameters: substs });
             }
@@ -428,7 +426,7 @@ pub(super) fn substs_from_path_segment(
     _add_self_param: bool,
 ) -> Substs {
     let mut substs = Vec::new();
-    let def_generics = def_generic.map(|def| generics(ctx.db, def.into()));
+    let def_generics = def_generic.map(|def| generics(ctx.db, def));
 
     let (parent_params, self_params, type_params, impl_trait_params) =
         def_generics.map_or((0, 0, 0, 0), |g| g.provenance_split());
@@ -459,7 +457,7 @@ pub(super) fn substs_from_path_segment(
 
     // handle defaults
     if let Some(def_generic) = def_generic {
-        let default_substs = ctx.db.generic_defaults(def_generic.into());
+        let default_substs = ctx.db.generic_defaults(def_generic);
         assert_eq!(substs.len(), default_substs.len());
 
         for (i, default_ty) in default_substs.iter().enumerate() {
@@ -483,7 +481,7 @@ impl TraitRef {
             _ => return None,
         };
         let segment = path.segments().last().expect("path should have at least one segment");
-        Some(TraitRef::from_resolved_path(ctx, resolved.into(), segment, explicit_self_ty))
+        Some(TraitRef::from_resolved_path(ctx, resolved, segment, explicit_self_ty))
     }
 
     pub(crate) fn from_resolved_path(
@@ -728,7 +726,7 @@ pub(crate) fn generic_predicates_query(
 pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDefId) -> Substs {
     let resolver = def.resolver(db);
     let ctx = TyLoweringContext::new(db, &resolver);
-    let generic_params = generics(db, def.into());
+    let generic_params = generics(db, def);
 
     let defaults = generic_params
         .iter()
@@ -792,7 +790,7 @@ fn type_for_builtin(def: BuiltinType) -> Ty {
 }
 
 fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> PolyFnSig {
-    let struct_data = db.struct_data(def.into());
+    let struct_data = db.struct_data(def);
     let fields = struct_data.variant_data.fields();
     let resolver = def.resolver(db);
     let ctx =
@@ -805,7 +803,7 @@ fn fn_sig_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> PolyFn
 
 /// Build the type of a tuple struct constructor.
 fn type_for_struct_constructor(db: &impl HirDatabase, def: StructId) -> Binders<Ty> {
-    let struct_data = db.struct_data(def.into());
+    let struct_data = db.struct_data(def);
     if let StructKind::Unit = struct_data.variant_data.kind() {
         return type_for_adt(db, def.into());
     }
@@ -836,7 +834,7 @@ fn type_for_enum_variant_constructor(db: &impl HirDatabase, def: EnumVariantId)
     }
     let generics = generics(db, def.parent.into());
     let substs = Substs::bound_vars(&generics);
-    Binders::new(substs.len(), Ty::apply(TypeCtor::FnDef(EnumVariantId::from(def).into()), substs))
+    Binders::new(substs.len(), Ty::apply(TypeCtor::FnDef(def.into()), substs))
 }
 
 fn type_for_adt(db: &impl HirDatabase, adt: AdtId) -> Binders<Ty> {
@@ -964,6 +962,6 @@ pub(crate) fn impl_trait_query(
     let target_trait = impl_data.target_trait.as_ref()?;
     Some(Binders::new(
         self_ty.num_binders,
-        TraitRef::from_hir(&ctx, target_trait, Some(self_ty.value.clone()))?,
+        TraitRef::from_hir(&ctx, target_trait, Some(self_ty.value))?,
     ))
 }
diff --git a/crates/ra_hir_ty/src/method_resolution.rs b/crates/ra_hir_ty/src/method_resolution.rs
index 4f8c52433..964acdb09 100644
--- a/crates/ra_hir_ty/src/method_resolution.rs
+++ b/crates/ra_hir_ty/src/method_resolution.rs
@@ -214,7 +214,7 @@ pub fn iterate_method_candidates<T>(
             // the methods by autoderef order of *receiver types*, not *self
             // types*.
 
-            let deref_chain: Vec<_> = autoderef::autoderef(db, Some(krate), ty.clone()).collect();
+            let deref_chain: Vec<_> = autoderef::autoderef(db, Some(krate), ty).collect();
             for i in 0..deref_chain.len() {
                 if let Some(result) = iterate_method_candidates_with_autoref(
                     &deref_chain[i..],
@@ -290,7 +290,7 @@ fn iterate_method_candidates_with_autoref<T>(
         &ref_muted,
         deref_chain,
         db,
-        env.clone(),
+        env,
         krate,
         &traits_in_scope,
         name,
@@ -391,17 +391,17 @@ fn iterate_trait_method_candidates<T>(
         // iteration
         let mut known_implemented = false;
         for (_name, item) in data.items.iter() {
-            if !is_valid_candidate(db, name, receiver_ty, (*item).into(), self_ty) {
+            if !is_valid_candidate(db, name, receiver_ty, *item, self_ty) {
                 continue;
             }
             if !known_implemented {
                 let goal = generic_implements_goal(db, env.clone(), t, self_ty.clone());
-                if db.trait_solve(krate.into(), goal).is_none() {
+                if db.trait_solve(krate, goal).is_none() {
                     continue 'traits;
                 }
             }
             known_implemented = true;
-            if let Some(result) = callback(&self_ty.value, (*item).into()) {
+            if let Some(result) = callback(&self_ty.value, *item) {
                 return Some(result);
             }
         }
@@ -521,7 +521,7 @@ pub fn implements_trait(
         return true;
     }
     let goal = generic_implements_goal(db, env, trait_, ty.clone());
-    let solution = db.trait_solve(krate.into(), goal);
+    let solution = db.trait_solve(krate, goal);
 
     solution.is_some()
 }
diff --git a/crates/ra_hir_ty/src/op.rs b/crates/ra_hir_ty/src/op.rs
index ae253ca04..54e2bd05a 100644
--- a/crates/ra_hir_ty/src/op.rs
+++ b/crates/ra_hir_ty/src/op.rs
@@ -30,20 +30,18 @@ pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
 pub(super) fn binary_op_rhs_expectation(op: BinaryOp, lhs_ty: Ty) -> Ty {
     match op {
         BinaryOp::LogicOp(..) => Ty::simple(TypeCtor::Bool),
-        BinaryOp::Assignment { op: None } | BinaryOp::CmpOp(CmpOp::Eq { negated: _ }) => {
-            match lhs_ty {
-                Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
-                    TypeCtor::Int(..)
-                    | TypeCtor::Float(..)
-                    | TypeCtor::Str
-                    | TypeCtor::Char
-                    | TypeCtor::Bool => lhs_ty,
-                    _ => Ty::Unknown,
-                },
-                Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
+        BinaryOp::Assignment { op: None } | BinaryOp::CmpOp(CmpOp::Eq { .. }) => match lhs_ty {
+            Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
+                TypeCtor::Int(..)
+                | TypeCtor::Float(..)
+                | TypeCtor::Str
+                | TypeCtor::Char
+                | TypeCtor::Bool => lhs_ty,
                 _ => Ty::Unknown,
-            }
-        }
+            },
+            Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
+            _ => Ty::Unknown,
+        },
         BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => Ty::Unknown,
         BinaryOp::CmpOp(CmpOp::Ord { .. })
         | BinaryOp::Assignment { op: Some(_) }
diff --git a/crates/ra_hir_ty/src/test_db.rs b/crates/ra_hir_ty/src/test_db.rs
index 1a31b587b..c794f7b84 100644
--- a/crates/ra_hir_ty/src/test_db.rs
+++ b/crates/ra_hir_ty/src/test_db.rs
@@ -86,15 +86,14 @@ impl TestDB {
     pub fn diagnostics(&self) -> String {
         let mut buf = String::new();
         let crate_graph = self.crate_graph();
-        for krate in crate_graph.iter().next() {
+        for krate in crate_graph.iter() {
             let crate_def_map = self.crate_def_map(krate);
 
             let mut fns = Vec::new();
             for (module_id, _) in crate_def_map.modules.iter() {
                 for decl in crate_def_map[module_id].scope.declarations() {
-                    match decl {
-                        ModuleDefId::FunctionId(f) => fns.push(f),
-                        _ => (),
+                    if let ModuleDefId::FunctionId(f) = decl {
+                        fns.push(f)
                     }
                 }
 
diff --git a/crates/ra_hir_ty/src/tests.rs b/crates/ra_hir_ty/src/tests.rs
index d1f10e675..240cc03a2 100644
--- a/crates/ra_hir_ty/src/tests.rs
+++ b/crates/ra_hir_ty/src/tests.rs
@@ -101,9 +101,9 @@ fn infer_with_mismatches(content: &str, include_mismatches: bool) -> String {
                 (src_ptr.value.range(), node.text().to_string().replace("\n", " "))
             };
             let macro_prefix = if src_ptr.file_id != file_id.into() { "!" } else { "" };
-            write!(
+            writeln!(
                 acc,
-                "{}{} '{}': {}\n",
+                "{}{} '{}': {}",
                 macro_prefix,
                 range,
                 ellipsize(text, 15),
@@ -118,9 +118,9 @@ fn infer_with_mismatches(content: &str, include_mismatches: bool) -> String {
             for (src_ptr, mismatch) in &mismatches {
                 let range = src_ptr.value.range();
                 let macro_prefix = if src_ptr.file_id != file_id.into() { "!" } else { "" };
-                write!(
+                writeln!(
                     acc,
-                    "{}{}: expected {}, got {}\n",
+                    "{}{}: expected {}, got {}",
                     macro_prefix,
                     range,
                     mismatch.expected.display(&db),
diff --git a/crates/ra_hir_ty/src/traits.rs b/crates/ra_hir_ty/src/traits.rs
index ff8e75b48..e83449957 100644
--- a/crates/ra_hir_ty/src/traits.rs
+++ b/crates/ra_hir_ty/src/traits.rs
@@ -248,12 +248,9 @@ fn solution_from_chalk(
         let value = subst
             .value
             .into_iter()
-            .map(|p| {
-                let ty = match p.ty() {
-                    Some(ty) => from_chalk(db, ty.clone()),
-                    None => unimplemented!(),
-                };
-                ty
+            .map(|p| match p.ty() {
+                Some(ty) => from_chalk(db, ty.clone()),
+                None => unimplemented!(),
             })
             .collect();
         let result = Canonical { value, num_vars: subst.binders.len() };
diff --git a/crates/ra_hir_ty/src/traits/builtin.rs b/crates/ra_hir_ty/src/traits/builtin.rs
index dd41176f0..a537420a5 100644
--- a/crates/ra_hir_ty/src/traits/builtin.rs
+++ b/crates/ra_hir_ty/src/traits/builtin.rs
@@ -98,7 +98,7 @@ fn closure_fn_trait_impl_datum(
         // the existence of the Fn trait has been checked before
         .expect("fn trait for closure impl missing");
 
-    let num_args: u16 = match &db.body(data.def.into())[data.expr] {
+    let num_args: u16 = match &db.body(data.def)[data.expr] {
         Expr::Lambda { args, .. } => args.len() as u16,
         _ => {
             log::warn!("closure for closure type {:?} not found", data);
@@ -118,11 +118,11 @@ fn closure_fn_trait_impl_datum(
     let self_ty = Ty::apply_one(TypeCtor::Closure { def: data.def, expr: data.expr }, sig_ty);
 
     let trait_ref = TraitRef {
-        trait_: trait_.into(),
+        trait_,
         substs: Substs::build_for_def(db, trait_).push(self_ty).push(arg_ty).build(),
     };
 
-    let output_ty_id = AssocTyValue::ClosureFnTraitImplOutput(data.clone());
+    let output_ty_id = AssocTyValue::ClosureFnTraitImplOutput(data);
 
     BuiltinImplData {
         num_vars: num_args as usize + 1,
@@ -137,9 +137,9 @@ fn closure_fn_trait_output_assoc_ty_value(
     krate: CrateId,
     data: super::ClosureFnTraitImplData,
 ) -> BuiltinImplAssocTyValueData {
-    let impl_ = Impl::ClosureFnTraitImpl(data.clone());
+    let impl_ = Impl::ClosureFnTraitImpl(data);
 
-    let num_args: u16 = match &db.body(data.def.into())[data.expr] {
+    let num_args: u16 = match &db.body(data.def)[data.expr] {
         Expr::Lambda { args, .. } => args.len() as u16,
         _ => {
             log::warn!("closure for closure type {:?} not found", data);
diff --git a/crates/ra_hir_ty/src/traits/chalk.rs b/crates/ra_hir_ty/src/traits/chalk.rs
index 882160fa8..1bdf13e48 100644
--- a/crates/ra_hir_ty/src/traits/chalk.rs
+++ b/crates/ra_hir_ty/src/traits/chalk.rs
@@ -409,8 +409,7 @@ where
     fn to_chalk(self, db: &impl HirDatabase) -> chalk_ir::Canonical<T::Chalk> {
         let parameter = chalk_ir::ParameterKind::Ty(chalk_ir::UniverseIndex::ROOT);
         let value = self.value.to_chalk(db);
-        let canonical = chalk_ir::Canonical { value, binders: vec![parameter; self.num_vars] };
-        canonical
+        chalk_ir::Canonical { value, binders: vec![parameter; self.num_vars] }
     }
 
     fn from_chalk(db: &impl HirDatabase, canonical: chalk_ir::Canonical<T::Chalk>) -> Canonical<T> {
@@ -565,10 +564,10 @@ where
         // and will panic if the trait can't be resolved.
         let mut result: Vec<_> = self
             .db
-            .impls_for_trait(self.krate, trait_.into())
+            .impls_for_trait(self.krate, trait_)
             .iter()
             .copied()
-            .map(|it| Impl::ImplBlock(it.into()))
+            .map(Impl::ImplBlock)
             .map(|impl_| impl_.to_chalk(self.db))
             .collect();
 
@@ -586,7 +585,7 @@ where
         false // FIXME
     }
     fn associated_ty_value(&self, id: AssociatedTyValueId) -> Arc<AssociatedTyValue> {
-        self.db.associated_ty_value(self.krate.into(), id)
+        self.db.associated_ty_value(self.krate, id)
     }
     fn custom_clauses(&self) -> Vec<chalk_ir::ProgramClause<TypeFamily>> {
         vec![]
@@ -674,7 +673,7 @@ pub(crate) fn struct_datum_query(
     let where_clauses = type_ctor
         .as_generic_def()
         .map(|generic_def| {
-            let generic_params = generics(db, generic_def.into());
+            let generic_params = generics(db, generic_def);
             let bound_vars = Substs::bound_vars(&generic_params);
             convert_where_clauses(db, generic_def, &bound_vars)
         })
@@ -805,7 +804,7 @@ fn type_alias_associated_ty_value(
     let ty = db.ty(type_alias.into());
     let value_bound = chalk_rust_ir::AssociatedTyValueBound { ty: ty.value.to_chalk(db) };
     let value = chalk_rust_ir::AssociatedTyValue {
-        impl_id: Impl::ImplBlock(impl_id.into()).to_chalk(db),
+        impl_id: Impl::ImplBlock(impl_id).to_chalk(db),
         associated_ty_id: assoc_ty.to_chalk(db),
         value: make_binders(value_bound, ty.num_binders),
     };