Merge #1374

1374: Implement `cargo lint` and fix some clippy errors r=alanhdu a=alanhdu

This creates a `cargo lint` command that runs clippy with certain lints disabled. I've also gone ahead and fixed some of the lint errors, although there are many more still to go.

cc #848 

Co-authored-by: Alan Du <[email protected]>

3 files changed, 38 insertions, 52 deletions

diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index e8ae33ead..905fe9f0e 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -462,7 +462,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         let mut resolved =
             if remaining_index.is_none() { def.take_values()? } else { def.take_types()? };
 
-        let remaining_index = remaining_index.unwrap_or(path.segments.len());
+        let remaining_index = remaining_index.unwrap_or_else(|| path.segments.len());
         let mut actual_def_ty: Option<Ty> = None;
 
         let krate = resolver.krate()?;
@@ -539,7 +539,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                 }
             })?;
 
-            resolved = Resolution::Def(item.into());
+            resolved = Resolution::Def(item);
         }
 
         match resolved {
@@ -762,7 +762,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     _ => &Ty::Unknown,
                 };
                 let subty = self.infer_pat(*pat, expectation, default_bm);
-                Ty::apply_one(TypeCtor::Ref(*mutability), subty.into())
+                Ty::apply_one(TypeCtor::Ref(*mutability), subty)
             }
             Pat::TupleStruct { path: ref p, args: ref subpats } => {
                 self.infer_tuple_struct_pat(p.as_ref(), subpats, expected, default_bm)
@@ -790,7 +790,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
 
                 let bound_ty = match mode {
                     BindingMode::Ref(mutability) => {
-                        Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone().into())
+                        Ty::apply_one(TypeCtor::Ref(mutability), inner_ty.clone())
                     }
                     BindingMode::Move => inner_ty.clone(),
                 };
@@ -848,28 +848,23 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
     }
 
     fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
-        match callable_ty {
-            Ty::Apply(a_ty) => match a_ty.ctor {
-                TypeCtor::FnDef(def) => {
-                    // add obligation for trait implementation, if this is a trait method
-                    // FIXME also register obligations from where clauses from the trait or impl and method
-                    match def {
-                        CallableDef::Function(f) => {
-                            if let Some(trait_) = f.parent_trait(self.db) {
-                                // construct a TraitDef
-                                let substs = a_ty.parameters.prefix(
-                                    trait_.generic_params(self.db).count_params_including_parent(),
-                                );
-                                self.obligations
-                                    .push(Obligation::Trait(TraitRef { trait_, substs }));
-                            }
+        if let Ty::Apply(a_ty) = callable_ty {
+            if let TypeCtor::FnDef(def) = a_ty.ctor {
+                // add obligation for trait implementation, if this is a trait method
+                // FIXME also register obligations from where clauses from the trait or impl and method
+                match def {
+                    CallableDef::Function(f) => {
+                        if let Some(trait_) = f.parent_trait(self.db) {
+                            // construct a TraitDef
+                            let substs = a_ty.parameters.prefix(
+                                trait_.generic_params(self.db).count_params_including_parent(),
+                            );
+                            self.obligations.push(Obligation::Trait(TraitRef { trait_, substs }));
                         }
-                        CallableDef::Struct(_) | CallableDef::EnumVariant(_) => {}
                     }
+                    CallableDef::Struct(_) | CallableDef::EnumVariant(_) => {}
                 }
-                _ => {}
-            },
-            _ => {}
+            }
         }
     }
 
@@ -1049,7 +1044,7 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
             Expr::StructLit { path, fields, spread } => {
                 let (ty, def_id) = self.resolve_variant(path.as_ref());
                 let substs = ty.substs().unwrap_or_else(Substs::empty);
-                for (field_idx, field) in fields.into_iter().enumerate() {
+                for (field_idx, field) in fields.iter().enumerate() {
                     let field_ty = def_id
                         .and_then(|it| match it.field(self.db, &field.name) {
                             Some(field) => Some(field),
diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index 34817a5ec..646e58aa9 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -192,23 +192,20 @@ fn iterate_trait_method_candidates<T>(
         // iteration
         let mut known_implemented = false;
         for item in data.items() {
-            match item {
-                &TraitItem::Function(m) => {
-                    let sig = m.signature(db);
-                    if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() {
-                        if !known_implemented {
-                            let trait_ref = canonical_trait_ref(db, t, ty.clone());
-                            if db.implements(krate, trait_ref).is_none() {
-                                continue 'traits;
-                            }
-                        }
-                        known_implemented = true;
-                        if let Some(result) = callback(&ty.value, m) {
-                            return Some(result);
+            if let TraitItem::Function(m) = *item {
+                let sig = m.signature(db);
+                if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() {
+                    if !known_implemented {
+                        let trait_ref = canonical_trait_ref(db, t, ty.clone());
+                        if db.implements(krate, trait_ref).is_none() {
+                            continue 'traits;
                         }
                     }
+                    known_implemented = true;
+                    if let Some(result) = callback(&ty.value, m) {
+                        return Some(result);
+                    }
                 }
-                _ => {}
             }
         }
     }
@@ -230,16 +227,13 @@ fn iterate_inherent_methods<T>(
 
     for impl_block in impls.lookup_impl_blocks(&ty.value) {
         for item in impl_block.items(db) {
-            match item {
-                ImplItem::Method(f) => {
-                    let sig = f.signature(db);
-                    if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() {
-                        if let Some(result) = callback(&ty.value, f) {
-                            return Some(result);
-                        }
+            if let ImplItem::Method(f) = item {
+                let sig = f.signature(db);
+                if name.map_or(true, |name| sig.name() == name) && sig.has_self_param() {
+                    if let Some(result) = callback(&ty.value, f) {
+                        return Some(result);
                     }
                 }
-                _ => {}
             }
         }
     }
diff --git a/crates/ra_hir/src/ty/traits/chalk.rs b/crates/ra_hir/src/ty/traits/chalk.rs
index 78440b258..1e4806db0 100644
--- a/crates/ra_hir/src/ty/traits/chalk.rs
+++ b/crates/ra_hir/src/ty/traits/chalk.rs
@@ -211,13 +211,10 @@ fn convert_where_clauses(
             // anyway), otherwise Chalk can easily get into slow situations
             return vec![pred.clone().subst(substs).to_chalk(db)];
         }
-        match pred {
-            GenericPredicate::Implemented(trait_ref) => {
-                if blacklisted_trait(db, trait_ref.trait_) {
-                    continue;
-                }
+        if let GenericPredicate::Implemented(trait_ref) = pred {
+            if blacklisted_trait(db, trait_ref.trait_) {
+                continue;
             }
-            _ => {}
         }
         result.push(pred.clone().subst(substs).to_chalk(db));
     }