Rollup of 12 pull requests

src/liballoc/collections/linked_list.rs

@@ -959,7 +959,7 @@ impl<T> LinkedList<T> {
         let it = self.head;
         let old_len = self.len;
 
-        DrainFilter { list: self, it: it, pred: filter, idx: 0, old_len: old_len }
+        DrainFilter { list: self, it, pred: filter, idx: 0, old_len }
     }
 }
 

src/liballoc/vec.rs

@@ -1659,7 +1659,7 @@ struct SetLenOnDrop<'a> {
 impl<'a> SetLenOnDrop<'a> {
     #[inline]
     fn new(len: &'a mut usize) -> Self {
-        SetLenOnDrop { local_len: *len, len: len }
+        SetLenOnDrop { local_len: *len, len }
     }
 
     #[inline]

src/libcore/slice/mod.rs

@@ -103,7 +103,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn first(&self) -> Option<&T> {
-        self.get(0)
+        if let [first, ..] = self { Some(first) } else { None }
     }
 
     /// Returns a mutable pointer to the first element of the slice, or `None` if it is empty.
@@ -121,7 +121,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn first_mut(&mut self) -> Option<&mut T> {
-        self.get_mut(0)
+        if let [first, ..] = self { Some(first) } else { None }
     }
 
     /// Returns the first and all the rest of the elements of the slice, or `None` if it is empty.
@@ -139,7 +139,7 @@ impl<T> [T] {
     #[stable(feature = "slice_splits", since = "1.5.0")]
     #[inline]
     pub fn split_first(&self) -> Option<(&T, &[T])> {
-        if self.is_empty() { None } else { Some((&self[0], &self[1..])) }
+        if let [first, tail @ ..] = self { Some((first, tail)) } else { None }
     }
 
     /// Returns the first and all the rest of the elements of the slice, or `None` if it is empty.
@@ -159,12 +159,7 @@ impl<T> [T] {
     #[stable(feature = "slice_splits", since = "1.5.0")]
     #[inline]
     pub fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])> {
-        if self.is_empty() {
-            None
-        } else {
-            let split = self.split_at_mut(1);
-            Some((&mut split.0[0], split.1))
-        }
+        if let [first, tail @ ..] = self { Some((first, tail)) } else { None }
     }
 
     /// Returns the last and all the rest of the elements of the slice, or `None` if it is empty.
@@ -182,8 +177,7 @@ impl<T> [T] {
     #[stable(feature = "slice_splits", since = "1.5.0")]
     #[inline]
     pub fn split_last(&self) -> Option<(&T, &[T])> {
-        let len = self.len();
-        if len == 0 { None } else { Some((&self[len - 1], &self[..(len - 1)])) }
+        if let [init @ .., last] = self { Some((last, init)) } else { None }
     }
 
     /// Returns the last and all the rest of the elements of the slice, or `None` if it is empty.
@@ -203,13 +197,7 @@ impl<T> [T] {
     #[stable(feature = "slice_splits", since = "1.5.0")]
     #[inline]
     pub fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])> {
-        let len = self.len();
-        if len == 0 {
-            None
-        } else {
-            let split = self.split_at_mut(len - 1);
-            Some((&mut split.1[0], split.0))
-        }
+        if let [init @ .., last] = self { Some((last, init)) } else { None }
     }
 
     /// Returns the last element of the slice, or `None` if it is empty.
@@ -226,8 +214,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn last(&self) -> Option<&T> {
-        let last_idx = self.len().checked_sub(1)?;
-        self.get(last_idx)
+        if let [.., last] = self { Some(last) } else { None }
     }
 
     /// Returns a mutable pointer to the last item in the slice.
@@ -245,8 +232,7 @@ impl<T> [T] {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn last_mut(&mut self) -> Option<&mut T> {
-        let last_idx = self.len().checked_sub(1)?;
-        self.get_mut(last_idx)
+        if let [.., last] = self { Some(last) } else { None }
     }
 
     /// Returns a reference to an element or subslice depending on the type of

src/libproc_macro/diagnostic.rs

@@ -55,13 +55,15 @@ pub struct Diagnostic {
 }
 
 macro_rules! diagnostic_child_methods {
-    ($spanned:ident, $regular:ident, $level:expr) => (
+    ($spanned:ident, $regular:ident, $level:expr) => {
         /// Adds a new child diagnostic message to `self` with the level
         /// identified by this method's name with the given `spans` and
         /// `message`.
         #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
         pub fn $spanned<S, T>(mut self, spans: S, message: T) -> Diagnostic
-            where S: MultiSpan, T: Into<String>
+        where
+            S: MultiSpan,
+            T: Into<String>,
         {
             self.children.push(Diagnostic::spanned(spans, $level, message));
             self
@@ -74,7 +76,7 @@ macro_rules! diagnostic_child_methods {
             self.children.push(Diagnostic::new($level, message));
             self
         }
-    )
+    };
 }
 
 /// Iterator over the children diagnostics of a `Diagnostic`.
@@ -96,7 +98,7 @@ impl Diagnostic {
     /// Creates a new diagnostic with the given `level` and `message`.
     #[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
     pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
-        Diagnostic { level: level, message: message.into(), spans: vec![], children: vec![] }
+        Diagnostic { level, message: message.into(), spans: vec![], children: vec![] }
     }
 
     /// Creates a new diagnostic with the given `level` and `message` pointing to
@@ -107,12 +109,7 @@ impl Diagnostic {
         S: MultiSpan,
         T: Into<String>,
     {
-        Diagnostic {
-            level: level,
-            message: message.into(),
-            spans: spans.into_spans(),
-            children: vec![],
-        }
+        Diagnostic { level, message: message.into(), spans: spans.into_spans(), children: vec![] }
     }
 
     diagnostic_child_methods!(span_error, error, Level::Error);

src/librustc/hir/map/blocks.rs

@@ -60,7 +60,7 @@ impl MaybeFnLike for hir::ImplItem<'_> {
 impl MaybeFnLike for hir::TraitItem<'_> {
     fn is_fn_like(&self) -> bool {
         match self.kind {
-            hir::TraitItemKind::Method(_, hir::TraitMethod::Provided(_)) => true,
+            hir::TraitItemKind::Fn(_, hir::TraitMethod::Provided(_)) => true,
             _ => false,
         }
     }
@@ -239,7 +239,7 @@ impl<'a> FnLikeNode<'a> {
                 _ => bug!("item FnLikeNode that is not fn-like"),
             },
             Node::TraitItem(ti) => match ti.kind {
-                hir::TraitItemKind::Method(ref sig, hir::TraitMethod::Provided(body)) => {
+                hir::TraitItemKind::Fn(ref sig, hir::TraitMethod::Provided(body)) => {
                     method(ti.hir_id, ti.ident, sig, None, body, ti.span, &ti.attrs)
                 }
                 _ => bug!("trait method FnLikeNode that is not fn-like"),

src/librustc/hir/map/definitions.rs

@@ -192,7 +192,7 @@ impl DefPath {
             }
         }
         data.reverse();
-        DefPath { data: data, krate: krate }
+        DefPath { data, krate }
     }
 
     /// Returns a string representation of the `DefPath` without

src/librustc/hir/map/mod.rs

@@ -51,7 +51,7 @@ impl<'hir> Entry<'hir> {
             },
 
             Node::TraitItem(ref item) => match item.kind {
-                TraitItemKind::Method(ref sig, _) => Some(&sig.decl),
+                TraitItemKind::Fn(ref sig, _) => Some(&sig.decl),
                 _ => None,
             },
 
@@ -77,7 +77,7 @@ impl<'hir> Entry<'hir> {
             },
 
             Node::TraitItem(item) => match &item.kind {
-                TraitItemKind::Method(sig, _) => Some(sig),
+                TraitItemKind::Fn(sig, _) => Some(sig),
                 _ => None,
             },
 
@@ -101,7 +101,7 @@ impl<'hir> Entry<'hir> {
 
             Node::TraitItem(item) => match item.kind {
                 TraitItemKind::Const(_, Some(body))
-                | TraitItemKind::Method(_, TraitMethod::Provided(body)) => Some(body),
+                | TraitItemKind::Fn(_, TraitMethod::Provided(body)) => Some(body),
                 _ => None,
             },
 
@@ -326,12 +326,12 @@ impl<'hir> Map<'hir> {
             },
             Node::TraitItem(item) => match item.kind {
                 TraitItemKind::Const(..) => DefKind::AssocConst,
-                TraitItemKind::Method(..) => DefKind::Method,
+                TraitItemKind::Fn(..) => DefKind::AssocFn,
                 TraitItemKind::Type(..) => DefKind::AssocTy,
             },
             Node::ImplItem(item) => match item.kind {
                 ImplItemKind::Const(..) => DefKind::AssocConst,
-                ImplItemKind::Method(..) => DefKind::Method,
+                ImplItemKind::Method(..) => DefKind::AssocFn,
                 ImplItemKind::TyAlias(..) => DefKind::AssocTy,
                 ImplItemKind::OpaqueTy(..) => DefKind::AssocOpaqueTy,
             },
@@ -472,7 +472,7 @@ impl<'hir> Map<'hir> {
             | Node::AnonConst(_) => BodyOwnerKind::Const,
             Node::Ctor(..)
             | Node::Item(&Item { kind: ItemKind::Fn(..), .. })
-            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Method(..), .. })
+            | Node::TraitItem(&TraitItem { kind: TraitItemKind::Fn(..), .. })
             | Node::ImplItem(&ImplItem { kind: ImplItemKind::Method(..), .. }) => BodyOwnerKind::Fn,
             Node::Item(&Item { kind: ItemKind::Static(_, m, _), .. }) => BodyOwnerKind::Static(m),
             Node::Expr(&Expr { kind: ExprKind::Closure(..), .. }) => BodyOwnerKind::Closure,
@@ -800,7 +800,7 @@ impl<'hir> Map<'hir> {
                     _ => false,
                 },
                 Node::TraitItem(ti) => match ti.kind {
-                    TraitItemKind::Method(..) => true,
+                    TraitItemKind::Fn(..) => true,
                     _ => false,
                 },
                 Node::ImplItem(ii) => match ii.kind {
@@ -1311,7 +1311,7 @@ fn hir_id_to_string(map: &Map<'_>, id: HirId, include_id: bool) -> String {
         Some(Node::TraitItem(ti)) => {
             let kind = match ti.kind {
                 TraitItemKind::Const(..) => "assoc constant",
-                TraitItemKind::Method(..) => "trait method",
+                TraitItemKind::Fn(..) => "trait method",
                 TraitItemKind::Type(..) => "assoc type",
             };
 

src/librustc/middle/stability.rs

@@ -250,7 +250,7 @@ pub enum EvalResult {
 fn skip_stability_check_due_to_privacy(tcx: TyCtxt<'_>, mut def_id: DefId) -> bool {
     // Check if `def_id` is a trait method.
     match tcx.def_kind(def_id) {
-        Some(DefKind::Method) | Some(DefKind::AssocTy) | Some(DefKind::AssocConst) => {
+        Some(DefKind::AssocFn) | Some(DefKind::AssocTy) | Some(DefKind::AssocConst) => {
             if let ty::TraitContainer(trait_def_id) = tcx.associated_item(def_id).container {
                 // Trait methods do not declare visibility (even
                 // for visibility info in cstore). Use containing

src/librustc/mir/mod.rs

@@ -1446,7 +1446,7 @@ impl<'tcx> Debug for TerminatorKind<'tcx> {
         match successor_count {
             0 => Ok(()),
 
-            1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
+            1 => write!(fmt, " -> {:?}", self.successors().next().unwrap()),
 
             _ => {
                 write!(fmt, " -> [")?;
@@ -1827,9 +1827,9 @@ rustc_index::newtype_index! {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct PlaceRef<'a, 'tcx> {
+pub struct PlaceRef<'tcx> {
     pub local: Local,
-    pub projection: &'a [PlaceElem<'tcx>],
+    pub projection: &'tcx [PlaceElem<'tcx>],
 }
 
 impl<'tcx> Place<'tcx> {
@@ -1864,7 +1864,7 @@ impl<'tcx> Place<'tcx> {
         self.as_ref().as_local()
     }
 
-    pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
+    pub fn as_ref(&self) -> PlaceRef<'tcx> {
         PlaceRef { local: self.local, projection: &self.projection }
     }
 }
@@ -1875,7 +1875,7 @@ impl From<Local> for Place<'_> {
     }
 }
 
-impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
+impl<'tcx> PlaceRef<'tcx> {
     /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
     /// a single deref of a local.
     //

src/librustc/mir/mono.rs

@@ -258,7 +258,7 @@ pub enum Visibility {
 
 impl<'tcx> CodegenUnit<'tcx> {
     pub fn new(name: Symbol) -> CodegenUnit<'tcx> {
-        CodegenUnit { name: name, items: Default::default(), size_estimate: None }
+        CodegenUnit { name, items: Default::default(), size_estimate: None }
     }
 
     pub fn name(&self) -> Symbol {

src/librustc/traits/structural_impls.rs

@@ -532,9 +532,9 @@ impl<'a, 'tcx> Lift<'tcx> for traits::Vtable<'a, ()> {
                 nested,
             }) => tcx.lift(&substs).map(|substs| {
                 traits::VtableGenerator(traits::VtableGeneratorData {
-                    generator_def_id: generator_def_id,
-                    substs: substs,
-                    nested: nested,
+                    generator_def_id,
+                    substs,
+                    nested,
                 })
             }),
             traits::VtableClosure(traits::VtableClosureData { closure_def_id, substs, nested }) => {

src/librustc/ty/context.rs

@@ -611,7 +611,7 @@ impl<'tcx> TypeckTables<'tcx> {
         }
 
         match self.type_dependent_defs().get(expr.hir_id) {
-            Some(Ok((DefKind::Method, _))) => true,
+            Some(Ok((DefKind::AssocFn, _))) => true,
             _ => false,
         }
     }
@@ -2256,22 +2256,22 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn mk_mut_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ref(r, TypeAndMut { ty: ty, mutbl: hir::Mutability::Mut })
+        self.mk_ref(r, TypeAndMut { ty, mutbl: hir::Mutability::Mut })
     }
 
     #[inline]
     pub fn mk_imm_ref(self, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ref(r, TypeAndMut { ty: ty, mutbl: hir::Mutability::Not })
+        self.mk_ref(r, TypeAndMut { ty, mutbl: hir::Mutability::Not })
     }
 
     #[inline]
     pub fn mk_mut_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ptr(TypeAndMut { ty: ty, mutbl: hir::Mutability::Mut })
+        self.mk_ptr(TypeAndMut { ty, mutbl: hir::Mutability::Mut })
     }
 
     #[inline]
     pub fn mk_imm_ptr(self, ty: Ty<'tcx>) -> Ty<'tcx> {
-        self.mk_ptr(TypeAndMut { ty: ty, mutbl: hir::Mutability::Not })
+        self.mk_ptr(TypeAndMut { ty, mutbl: hir::Mutability::Not })
     }
 
     #[inline]
@@ -2393,7 +2393,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn mk_ty_param(self, index: u32, name: Symbol) -> Ty<'tcx> {
-        self.mk_ty(Param(ParamTy { index, name: name }))
+        self.mk_ty(Param(ParamTy { index, name }))
     }
 
     #[inline]

src/librustc/ty/instance.rs

@@ -241,7 +241,7 @@ impl<'tcx> Instance<'tcx> {
             def_id,
             substs
         );
-        Instance { def: InstanceDef::Item(def_id), substs: substs }
+        Instance { def: InstanceDef::Item(def_id), substs }
     }
 
     pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> {