Rollup of 16 pull requests

src/etc/gdb_load_rust_pretty_printers.py

@@ -1,2 +1,3 @@
+import gdb
 import gdb_rust_pretty_printing
 gdb_rust_pretty_printing.register_printers(gdb.current_objfile())

src/liballoc/vec.rs

@@ -1367,6 +1367,40 @@ impl<T> Vec<T> {
             self.truncate(new_len);
         }
     }
+
+    /// Consumes and leaks the `Vec`, returning a mutable reference to the contents,
+    /// `&'a mut [T]`. Note that the type `T` must outlive the chosen lifetime
+    /// `'a`. If the type has only static references, or none at all, then this
+    /// may be chosen to be `'static`.
+    ///
+    /// This function is similar to the `leak` function on `Box`.
+    ///
+    /// This function is mainly useful for data that lives for the remainder of
+    /// the program's life. Dropping the returned reference will cause a memory
+    /// leak.
+    ///
+    /// # Examples
+    ///
+    /// Simple usage:
+    ///
+    /// ```
+    /// #![feature(vec_leak)]
+    ///
+    /// fn main() {
+    ///     let x = vec![1, 2, 3];
+    ///     let static_ref: &'static mut [usize] = Vec::leak(x);
+    ///     static_ref[0] += 1;
+    ///     assert_eq!(static_ref, &[2, 2, 3]);
+    /// }
+    /// ```
+    #[unstable(feature = "vec_leak", issue = "62195")]
+    #[inline]
+    pub fn leak<'a>(vec: Vec<T>) -> &'a mut [T]
+    where
+        T: 'a // Technically not needed, but kept to be explicit.
+    {
+        Box::leak(vec.into_boxed_slice())
+    }
 }
 
 impl<T: Clone> Vec<T> {

src/libcore/convert.rs

@@ -251,12 +251,12 @@ pub trait AsMut<T: ?Sized> {
 ///
 /// # Examples
 ///
-/// [`String`] implements `Into<Vec<u8>>`:
+/// [`String`] implements [`Into`]`<`[`Vec`]`<`[`u8`]`>>`:
 ///
 /// In order to express that we want a generic function to take all arguments that can be
 /// converted to a specified type `T`, we can use a trait bound of [`Into`]`<T>`.
 /// For example: The function `is_hello` takes all arguments that can be converted into a
-/// `Vec<u8>`.
+/// [`Vec`]`<`[`u8`]`>`.
 ///
 /// ```
 /// fn is_hello<T: Into<Vec<u8>>>(s: T) {
@@ -274,6 +274,7 @@ pub trait AsMut<T: ?Sized> {
 /// [`String`]: ../../std/string/struct.String.html
 /// [`From`]: trait.From.html
 /// [`Into`]: trait.Into.html
+/// [`Vec`]: ../../std/vec/struct.Vec.html
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Into<T>: Sized {
     /// Performs the conversion.
@@ -410,12 +411,12 @@ pub trait TryInto<T>: Sized {
 ///
 /// This is useful when you are doing a type conversion that may
 /// trivially succeed but may also need special handling.
-/// For example, there is no way to convert an `i64` into an `i32`
-/// using the [`From`] trait, because an `i64` may contain a value
-/// that an `i32` cannot represent and so the conversion would lose data.
-/// This might be handled by truncating the `i64` to an `i32` (essentially
-/// giving the `i64`'s value modulo `i32::MAX`) or by simply returning
-/// `i32::MAX`, or by some other method.  The `From` trait is intended
+/// For example, there is no way to convert an [`i64`] into an [`i32`]
+/// using the [`From`] trait, because an [`i64`] may contain a value
+/// that an [`i32`] cannot represent and so the conversion would lose data.
+/// This might be handled by truncating the [`i64`] to an [`i32`] (essentially
+/// giving the [`i64`]'s value modulo [`i32::MAX`]) or by simply returning
+/// [`i32::MAX`], or by some other method.  The [`From`] trait is intended
 /// for perfect conversions, so the `TryFrom` trait informs the
 /// programmer when a type conversion could go bad and lets them
 /// decide how to handle it.
@@ -425,8 +426,8 @@ pub trait TryInto<T>: Sized {
 /// - `TryFrom<T> for U` implies [`TryInto`]`<U> for T`
 /// - [`try_from`] is reflexive, which means that `TryFrom<T> for T`
 /// is implemented and cannot fail -- the associated `Error` type for
-/// calling `T::try_from()` on a value of type `T` is `Infallible`.
-/// When the `!` type is stablized `Infallible` and `!` will be
+/// calling `T::try_from()` on a value of type `T` is [`Infallible`].
+/// When the [`!`] type is stablized [`Infallible`] and [`!`] will be
 /// equivalent.
 ///
 /// `TryFrom<T>` can be implemented as follows:
@@ -451,7 +452,7 @@ pub trait TryInto<T>: Sized {
 ///
 /// # Examples
 ///
-/// As described, [`i32`] implements `TryFrom<i64>`:
+/// As described, [`i32`] implements `TryFrom<`[`i64`]`>`:
 ///
 /// ```
 /// use std::convert::TryFrom;
@@ -474,6 +475,8 @@ pub trait TryInto<T>: Sized {
 ///
 /// [`try_from`]: trait.TryFrom.html#tymethod.try_from
 /// [`TryInto`]: trait.TryInto.html
+/// [`i32::MAX`]: ../../std/i32/constant.MAX.html
+/// [`!`]: ../../std/primitive.never.html
 #[stable(feature = "try_from", since = "1.34.0")]
 pub trait TryFrom<T>: Sized {
     /// The type returned in the event of a conversion error.

src/libcore/intrinsics.rs

@@ -36,6 +36,8 @@
             issue = "0")]
 #![allow(missing_docs)]
 
+use crate::mem;
+
 #[stable(feature = "drop_in_place", since = "1.8.0")]
 #[rustc_deprecated(reason = "no longer an intrinsic - use `ptr::drop_in_place` directly",
                    since = "1.18.0")]
@@ -1331,6 +1333,26 @@ extern "rust-intrinsic" {
 // (`transmute` also falls into this category, but it cannot be wrapped due to the
 // check that `T` and `U` have the same size.)
 
+/// Checks whether `ptr` is properly aligned with respect to
+/// `align_of::<T>()`.
+pub(crate) fn is_aligned_and_not_null<T>(ptr: *const T) -> bool {
+    !ptr.is_null() && ptr as usize % mem::align_of::<T>() == 0
+}
+
+/// Checks whether the regions of memory starting at `src` and `dst` of size
+/// `count * size_of::<T>()` overlap.
+fn overlaps<T>(src: *const T, dst: *const T, count: usize) -> bool {
+    let src_usize = src as usize;
+    let dst_usize = dst as usize;
+    let size = mem::size_of::<T>().checked_mul(count).unwrap();
+    let diff = if src_usize > dst_usize {
+        src_usize - dst_usize
+    } else {
+        dst_usize - src_usize
+    };
+    size > diff
+}
+
 /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
 /// and destination must *not* overlap.
 ///
@@ -1420,7 +1442,11 @@ pub unsafe fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize) {
     extern "rust-intrinsic" {
         fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
     }
-    copy_nonoverlapping(src, dst, count);
+
+    debug_assert!(is_aligned_and_not_null(src), "attempt to copy from unaligned or null pointer");
+    debug_assert!(is_aligned_and_not_null(dst), "attempt to copy to unaligned or null pointer");
+    debug_assert!(!overlaps(src, dst, count), "attempt to copy to overlapping memory");
+    copy_nonoverlapping(src, dst, count)
 }
 
 /// Copies `count * size_of::<T>()` bytes from `src` to `dst`. The source
@@ -1480,6 +1506,9 @@ pub unsafe fn copy<T>(src: *const T, dst: *mut T, count: usize) {
     extern "rust-intrinsic" {
         fn copy<T>(src: *const T, dst: *mut T, count: usize);
     }
+
+    debug_assert!(is_aligned_and_not_null(src), "attempt to copy from unaligned or null pointer");
+    debug_assert!(is_aligned_and_not_null(dst), "attempt to copy to unaligned or null pointer");
     copy(src, dst, count)
 }
 
@@ -1561,6 +1590,8 @@ pub unsafe fn write_bytes<T>(dst: *mut T, val: u8, count: usize) {
     extern "rust-intrinsic" {
         fn write_bytes<T>(dst: *mut T, val: u8, count: usize);
     }
+
+    debug_assert!(is_aligned_and_not_null(dst), "attempt to write to unaligned or null pointer");
     write_bytes(dst, val, count)
 }
 

src/libcore/lib.rs

@@ -74,6 +74,7 @@
 #![feature(concat_idents)]
 #![feature(const_fn)]
 #![feature(const_fn_union)]
+#![feature(custom_inner_attributes)]
 #![feature(doc_cfg)]
 #![feature(doc_spotlight)]
 #![feature(extern_types)]

src/libcore/slice/mod.rs

@@ -25,7 +25,7 @@
 use crate::cmp::Ordering::{self, Less, Equal, Greater};
 use crate::cmp;
 use crate::fmt;
-use crate::intrinsics::{assume, exact_div, unchecked_sub};
+use crate::intrinsics::{assume, exact_div, unchecked_sub, is_aligned_and_not_null};
 use crate::isize;
 use crate::iter::*;
 use crate::ops::{FnMut, Try, self};
@@ -5213,7 +5213,7 @@ unsafe impl<'a, T> TrustedRandomAccess for RChunksExactMut<'a, T> {
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T] {
-    debug_assert!(data as usize % mem::align_of::<T>() == 0, "attempt to create unaligned slice");
+    debug_assert!(is_aligned_and_not_null(data), "attempt to create unaligned or null slice");
     debug_assert!(mem::size_of::<T>().saturating_mul(len) <= isize::MAX as usize,
                   "attempt to create slice covering half the address space");
     &*ptr::slice_from_raw_parts(data, len)
@@ -5234,7 +5234,7 @@ pub unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T] {
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub unsafe fn from_raw_parts_mut<'a, T>(data: *mut T, len: usize) -> &'a mut [T] {
-    debug_assert!(data as usize % mem::align_of::<T>() == 0, "attempt to create unaligned slice");
+    debug_assert!(is_aligned_and_not_null(data), "attempt to create unaligned or null slice");
     debug_assert!(mem::size_of::<T>().saturating_mul(len) <= isize::MAX as usize,
                   "attempt to create slice covering half the address space");
     &mut *ptr::slice_from_raw_parts_mut(data, len)

src/libproc_macro/bridge/scoped_cell.rs

@@ -74,7 +74,7 @@ impl<T: LambdaL> ScopedCell<T> {
     }
 
     /// Sets the value in `self` to `value` while running `f`.
-    pub fn set<'a, R>(&self, value: <T as ApplyL<'a>>::Out, f: impl FnOnce() -> R) -> R {
+    pub fn set<R>(&self, value: <T as ApplyL<'_>>::Out, f: impl FnOnce() -> R) -> R {
         self.replace(value, |_| f())
     }
 }

src/librustc/cfg/construct.rs

@@ -1,11 +1,11 @@
 use crate::cfg::*;
 use crate::middle::region;
 use rustc_data_structures::graph::implementation as graph;
-use syntax::ptr::P;
 use crate::ty::{self, TyCtxt};
 
 use crate::hir::{self, PatKind};
 use crate::hir::def_id::DefId;
+use crate::hir::ptr::P;
 
 struct CFGBuilder<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
@@ -30,7 +30,7 @@ struct LoopScope {
     break_index: CFGIndex,    // where to go on a `break`
 }
 
-pub fn construct<'tcx>(tcx: TyCtxt<'tcx>, body: &hir::Body) -> CFG {
+pub fn construct(tcx: TyCtxt<'_>, body: &hir::Body) -> CFG {
     let mut graph = graph::Graph::new();
     let entry = graph.add_node(CFGNodeData::Entry);
 

src/librustc/cfg/mod.rs

@@ -49,7 +49,7 @@ pub type CFGNode = graph::Node<CFGNodeData>;
 pub type CFGEdge = graph::Edge<CFGEdgeData>;
 
 impl CFG {
-    pub fn new<'tcx>(tcx: TyCtxt<'tcx>, body: &hir::Body) -> CFG {
+    pub fn new(tcx: TyCtxt<'_>, body: &hir::Body) -> CFG {
         construct::construct(tcx, body)
     }
 

src/librustc/dep_graph/graph.rs

@@ -841,7 +841,7 @@ impl DepGraph {
     //
     // This method will only load queries that will end up in the disk cache.
     // Other queries will not be executed.
-    pub fn exec_cache_promotions<'tcx>(&self, tcx: TyCtxt<'tcx>) {
+    pub fn exec_cache_promotions(&self, tcx: TyCtxt<'_>) {
         let data = self.data.as_ref().unwrap();
         for prev_index in data.colors.values.indices() {
             match data.colors.get(prev_index) {

src/librustc/hir/check_attr.rs

@@ -347,7 +347,7 @@ fn is_c_like_enum(item: &hir::Item) -> bool {
     }
 }
 
-fn check_mod_attrs<'tcx>(tcx: TyCtxt<'tcx>, module_def_id: DefId) {
+fn check_mod_attrs(tcx: TyCtxt<'_>, module_def_id: DefId) {
     tcx.hir().visit_item_likes_in_module(
         module_def_id,
         &mut CheckAttrVisitor { tcx }.as_deep_visitor()

src/librustc/hir/lowering.rs

@@ -39,6 +39,7 @@ use crate::hir::map::{DefKey, DefPathData, Definitions};
 use crate::hir::def_id::{DefId, DefIndex, CRATE_DEF_INDEX};
 use crate::hir::def::{Res, DefKind, PartialRes, PerNS};
 use crate::hir::{GenericArg, ConstArg};
+use crate::hir::ptr::P;
 use crate::lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
                     ELIDED_LIFETIMES_IN_PATHS};
 use crate::middle::cstore::CrateStore;
@@ -61,7 +62,6 @@ use syntax::ast::*;
 use syntax::errors;
 use syntax::ext::hygiene::{Mark, SyntaxContext};
 use syntax::print::pprust;
-use syntax::ptr::P;
 use syntax::source_map::{self, respan, ExpnInfo, CompilerDesugaringKind, Spanned};
 use syntax::source_map::CompilerDesugaringKind::IfTemporary;
 use syntax::std_inject;
@@ -1111,7 +1111,7 @@ impl<'a> LoweringContext<'a> {
             },
         );
 
-        lowered_generics.params = lowered_generics
+        let mut lowered_params: Vec<_> = lowered_generics
             .params
             .into_iter()
             .chain(in_band_defs)
@@ -1121,14 +1121,16 @@ impl<'a> LoweringContext<'a> {
         // unsorted generic parameters at the moment, so we make sure
         // that they're ordered correctly here for now. (When we chain
         // the `in_band_defs`, we might make the order unsorted.)
-        lowered_generics.params.sort_by_key(|param| {
+        lowered_params.sort_by_key(|param| {
             match param.kind {
                 hir::GenericParamKind::Lifetime { .. } => ParamKindOrd::Lifetime,
                 hir::GenericParamKind::Type { .. } => ParamKindOrd::Type,
                 hir::GenericParamKind::Const { .. } => ParamKindOrd::Const,
             }
         });
 
+        lowered_generics.params = lowered_params.into();
+
         (lowered_generics, res)
     }
 
@@ -1155,13 +1157,13 @@ impl<'a> LoweringContext<'a> {
         &mut self,
         capture_clause: CaptureBy,
         closure_node_id: NodeId,
-        ret_ty: Option<&Ty>,
+        ret_ty: Option<syntax::ptr::P<Ty>>,
         span: Span,
         body: impl FnOnce(&mut LoweringContext<'_>) -> hir::Expr,
     ) -> hir::ExprKind {
         let capture_clause = self.lower_capture_clause(capture_clause);
         let output = match ret_ty {
-            Some(ty) => FunctionRetTy::Ty(P(ty.clone())),
+            Some(ty) => FunctionRetTy::Ty(ty),
             None => FunctionRetTy::Default(span),
         };
         let ast_decl = FnDecl {
@@ -2725,7 +2727,7 @@ impl<'a> LoweringContext<'a> {
 
         // ::std::future::Future<future_params>
         let future_path =
-            self.std_path(span, &[sym::future, sym::Future], Some(future_params), false);
+            P(self.std_path(span, &[sym::future, sym::Future], Some(future_params), false));
 
         hir::GenericBound::Trait(
             hir::PolyTraitRef {
@@ -3094,7 +3096,7 @@ impl<'a> LoweringContext<'a> {
 
     fn lower_trait_ref(&mut self, p: &TraitRef, itctx: ImplTraitContext<'_>) -> hir::TraitRef {
         let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) {
-            hir::QPath::Resolved(None, path) => path.and_then(|path| path),
+            hir::QPath::Resolved(None, path) => path,
             qpath => bug!("lower_trait_ref: unexpected QPath `{:?}`", qpath),
         };
         hir::TraitRef {
@@ -3620,7 +3622,7 @@ impl<'a> LoweringContext<'a> {
                             hir::Item {
                                 hir_id: new_id,
                                 ident,
-                                attrs: attrs.clone(),
+                                attrs: attrs.into_iter().cloned().collect(),
                                 node: item,
                                 vis,
                                 span,
@@ -3705,7 +3707,7 @@ impl<'a> LoweringContext<'a> {
                             hir::Item {
                                 hir_id: new_hir_id,
                                 ident,
-                                attrs: attrs.clone(),
+                                attrs: attrs.into_iter().cloned().collect(),
                                 node: item,
                                 vis,
                                 span: use_tree.span,
@@ -4567,7 +4569,7 @@ impl<'a> LoweringContext<'a> {
                         // `|x: u8| future_from_generator(|| -> X { ... })`.
                         let body_id = this.lower_fn_body(&outer_decl, |this| {
                             let async_ret_ty = if let FunctionRetTy::Ty(ty) = &decl.output {
-                                Some(&**ty)
+                                Some(ty.clone())
                             } else { None };
                             let async_body = this.make_async_expr(
                                 capture_clause, closure_id, async_ret_ty, body.span,
@@ -5577,7 +5579,7 @@ impl<'a> LoweringContext<'a> {
                         let principal = hir::PolyTraitRef {
                             bound_generic_params: hir::HirVec::new(),
                             trait_ref: hir::TraitRef {
-                                path: path.and_then(|path| path),
+                                path,
                                 hir_ref_id: hir_id,
                             },
                             span,

src/librustc/hir/map/hir_id_validator.rs

@@ -4,7 +4,7 @@ use crate::hir::itemlikevisit::ItemLikeVisitor;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::sync::{Lock, ParallelIterator, par_iter};
 
-pub fn check_crate<'hir>(hir_map: &hir::map::Map<'hir>) {
+pub fn check_crate(hir_map: &hir::map::Map<'_>) {
     hir_map.dep_graph.assert_ignored();
 
     let errors = Lock::new(Vec::new());