Rollup of 15 pull requests

.mailmap

@@ -167,6 +167,8 @@ Matthijs Hofstra <thiezz@gmail.com>
 Melody Horn <melody@boringcactus.com> <mathphreak@gmail.com>
 Michael Williams <m.t.williams@live.com>
 Michael Woerister <michaelwoerister@posteo> <michaelwoerister@gmail>
+Michael Woerister <michaelwoerister@posteo> <michaelwoerister@users.noreply.github.com>
+Michael Woerister <michaelwoerister@posteo> <michaelwoerister@posteo.net>
 Mickaël Raybaud-Roig <raybaudroigm@gmail.com> m-r-r <raybaudroigm@gmail.com>
 Ms2ger <ms2ger@gmail.com> <Ms2ger@gmail.com>
 Mukilan Thiagarajan <mukilanthiagarajan@gmail.com>

src/doc/unstable-book/src/language-features/slice-patterns.md

@@ -1,8 +1,8 @@
 # `slice_patterns`
 
-The tracking issue for this feature is: [#23121]
+The tracking issue for this feature is: [#62254]
 
-[#23121]: https://github.com/rust-lang/rust/issues/23121
+[#62254]: https://github.com/rust-lang/rust/issues/62254
 
 ------------------------
 

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/boxed.rs

@@ -367,23 +367,35 @@ impl<T: Clone> Clone for Box<T> {
     /// ```
     /// let x = Box::new(5);
     /// let y = x.clone();
+    ///
+    /// // The value is the same
+    /// assert_eq!(x, y);
+    ///
+    /// // But they are unique objects
+    /// assert_ne!(&*x as *const i32, &*y as *const i32);
     /// ```
     #[rustfmt::skip]
     #[inline]
     fn clone(&self) -> Box<T> {
         box { (**self).clone() }
     }
+
     /// Copies `source`'s contents into `self` without creating a new allocation.
     ///
     /// # Examples
     ///
     /// ```
     /// let x = Box::new(5);
     /// let mut y = Box::new(10);
+    /// let yp: *const i32 = &*y;
     ///
     /// y.clone_from(&x);
     ///
-    /// assert_eq!(*y, 5);
+    /// // The value is the same
+    /// assert_eq!(x, y);
+    ///
+    /// // And no allocation occurred
+    /// assert_eq!(yp, &*y);
     /// ```
     #[inline]
     fn clone_from(&mut self, source: &Box<T>) {

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/slice/mod.rs

@@ -4453,6 +4453,21 @@ impl<'a, T> DoubleEndedIterator for ChunksExact<'a, T> {
             Some(snd)
         }
     }
+
+    #[inline]
+    fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
+        let len = self.len();
+        if n >= len {
+            self.v = &[];
+            None
+        } else {
+            let start = (len - 1 - n) * self.chunk_size;
+            let end = start + self.chunk_size;
+            let nth_back = &self.v[start..end];
+            self.v = &self.v[..start];
+            Some(nth_back)
+        }
+    }
 }
 
 #[stable(feature = "chunks_exact", since = "1.31.0")]

src/libcore/str/mod.rs

@@ -3716,10 +3716,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. 'Left' in this context means the first
-    /// position of that byte string; for a language like Arabic or Hebrew
-    /// which are 'right to left' rather than 'left to right', this will be
-    /// the _right_ side, not the left.
+    /// A string is a sequence of bytes. `start` in this context means the first
+    /// position of that byte string; for a left-to-right language like English or
+    /// Russian, this will be left side, and for right-to-left languages like
+    /// like Arabic or Hebrew, this will be the right side.
     ///
     /// # Examples
     ///
@@ -3755,10 +3755,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. 'Right' in this context means the last
-    /// position of that byte string; for a language like Arabic or Hebrew
-    /// which are 'right to left' rather than 'left to right', this will be
-    /// the _left_ side, not the right.
+    /// A string is a sequence of bytes. `end` in this context means the last
+    /// position of that byte string; for a left-to-right language like English or
+    /// Russian, this will be right side, and for right-to-left languages like
+    /// like Arabic or Hebrew, this will be the left side.
     ///
     /// # Examples
     ///
@@ -3804,10 +3804,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. `start` in this context means the first
-    /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be left side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the right side.
+    /// A string is a sequence of bytes. 'Left' in this context means the first
+    /// position of that byte string; for a language like Arabic or Hebrew
+    /// which are 'right to left' rather than 'left to right', this will be
+    /// the _right_ side, not the left.
     ///
     /// # Examples
     ///
@@ -3840,10 +3840,10 @@ impl str {
     ///
     /// # Text directionality
     ///
-    /// A string is a sequence of bytes. `end` in this context means the last
-    /// position of that byte string; for a left-to-right language like English or
-    /// Russian, this will be right side, and for right-to-left languages like
-    /// like Arabic or Hebrew, this will be the left side.
+    /// A string is a sequence of bytes. 'Right' in this context means the last
+    /// position of that byte string; for a language like Arabic or Hebrew
+    /// which are 'right to left' rather than 'left to right', this will be
+    /// the _left_ side, not the right.
     ///
     /// # Examples
     ///

src/libcore/tests/ascii.rs

@@ -151,7 +151,7 @@ macro_rules! assert_none {
                            stringify!($what), b);
                 }
             }
-        )*
+        )+
     }};
     ($what:ident, $($str:tt),+,) => (assert_none!($what,$($str),+))
 }

src/libcore/tests/pattern.rs

@@ -5,7 +5,7 @@ use std::str::pattern::*;
 macro_rules! search_asserts {
     ($haystack:expr, $needle:expr, $testname:expr, [$($func:ident),*], $result:expr) => {
         let mut searcher = $needle.into_searcher($haystack);
-        let arr = [$( Step::from(searcher.$func()) ),+];
+        let arr = [$( Step::from(searcher.$func()) ),*];
         assert_eq!(&arr[..], &$result, $testname);
     }
 }

src/libcore/tests/slice.rs

@@ -275,6 +275,25 @@ fn test_chunks_exact_nth() {
     assert_eq!(c2.next(), None);
 }
 
+#[test]
+fn test_chunks_exact_nth_back() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let mut c = v.chunks_exact(2);
+    assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next().unwrap(), &[0, 1]);
+    assert_eq!(c.next(), None);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4];
+    let mut c2 = v2.chunks_exact(3);
+    assert_eq!(c2.nth_back(0).unwrap(), &[0, 1, 2]);
+    assert_eq!(c2.next(), None);
+    assert_eq!(c2.next_back(), None);
+
+    let v3: &[i32] = &[0, 1, 2, 3, 4];
+    let mut c3 = v3.chunks_exact(10);
+    assert_eq!(c3.nth_back(0), None);
+}
+
 #[test]
 fn test_chunks_exact_last() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5];

src/librustc_codegen_ssa/back/link.rs

@@ -653,10 +653,14 @@ fn link_natively<'a, B: ArchiveBuilder<'a>>(sess: &'a Session,
             linker_error.emit();
 
             if sess.target.target.options.is_like_msvc && linker_not_found {
-                sess.note_without_error("the msvc targets depend on the msvc linker \
-                    but `link.exe` was not found");
-                sess.note_without_error("please ensure that VS 2013, VS 2015 or VS 2017 \
-                    was installed with the Visual C++ option");
+                sess.note_without_error(
+                    "the msvc targets depend on the msvc linker \
+                     but `link.exe` was not found",
+                );
+                sess.note_without_error(
+                    "please ensure that VS 2013, VS 2015, VS 2017 or VS 2019 \
+                     was installed with the Visual C++ option",
+                );
             }
             sess.abort_if_errors();
         }

src/librustc_interface/util.rs

@@ -642,14 +642,14 @@ pub fn build_output_filenames(
                 );
                 None
             } else {
+                if !sess.opts.cg.extra_filename.is_empty() {
+                    sess.warn("ignoring -C extra-filename flag due to -o flag");
+                }
                 Some(out_file.clone())
             };
             if *odir != None {
                 sess.warn("ignoring --out-dir flag due to -o flag");
             }
-            if !sess.opts.cg.extra_filename.is_empty() {
-                sess.warn("ignoring -C extra-filename flag due to -o flag");
-            }
 
             OutputFilenames {
                 out_directory: out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),

src/librustc_mir/interpret/cast.rs

@@ -1,7 +1,7 @@
 use rustc::ty::{self, Ty, TypeAndMut};
 use rustc::ty::layout::{self, TyLayout, Size};
 use rustc::ty::adjustment::{PointerCast};
-use syntax::ast::{FloatTy, IntTy, UintTy};
+use syntax::ast::FloatTy;
 use syntax::symbol::sym;
 
 use rustc_apfloat::ieee::{Single, Double};
@@ -151,7 +151,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpretCx<'mir, 'tcx, M> {
                     "Unexpected cast from type {:?}", src_layout.ty
                 );
                 match val.to_bits_or_ptr(src_layout.size, self) {
-                    Err(ptr) => self.cast_from_ptr(ptr, dest_layout.ty),
+                    Err(ptr) => self.cast_from_ptr(ptr, src_layout, dest_layout),
                     Ok(data) => self.cast_from_int(data, src_layout, dest_layout),
                 }
             }
@@ -239,17 +239,25 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpretCx<'mir, 'tcx, M> {
     fn cast_from_ptr(
         &self,
         ptr: Pointer<M::PointerTag>,
-        ty: Ty<'tcx>
+        src_layout: TyLayout<'tcx>,
+        dest_layout: TyLayout<'tcx>,
     ) -> InterpResult<'tcx, Scalar<M::PointerTag>> {
         use rustc::ty::TyKind::*;
-        match ty.sty {
+
+        match dest_layout.ty.sty {
             // Casting to a reference or fn pointer is not permitted by rustc,
             // no need to support it here.
-            RawPtr(_) |
-            Int(IntTy::Isize) |
-            Uint(UintTy::Usize) => Ok(ptr.into()),
-            Int(_) | Uint(_) => err!(ReadPointerAsBytes),
-            _ => err!(Unimplemented(format!("ptr to {:?} cast", ty))),
+            RawPtr(_) => Ok(ptr.into()),
+            Int(_) | Uint(_) => {
+                let size = self.memory.pointer_size();
+
+                match self.force_bits(Scalar::Ptr(ptr), size) {
+                    Ok(bits) => self.cast_from_int(bits, src_layout, dest_layout),
+                    Err(_) if dest_layout.size == size => Ok(ptr.into()),
+                    Err(e) => Err(e),
+                }
+            }
+            _ => bug!("invalid MIR: ptr to {:?} cast", dest_layout.ty)
         }
     }
 

src/librustc_target/spec/windows_msvc_base.rs

@@ -19,6 +19,10 @@ pub fn opts() -> TargetOptions {
         target_family: Some("windows".to_string()),
         is_like_windows: true,
         is_like_msvc: true,
+        // set VSLANG to 1033 can prevent link.exe from using
+        // language packs, and avoid generating Non-UTF-8 error
+        // messages if a link error occurred.
+        link_env: vec![("VSLANG".to_string(), "1033".to_string())],
         pre_link_args: args,
         crt_static_allows_dylibs: true,
         crt_static_respected: true,