Auto merge of #40972 - frewsxcv:rollup, r=frewsxcv

Rollup of 6 pull requests

- Successful merges: #40703, #40728, #40763, #40871, #40935, #40947
- Failed merges:

src/libcollections/str.rs

@@ -133,9 +133,15 @@ impl<S: Borrow<str>> SliceConcatExt<str> for [S] {
     }
 }
 
-/// External iterator for a string's UTF-16 code units.
+/// An iterator of [`u16`] over the string encoded as UTF-16.
 ///
-/// For use with the `std::iter` module.
+/// [`u16`]: ../../std/primitive.u16.html
+///
+/// This struct is created by the [`encode_utf16`] method on [`str`].
+/// See its documentation for more.
+///
+/// [`encode_utf16`]: ../../std/primitive.str.html#method.encode_utf16
+/// [`str`]: ../../std/primitive.str.html
 #[derive(Clone)]
 #[stable(feature = "encode_utf16", since = "1.8.0")]
 pub struct EncodeUtf16<'a> {

src/libcollectionstest/slice.rs

@@ -383,9 +383,11 @@ fn test_reverse() {
 
 #[test]
 fn test_sort() {
+    let mut rng = thread_rng();
+
     for len in (2..25).chain(500..510) {
         for _ in 0..100 {
-            let mut v: Vec<_> = thread_rng().gen_iter::<i32>().take(len).collect();
+            let mut v: Vec<_> = rng.gen_iter::<i32>().take(len).collect();
             let mut v1 = v.clone();
 
             v.sort();
@@ -399,6 +401,18 @@ fn test_sort() {
         }
     }
 
+    // Sort using a completely random comparison function.
+    // This will reorder the elements *somehow*, but won't panic.
+    let mut v = [0; 500];
+    for i in 0..v.len() {
+        v[i] = i as i32;
+    }
+    v.sort_by(|_, _| *rng.choose(&[Less, Equal, Greater]).unwrap());
+    v.sort();
+    for i in 0..v.len() {
+        assert_eq!(v[i], i as i32);
+    }
+
     // Should not panic.
     [0i32; 0].sort();
     [(); 10].sort();

src/libcore/str/mod.rs

@@ -369,11 +369,15 @@ impl fmt::Display for Utf8Error {
 Section: Iterators
 */
 
-/// Iterator for the char (representing *Unicode Scalar Values*) of a string.
+/// An iterator over the [`char`]s of a string slice.
 ///
-/// Created with the method [`chars`].
+/// [`char`]: ../../std/primitive.char.html
+///
+/// This struct is created by the [`chars`] method on [`str`].
+/// See its documentation for more.
 ///
 /// [`chars`]: ../../std/primitive.str.html#method.chars
+/// [`str`]: ../../std/primitive.str.html
 #[derive(Clone, Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct Chars<'a> {
@@ -553,7 +557,15 @@ impl<'a> Chars<'a> {
     }
 }
 
-/// Iterator for a string's characters and their byte offsets.
+/// An iterator over the [`char`]s of a string slice, and their positions.
+///
+/// [`char`]: ../../std/primitive.char.html
+///
+/// This struct is created by the [`char_indices`] method on [`str`].
+/// See its documentation for more.
+///
+/// [`char_indices`]: ../../std/primitive.str.html#method.char_indices
+/// [`str`]: ../../std/primitive.str.html
 #[derive(Clone, Debug)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct CharIndices<'a> {
@@ -625,12 +637,13 @@ impl<'a> CharIndices<'a> {
     }
 }
 
-/// External iterator for a string's bytes.
-/// Use with the `std::iter` module.
+/// An iterator over the bytes of a string slice.
 ///
-/// Created with the method [`bytes`].
+/// This struct is created by the [`bytes`] method on [`str`].
+/// See its documentation for more.
 ///
 /// [`bytes`]: ../../std/primitive.str.html#method.bytes
+/// [`str`]: ../../std/primitive.str.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[derive(Clone, Debug)]
 pub struct Bytes<'a>(Cloned<slice::Iter<'a, u8>>);
@@ -1161,9 +1174,13 @@ generate_pattern_iterators! {
     delegate double ended;
 }
 
-/// Created with the method [`lines`].
+/// An iterator over the lines of a string, as string slices.
+///
+/// This struct is created with the [`lines`] method on [`str`].
+/// See its documentation for more.
 ///
 /// [`lines`]: ../../std/primitive.str.html#method.lines
+/// [`str`]: ../../std/primitive.str.html
 #[stable(feature = "rust1", since = "1.0.0")]
 #[derive(Clone, Debug)]
 pub struct Lines<'a>(Map<SplitTerminator<'a, char>, LinesAnyMap>);

src/libcore/sync/atomic.rs

@@ -15,27 +15,37 @@
 //! types.
 //!
 //! This module defines atomic versions of a select number of primitive
-//! types, including `AtomicBool`, `AtomicIsize`, and `AtomicUsize`.
+//! types, including [`AtomicBool`], [`AtomicIsize`], and [`AtomicUsize`].
 //! Atomic types present operations that, when used correctly, synchronize
 //! updates between threads.
 //!
-//! Each method takes an `Ordering` which represents the strength of
+//! [`AtomicBool`]: struct.AtomicBool.html
+//! [`AtomicIsize`]: struct.AtomicIsize.html
+//! [`AtomicUsize`]: struct.AtomicUsize.html
+//!
+//! Each method takes an [`Ordering`] which represents the strength of
 //! the memory barrier for that operation. These orderings are the
 //! same as [LLVM atomic orderings][1]. For more information see the [nomicon][2].
 //!
+//! [`Ordering`]: enum.Ordering.html
+//!
 //! [1]: http://llvm.org/docs/LangRef.html#memory-model-for-concurrent-operations
 //! [2]: ../../../nomicon/atomics.html
 //!
-//! Atomic variables are safe to share between threads (they implement `Sync`)
+//! Atomic variables are safe to share between threads (they implement [`Sync`])
 //! but they do not themselves provide the mechanism for sharing and follow the
 //! [threading model](../../../std/thread/index.html#the-threading-model) of rust.
-//! The most common way to share an atomic variable is to put it into an `Arc` (an
+//! The most common way to share an atomic variable is to put it into an [`Arc`][arc] (an
 //! atomically-reference-counted shared pointer).
 //!
+//! [`Sync`]: ../../marker/trait.Sync.html
+//! [arc]: ../../../std/sync/struct.Arc.html
+//!
 //! Most atomic types may be stored in static variables, initialized using
-//! the provided static initializers like `ATOMIC_BOOL_INIT`. Atomic statics
+//! the provided static initializers like [`ATOMIC_BOOL_INIT`]. Atomic statics
 //! are often used for lazy global initialization.
 //!
+//! [`ATOMIC_BOOL_INIT`]: constant.ATOMIC_BOOL_INIT.html
 //!
 //! # Examples
 //!
@@ -148,22 +158,32 @@ unsafe impl<T> Sync for AtomicPtr<T> {}
 #[stable(feature = "rust1", since = "1.0.0")]
 #[derive(Copy, Clone, Debug)]
 pub enum Ordering {
-    /// No ordering constraints, only atomic operations. Corresponds to LLVM's
-    /// `Monotonic` ordering.
+    /// No ordering constraints, only atomic operations.
+    ///
+    /// Corresponds to LLVM's [`Monotonic`] ordering.
+    ///
+    /// [`Monotonic`]: http://llvm.org/docs/Atomics.html#monotonic
     #[stable(feature = "rust1", since = "1.0.0")]
     Relaxed,
     /// When coupled with a store, all previous writes become visible
-    /// to the other threads that perform a load with `Acquire` ordering
+    /// to the other threads that perform a load with [`Acquire`] ordering
     /// on the same value.
+    ///
+    /// [`Acquire`]: http://llvm.org/docs/Atomics.html#acquire
     #[stable(feature = "rust1", since = "1.0.0")]
     Release,
     /// When coupled with a load, all subsequent loads will see data
-    /// written before a store with `Release` ordering on the same value
+    /// written before a store with [`Release`] ordering on the same value
     /// in other threads.
+    ///
+    /// [`Release`]: http://llvm.org/docs/Atomics.html#release
     #[stable(feature = "rust1", since = "1.0.0")]
     Acquire,
-    /// When coupled with a load, uses `Acquire` ordering, and with a store
-    /// `Release` ordering.
+    /// When coupled with a load, uses [`Acquire`] ordering, and with a store
+    /// [`Release`] ordering.
+    ///
+    /// [`Acquire`]: http://llvm.org/docs/Atomics.html#acquire
+    /// [`Release`]: http://llvm.org/docs/Atomics.html#release
     #[stable(feature = "rust1", since = "1.0.0")]
     AcqRel,
     /// Like `AcqRel` with the additional guarantee that all threads see all
@@ -176,7 +196,9 @@ pub enum Ordering {
     __Nonexhaustive,
 }
 
-/// An `AtomicBool` initialized to `false`.
+/// An [`AtomicBool`] initialized to `false`.
+///
+/// [`AtomicBool`]: struct.AtomicBool.html
 #[cfg(target_has_atomic = "8")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub const ATOMIC_BOOL_INIT: AtomicBool = AtomicBool::new(false);
@@ -250,7 +272,7 @@ impl AtomicBool {
     ///
     /// [`Ordering`]: enum.Ordering.html
     /// [`Release`]: enum.Ordering.html#variant.Release
-    /// [`AcqRel`]: enum.Ordering.html#variant.Release
+    /// [`AcqRel`]: enum.Ordering.html#variant.AcqRel
     ///
     /// # Examples
     ///
@@ -287,7 +309,10 @@ impl AtomicBool {
     ///
     /// # Panics
     ///
-    /// Panics if `order` is `Acquire` or `AcqRel`.
+    /// Panics if `order` is [`Acquire`] or [`AcqRel`].
+    ///
+    /// [`Acquire`]: enum.Ordering.html#variant.Acquire
+    /// [`AcqRel`]: enum.Ordering.html#variant.AcqRel
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn store(&self, val: bool, order: Ordering) {
@@ -404,7 +429,7 @@ impl AtomicBool {
 
     /// Stores a value into the `bool` if the current value is the same as the `current` value.
     ///
-    /// Unlike `compare_exchange`, this function is allowed to spuriously fail even when the
+    /// Unlike [`compare_exchange`], this function is allowed to spuriously fail even when the
     /// comparison succeeds, which can result in more efficient code on some platforms. The
     /// return value is a result indicating whether the new value was written and containing the
     /// previous value.
@@ -415,6 +440,7 @@ impl AtomicBool {
     /// failure ordering can't be [`Release`] or [`AcqRel`] and must be equivalent or
     /// weaker than the success ordering.
     ///
+    /// [`compare_exchange`]: #method.compare_exchange
     /// [`Ordering`]: enum.Ordering.html
     /// [`Release`]: enum.Ordering.html#variant.Release
     /// [`AcqRel`]: enum.Ordering.html#variant.Release
@@ -694,7 +720,10 @@ impl<T> AtomicPtr<T> {
     ///
     /// # Panics
     ///
-    /// Panics if `order` is `Acquire` or `AcqRel`.
+    /// Panics if `order` is [`Acquire`] or [`AcqRel`].
+    ///
+    /// [`Acquire`]: enum.Ordering.html#variant.Acquire
+    /// [`AcqRel`]: enum.Ordering.html#variant.AcqRel
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn store(&self, ptr: *mut T, order: Ordering) {
@@ -1008,7 +1037,10 @@ macro_rules! atomic_int {
             ///
             /// # Panics
             ///
-            /// Panics if `order` is `Acquire` or `AcqRel`.
+            /// Panics if `order` is [`Acquire`] or [`AcqRel`].
+            ///
+            /// [`Acquire`]: enum.Ordering.html#variant.Acquire
+            /// [`AcqRel`]: enum.Ordering.html#variant.AcqRel
             #[inline]
             #[$stable]
             pub fn store(&self, val: $int_type, order: Ordering) {

src/libcoretest/slice.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use core::cmp::Ordering::{Equal, Greater, Less};
 use core::slice::heapsort;
 use core::result::Result::{Ok, Err};
 use rand::{Rng, XorShiftRng};
@@ -268,6 +269,17 @@ fn sort_unstable() {
         }
     }
 
+    // Sort using a completely random comparison function.
+    // This will reorder the elements *somehow*, but won't panic.
+    for i in 0..v.len() {
+        v[i] = i as i32;
+    }
+    v.sort_unstable_by(|_, _| *rng.choose(&[Less, Equal, Greater]).unwrap());
+    v.sort_unstable();
+    for i in 0..v.len() {
+        assert_eq!(v[i], i as i32);
+    }
+
     // Should not panic.
     [0i32; 0].sort_unstable();
     [(); 10].sort_unstable();

src/librustc_lint/lib.rs

@@ -196,10 +196,6 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
             id: LintId::of(SUPER_OR_SELF_IN_GLOBAL_PATH),
             reference: "issue #36888 <https://github.com/rust-lang/rust/issues/36888>",
         },
-        FutureIncompatibleInfo {
-            id: LintId::of(OVERLAPPING_INHERENT_IMPLS),
-            reference: "issue #36889 <https://github.com/rust-lang/rust/issues/36889>",
-        },
         FutureIncompatibleInfo {
             id: LintId::of(ILLEGAL_FLOATING_POINT_CONSTANT_PATTERN),
             reference: "issue #36890 <https://github.com/rust-lang/rust/issues/36890>",
@@ -263,4 +259,5 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
     store.register_removed("drop_with_repr_extern", "drop flags have been removed");
     store.register_removed("transmute_from_fn_item_types",
         "always cast functions before transmuting them");
+    store.register_removed("overlapping_inherent_impls", "converted into hard error, see #36889");
 }

src/librustc_typeck/coherence/inherent_impls.rs

@@ -322,4 +322,3 @@ impl<'a, 'tcx> InherentCollect<'a, 'tcx> {
         }
     }
 }
-

src/librustc_typeck/diagnostics.rs

@@ -4212,4 +4212,5 @@ register_diagnostics! {
            // but `{}` was found in the type `{}`
     E0567, // auto traits can not have type parameters
     E0568, // auto-traits can not have predicates,
+    E0592, // duplicate definitions with name `{}`
 }

src/libstd/io/mod.rs

@@ -145,6 +145,18 @@
 //! # }
 //! ```
 //!
+//! Note that you cannot use the `?` operator in functions that do not return
+//! a `Result<T, E>` (e.g. `main`). Instead, you can call `.unwrap()` or `match`
+//! on the return value to catch any possible errors:
+//!
+//! ```
+//! use std::io;
+//!
+//! let mut input = String::new();
+//!
+//! io::stdin().read_line(&mut input).unwrap();
+//! ```
+//!
 //! And a very common source of output is standard output:
 //!
 //! ```

src/libstd/primitive_docs.rs

@@ -183,9 +183,9 @@ mod prim_unit { }
 /// Working with raw pointers in Rust is uncommon,
 /// typically limited to a few patterns.
 ///
-/// Use the `null` function to create null pointers, and the `is_null` method
+/// Use the [`null`] function to create null pointers, and the [`is_null`] method
 /// of the `*const T` type  to check for null. The `*const T` type also defines
-/// the `offset` method, for pointer math.
+/// the [`offset`] method, for pointer math.
 ///
 /// # Common ways to create raw pointers
 ///
@@ -213,7 +213,7 @@ mod prim_unit { }
 ///
 /// ## 2. Consume a box (`Box<T>`).
 ///
-/// The `into_raw` function consumes a box and returns
+/// The [`into_raw`] function consumes a box and returns
 /// the raw pointer. It doesn't destroy `T` or deallocate any memory.
 ///
 /// ```
@@ -227,7 +227,7 @@ mod prim_unit { }
 /// }
 /// ```
 ///
-/// Note that here the call to `drop` is for clarity - it indicates
+/// Note that here the call to [`drop`] is for clarity - it indicates
 /// that we are done with the given value and it should be destroyed.
 ///
 /// ## 3. Get it from C.
@@ -255,6 +255,11 @@ mod prim_unit { }
 ///
 /// *[See also the `std::ptr` module](ptr/index.html).*
 ///
+/// [`null`]: ../std/ptr/fn.null.html
+/// [`is_null`]: ../std/primitive.pointer.html#method.is_null
+/// [`offset`]: ../std/primitive.pointer.html#method.offset
+/// [`into_raw`]: ../std/boxed/struct.Box.html#method.into_raw
+/// [`drop`]: ../std/mem/fn.drop.html
 #[stable(feature = "rust1", since = "1.0.0")]
 mod prim_pointer { }
 

src/libstd_unicode/u_str.rs

@@ -19,6 +19,12 @@ use core::str::Split;
 
 /// An iterator over the non-whitespace substrings of a string,
 /// separated by any amount of whitespace.
+///
+/// This struct is created by the [`split_whitespace`] method on [`str`].
+/// See its documentation for more.
+///
+/// [`split_whitespace`]: ../../std/primitive.str.html#method.split_whitespace
+/// [`str`]: ../../std/primitive.str.html
 #[stable(feature = "split_whitespace", since = "1.1.0")]
 pub struct SplitWhitespace<'a> {
     inner: Filter<Split<'a, fn(char) -> bool>, fn(&&str) -> bool>,

src/test/compile-fail/coherence-overlapping-inherent-impl-trait.rs

@@ -9,10 +9,8 @@
 // except according to those terms.
 
 #![allow(dead_code)]
-#![deny(overlapping_inherent_impls)]
 
 trait C {}
 impl C { fn f() {} } //~ ERROR duplicate definitions with name `f`
-//~^ WARN: this was previously accepted
 impl C { fn f() {} }
 fn main() { }

src/test/compile-fail/inherent-overlap.rs

@@ -17,7 +17,6 @@ struct Foo;
 
 impl Foo {
     fn id() {} //~ ERROR duplicate definitions
-    //~^ WARN previously accepted
 }
 
 impl Foo {
@@ -28,7 +27,6 @@ struct Bar<T>(T);
 
 impl<T> Bar<T> {
     fn bar(&self) {} //~ ERROR duplicate definitions
-    //~^ WARN previously accepted
 }
 
 impl Bar<u32> {
@@ -39,7 +37,6 @@ struct Baz<T>(T);
 
 impl<T: Copy> Baz<T> {
     fn baz(&self) {} //~ ERROR duplicate definitions
-    //~^ WARN previously accepted
 }
 
 impl<T> Baz<Vec<T>> {