Auto merge of #58578 - kennytm:rollup, r=kennytm

Rollup of 24 pull requests

Successful merges:

 - #56470 (Modify doctest's auto-`fn main()` to allow `Result`s)
 - #58044 (Make overflowing and wrapping negation const)
 - #58303 (Improve stability tags display)
 - #58336 (Fix search results interactions)
 - #58384 (Fix tables display)
 - #58392 (Use less explicit shifting in std::net::ip)
 - #58409 (rustdoc: respect alternate flag when formatting impl trait)
 - #58456 (Remove no longer accurate diagnostic code about NLL)
 - #58528 (Don't use an allocation for ItemId in StmtKind)
 - #58530 (Monomorphize less code in fs::{read|write})
 - #58534 (Mention capping forbid lints)
 - #58536 (Remove UB in pointer tests)
 - #58538 (Add missing fmt structs examples)
 - #58539 (Add alias methods to PathBuf for underlying OsString (#58234))
 - #58544 (Fix doc for rustc "-g" flag)
 - #58545 (Add regression test for a specialization-related ICE (#39448))
 - #58546 (librustc_codegen_llvm => 2018)
 - #58551 (Explain a panic in test case net::tcp::tests::double_bind)
 - #58553 (Use more impl header lifetime elision)
 - #58562 (Fix style nits)
 - #58565 (Fix typo in std::future::Future docs)
 - #58568 (Fix a transposition in driver.rs.)
 - #58569 (Reduce Some Code Repetitions like `(n << amt) >> amt`)
 - #58576 (Stabilize iter::successors and iter::from_fn)

src/doc/rustc/src/command-line-arguments.md

@@ -42,11 +42,11 @@ This flag prints out various information about the compiler.
 
 ## `-g`: include debug information
 
-A synonym for `-C debug-level=2`.
+A synonym for `-C debuginfo=2`, for more see [here](codegen-options/index.html#debuginfo).
 
 ## `-O`: optimize your code
 
-A synonym for `-C opt-level=2`.
+A synonym for `-C opt-level=2`, for more see [here](codegen-options/index.html#opt-level).
 
 ## `-o`: filename of the output
 

src/doc/rustc/src/lints/levels.md

@@ -90,7 +90,9 @@ This lint level gives you that.
 'forbid' is a special lint level that's stronger than 'deny'. It's the same
 as 'deny' in that a lint at this level will produce an error, but unlike the
 'deny' level, the 'forbid' level can not be overridden to be anything lower
-than an error.
+than an error.  However, lint levels may still be capped with `--cap-lints`
+(see below) so `rustc --cap-lints warn` will make lints set to 'forbid' just
+warn.
 
 ## Configuring warning levels
 

src/doc/rustdoc/src/documentation-tests.md

@@ -236,6 +236,23 @@ appears to the reader as the initial idea but works with doc tests:
 /// ```
 ```
 
+As of version 1.34.0, one can also omit the `fn main()`, but you will have to
+disambiguate the error type:
+
+```ignore
+/// ```
+/// use std::io;
+/// let mut input = String::new();
+/// io::stdin().read_line(&mut input)?;
+/// # Ok::<(), io:Error>(())
+/// ```
+```
+
+This is an unfortunate consequence of the `?` operator adding an implicit
+conversion, so type inference fails because the type is not unique. Please note
+that you must write the `(())` in one sequence without intermediate whitespace
+so that rustdoc understands you want an implicit `Result`-returning function.
+
 ## Documenting macros
 
 Here’s an example of documenting a macro:

src/liballoc/borrow.rs

@@ -182,8 +182,8 @@ pub enum Cow<'a, B: ?Sized + 'a>
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized + ToOwned> Clone for Cow<'a, B> {
-    fn clone(&self) -> Cow<'a, B> {
+impl<B: ?Sized + ToOwned> Clone for Cow<'_, B> {
+    fn clone(&self) -> Self {
         match *self {
             Borrowed(b) => Borrowed(b),
             Owned(ref o) => {
@@ -193,7 +193,7 @@ impl<'a, B: ?Sized + ToOwned> Clone for Cow<'a, B> {
         }
     }
 
-    fn clone_from(&mut self, source: &Cow<'a, B>) {
+    fn clone_from(&mut self, source: &Self) {
         if let Owned(ref mut dest) = *self {
             if let Owned(ref o) = *source {
                 o.borrow().clone_into(dest);
@@ -296,11 +296,11 @@ impl<B: ?Sized + ToOwned> Deref for Cow<'_, B> {
 impl<B: ?Sized> Eq for Cow<'_, B> where B: Eq + ToOwned {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Ord for Cow<'a, B>
+impl<B: ?Sized> Ord for Cow<'_, B>
     where B: Ord + ToOwned
 {
     #[inline]
-    fn cmp(&self, other: &Cow<'a, B>) -> Ordering {
+    fn cmp(&self, other: &Self) -> Ordering {
         Ord::cmp(&**self, &**other)
     }
 }
@@ -353,18 +353,18 @@ impl<B: ?Sized> fmt::Display for Cow<'_, B>
 }
 
 #[stable(feature = "default", since = "1.11.0")]
-impl<'a, B: ?Sized> Default for Cow<'a, B>
+impl<B: ?Sized> Default for Cow<'_, B>
     where B: ToOwned,
           <B as ToOwned>::Owned: Default
 {
     /// Creates an owned Cow<'a, B> with the default value for the contained owned value.
-    fn default() -> Cow<'a, B> {
+    fn default() -> Self {
         Owned(<B as ToOwned>::Owned::default())
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, B: ?Sized> Hash for Cow<'a, B>
+impl<B: ?Sized> Hash for Cow<'_, B>
     where B: Hash + ToOwned
 {
     #[inline]

src/liballoc/collections/binary_heap.rs

@@ -947,8 +947,8 @@ impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }

src/liballoc/collections/btree/map.rs

@@ -1218,8 +1218,8 @@ impl<K, V> ExactSizeIterator for Iter<'_, K, V> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
+impl<K, V> Clone for Iter<'_, K, V> {
+    fn clone(&self) -> Self {
         Iter {
             range: self.range.clone(),
             length: self.length,
@@ -1441,8 +1441,8 @@ impl<K, V> ExactSizeIterator for Keys<'_, K, V> {
 impl<K, V> FusedIterator for Keys<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Keys<'a, K, V> {
-    fn clone(&self) -> Keys<'a, K, V> {
+impl<K, V> Clone for Keys<'_, K, V> {
+    fn clone(&self) -> Self {
         Keys { inner: self.inner.clone() }
     }
 }
@@ -1478,8 +1478,8 @@ impl<K, V> ExactSizeIterator for Values<'_, K, V> {
 impl<K, V> FusedIterator for Values<'_, K, V> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Clone for Values<'a, K, V> {
-    fn clone(&self) -> Values<'a, K, V> {
+impl<K, V> Clone for Values<'_, K, V> {
+    fn clone(&self) -> Self {
         Values { inner: self.inner.clone() }
     }
 }
@@ -1606,8 +1606,8 @@ impl<'a, K, V> Range<'a, K, V> {
 impl<K, V> FusedIterator for Range<'_, K, V> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
-impl<'a, K, V> Clone for Range<'a, K, V> {
-    fn clone(&self) -> Range<'a, K, V> {
+impl<K, V> Clone for Range<'_, K, V> {
+    fn clone(&self) -> Self {
         Range {
             front: self.front,
             back: self.back,

src/liballoc/collections/btree/set.rs

@@ -907,8 +907,8 @@ impl<T: Debug> Debug for BTreeSet<T> {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter { iter: self.iter.clone() }
     }
 }
@@ -963,8 +963,8 @@ impl<T> ExactSizeIterator for IntoIter<T> {
 impl<T> FusedIterator for IntoIter<T> {}
 
 #[stable(feature = "btree_range", since = "1.17.0")]
-impl<'a, T> Clone for Range<'a, T> {
-    fn clone(&self) -> Range<'a, T> {
+impl<T> Clone for Range<'_, T> {
+    fn clone(&self) -> Self {
         Range { iter: self.iter.clone() }
     }
 }
@@ -998,8 +998,8 @@ fn cmp_opt<T: Ord>(x: Option<&T>, y: Option<&T>, short: Ordering, long: Ordering
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Difference<'a, T> {
-    fn clone(&self) -> Difference<'a, T> {
+impl<T> Clone for Difference<'_, T> {
+    fn clone(&self) -> Self {
         Difference {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1036,8 +1036,8 @@ impl<'a, T: Ord> Iterator for Difference<'a, T> {
 impl<T: Ord> FusedIterator for Difference<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for SymmetricDifference<'a, T> {
-    fn clone(&self) -> SymmetricDifference<'a, T> {
+impl<T> Clone for SymmetricDifference<'_, T> {
+    fn clone(&self) -> Self {
         SymmetricDifference {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1070,8 +1070,8 @@ impl<'a, T: Ord> Iterator for SymmetricDifference<'a, T> {
 impl<T: Ord> FusedIterator for SymmetricDifference<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Intersection<'a, T> {
-    fn clone(&self) -> Intersection<'a, T> {
+impl<T> Clone for Intersection<'_, T> {
+    fn clone(&self) -> Self {
         Intersection {
             a: self.a.clone(),
             b: self.b.clone(),
@@ -1108,8 +1108,8 @@ impl<'a, T: Ord> Iterator for Intersection<'a, T> {
 impl<T: Ord> FusedIterator for Intersection<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Union<'a, T> {
-    fn clone(&self) -> Union<'a, T> {
+impl<T> Clone for Union<'_, T> {
+    fn clone(&self) -> Self {
         Union {
             a: self.a.clone(),
             b: self.b.clone(),

src/liballoc/collections/linked_list.rs

@@ -1200,16 +1200,16 @@ unsafe impl<T: Send> Send for LinkedList<T> {}
 unsafe impl<T: Sync> Sync for LinkedList<T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Send for Iter<'a, T> {}
+unsafe impl<T: Sync> Send for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Sync for Iter<'a, T> {}
+unsafe impl<T: Sync> Sync for Iter<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Send> Send for IterMut<'a, T> {}
+unsafe impl<T: Send> Send for IterMut<'_, T> {}
 
 #[stable(feature = "rust1", since = "1.0.0")]
-unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
+unsafe impl<T: Sync> Sync for IterMut<'_, T> {}
 
 #[cfg(test)]
 mod tests {

src/liballoc/collections/vec_deque.rs

@@ -2132,8 +2132,8 @@ impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
 
 // FIXME(#26925) Remove in favor of `#[derive(Clone)]`
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T> Clone for Iter<'a, T> {
-    fn clone(&self) -> Iter<'a, T> {
+impl<T> Clone for Iter<'_, T> {
+    fn clone(&self) -> Self {
         Iter {
             ring: self.ring,
             tail: self.tail,
@@ -2225,7 +2225,7 @@ pub struct IterMut<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: fmt::Debug> fmt::Debug for IterMut<'_, T> {
+impl<T: fmt::Debug> fmt::Debug for IterMut<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let (front, back) = RingSlices::ring_slices(&*self.ring, self.head, self.tail);
         f.debug_tuple("IterMut")

src/liballoc/vec.rs

@@ -2455,7 +2455,7 @@ pub struct Drain<'a, T: 'a> {
 }
 
 #[stable(feature = "collection_debug", since = "1.17.0")]
-impl<'a, T: 'a + fmt::Debug> fmt::Debug for Drain<'a, T> {
+impl<T: fmt::Debug> fmt::Debug for Drain<'_, T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_tuple("Drain")
          .field(&self.iter.as_slice())