Auto merge of #35951 - GuillaumeGomez:rollup, r=GuillaumeGomez

Rollup of 6 pull requests

- Successful merges: #35910, #35912, #35913, #35936, #35939, #35949
- Failed merges: #35395

src/doc/book/macros.md

@@ -662,7 +662,7 @@ Here are some common macros you’ll see in Rust code.
 This macro causes the current thread to panic. You can give it a message
 to panic with:
 
-```rust,no_run
+```rust,should_panic
 panic!("oh no!");
 ```
 
@@ -688,7 +688,7 @@ These two macros are used in tests. `assert!` takes a boolean. `assert_eq!`
 takes two values and checks them for equality. `true` passes, `false` `panic!`s.
 Like this:
 
-```rust,no_run
+```rust,should_panic
 // A-ok!
 
 assert!(true);

src/libcore/default.rs

@@ -38,7 +38,6 @@ use marker::Sized;
 ///     bar: f32,
 /// }
 ///
-///
 /// fn main() {
 ///     let options: SomeOptions = Default::default();
 /// }

src/libcore/ops.rs

@@ -421,25 +421,68 @@ mul_impl! { usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 }
 ///
 /// # Examples
 ///
-/// A trivial implementation of `Div`. When `Foo / Foo` happens, it ends up
-/// calling `div`, and therefore, `main` prints `Dividing!`.
+/// Implementing a `Div`idable rational number struct:
 ///
 /// ```
 /// use std::ops::Div;
 ///
-/// struct Foo;
+/// // The uniqueness of rational numbers in lowest terms is a consequence of
+/// // the fundamental theorem of arithmetic.
+/// #[derive(Eq)]
+/// #[derive(PartialEq, Debug)]
+/// struct Rational {
+///     nominator: usize,
+///     denominator: usize,
+/// }
 ///
-/// impl Div for Foo {
-///     type Output = Foo;
+/// impl Rational {
+///     fn new(nominator: usize, denominator: usize) -> Self {
+///         if denominator == 0 {
+///             panic!("Zero is an invalid denominator!");
+///         }
 ///
-///     fn div(self, _rhs: Foo) -> Foo {
-///         println!("Dividing!");
-///         self
+///         // Reduce to lowest terms by dividing by the greatest common
+///         // divisor.
+///         let gcd = gcd(nominator, denominator);
+///         Rational {
+///             nominator: nominator / gcd,
+///             denominator: denominator / gcd,
+///         }
+///     }
+/// }
+///
+/// impl Div for Rational {
+///     // The division of rational numbers is a closed operation.
+///     type Output = Self;
+///
+///     fn div(self, rhs: Self) -> Self {
+///         if rhs.nominator == 0 {
+///             panic!("Cannot divide by zero-valued `Rational`!");
+///         }
+///
+///         let nominator = self.nominator * rhs.denominator;
+///         let denominator = self.denominator * rhs.nominator;
+///         Rational::new(nominator, denominator)
+///     }
+/// }
+///
+/// // Euclid's two-thousand-year-old algorithm for finding the greatest common
+/// // divisor.
+/// fn gcd(x: usize, y: usize) -> usize {
+///     let mut x = x;
+///     let mut y = y;
+///     while y != 0 {
+///         let t = y;
+///         y = x % y;
+///         x = t;
 ///     }
+///     x
 /// }
 ///
 /// fn main() {
-///     Foo / Foo;
+///     assert_eq!(Rational::new(1, 2), Rational::new(2, 4));
+///     assert_eq!(Rational::new(1, 2) / Rational::new(3, 4),
+///                Rational::new(2, 3));
 /// }
 /// ```
 ///

src/libcore/str/mod.rs

@@ -388,8 +388,9 @@ pub fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) -> Option<
 /// Reads the last code point out of a byte iterator (assuming a
 /// UTF-8-like encoding).
 #[inline]
-fn next_code_point_reverse<'a,
-                           I: DoubleEndedIterator<Item = &'a u8>>(bytes: &mut I) -> Option<u32> {
+fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
+    where I: DoubleEndedIterator<Item = &'a u8>,
+{
     // Decode UTF-8
     let w = match bytes.next_back() {
         None => return None,

src/librustc_typeck/check/compare_method.rs

@@ -469,10 +469,11 @@ pub fn compare_impl_method<'a, 'tcx>(ccx: &CrateCtxt<'a, 'tcx>,
         // are zero. Since I don't quite know how to phrase things at
         // the moment, give a kind of vague error message.
         if trait_params.len() != impl_params.len() {
-            span_err!(ccx.tcx.sess, span, E0195,
+            struct_span_err!(ccx.tcx.sess, span, E0195,
                 "lifetime parameters or bounds on method `{}` do \
-                         not match the trait declaration",
-                         impl_m.name);
+                 not match the trait declaration",impl_m.name)
+                .span_label(span, &format!("lifetimes do not match trait"))
+                .emit();
             return false;
         }
 

src/test/compile-fail/E0195.rs

@@ -16,6 +16,7 @@ struct Foo;
 
 impl Trait for Foo {
     fn bar<'a,'b>(x: &'a str, y: &'b str) { //~ ERROR E0195
+                                            //~^ lifetimes do not match trait
     }
 }
 

src/test/compile-fail/issue-16048.rs

@@ -29,6 +29,7 @@ impl<'a> Test<'a> for Foo<'a> {
 impl<'a> NoLifetime for Foo<'a> {
     fn get<'p, T : Test<'a>>(&self) -> T {
 //~^ ERROR E0195
+//~| lifetimes do not match trait
         return *self as T;
     }
 }