Rollup of 11 pull requests

src/libcore/iter/range.rs

@@ -263,14 +263,12 @@ impl<A: Step> ops::RangeFrom<A> {
     /// # Examples
     ///
     /// ```
-    /// # #![feature(step_by)]
-    ///
-    /// for i in (0u8..).step_by(2).take(10) {
-    ///     println!("{}", i);
+    /// #![feature(step_by)]
+    /// fn main() {
+    ///     let result: Vec<_> = (0..).step_by(2).take(5).collect();
+    ///     assert_eq!(result, vec![0, 2, 4, 6, 8]);
     /// }
     /// ```
-    ///
-    /// This prints the first ten even natural integers (0 to 18).
     #[unstable(feature = "step_by", reason = "recent addition",
                issue = "27741")]
     pub fn step_by(self, by: A) -> StepBy<A, Self> {
@@ -291,8 +289,10 @@ impl<A: Step> ops::Range<A> {
     ///
     /// ```
     /// #![feature(step_by)]
-    /// let result: Vec<_> = (0..10).step_by(2).collect();
-    /// assert_eq!(result, vec![0, 2, 4, 6, 8]);
+    /// fn main() {
+    ///     let result: Vec<_> = (0..10).step_by(2).collect();
+    ///     assert_eq!(result, vec![0, 2, 4, 6, 8]);
+    /// }
     /// ```
     #[unstable(feature = "step_by", reason = "recent addition",
                issue = "27741")]
@@ -315,20 +315,8 @@ impl<A: Step> ops::RangeInclusive<A> {
     /// ```
     /// #![feature(step_by, inclusive_range_syntax)]
     ///
-    /// for i in (0...10).step_by(2) {
-    ///     println!("{}", i);
-    /// }
-    /// ```
-    ///
-    /// This prints:
-    ///
-    /// ```text
-    /// 0
-    /// 2
-    /// 4
-    /// 6
-    /// 8
-    /// 10
+    /// let result: Vec<_> = (0...10).step_by(2).collect();
+    /// assert_eq!(result, vec![0, 2, 4, 6, 8, 10]);
     /// ```
     #[unstable(feature = "step_by", reason = "recent addition",
                issue = "27741")]

src/libcore/ops.rs

@@ -282,6 +282,12 @@ macro_rules! forward_ref_binop {
 ///                Point { x: 3, y: 3 });
 /// }
 /// ```
+///
+/// Note that `RHS = Self` by default, but this is not mandatory. For example,
+/// [std::time::SystemTime] implements `Add<Duration>`, which permits
+/// operations of the form `SystemTime = SystemTime + Duration`.
+///
+/// [std::time::SystemTime]: ../time/struct.SystemTime.html
 #[lang = "add"]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Add<RHS=Self> {
@@ -349,6 +355,12 @@ add_impl! { usize u8 u16 u32 u64 isize i8 i16 i32 i64 f32 f64 }
 ///                Point { x: 1, y: 0 });
 /// }
 /// ```
+///
+/// Note that `RHS = Self` by default, but this is not mandatory. For example,
+/// [std::time::SystemTime] implements `Sub<Duration>`, which permits
+/// operations of the form `SystemTime = SystemTime - Duration`.
+///
+/// [std::time::SystemTime]: ../time/struct.SystemTime.html
 #[lang = "sub"]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait Sub<RHS=Self> {

src/librustc_resolve/diagnostics.rs

@@ -1270,7 +1270,42 @@ trait Foo {}
 
 impl Foo for i32 {}
 ```
-"##
+"##,
+
+E0530: r##"
+A binding shadowed something it shouldn't.
+
+Erroneous code example:
+
+```compile_fail,E0530
+static TEST: i32 = 0;
+
+let r: (i32, i32) = (0, 0);
+match r {
+    TEST => {} // error: match bindings cannot shadow statics
+}
+```
+
+To fix this error, just change the binding's name in order to avoid shadowing
+one of the following:
+
+* struct name
+* struct/enum variant
+* static
+* const
+* associated const
+
+Fixed example:
+
+```
+static TEST: i32 = 0;
+
+let r: (i32, i32) = (0, 0);
+match r {
+    something => {} // ok!
+}
+```
+"##,
 
 }
 
@@ -1289,7 +1324,6 @@ register_diagnostics! {
 //  E0419, merged into 531
 //  E0420, merged into 532
 //  E0421, merged into 531
-    E0530, // X bindings cannot shadow Ys
     E0531, // unresolved pattern path kind `name`
     E0532, // expected pattern path kind, found another pattern path kind
 //  E0427, merged into 530

src/librustc_typeck/check/method/suggest.rs

@@ -242,6 +242,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             MethodError::Ambiguity(sources) => {
                 let mut err = struct_span_err!(self.sess(), span, E0034,
                                                "multiple applicable items in scope");
+                err.span_label(span, &format!("multiple `{}` found", item_name));
 
                 report_candidates(&mut err, sources);
                 err.emit();

src/librustc_typeck/check/mod.rs

@@ -903,14 +903,18 @@ fn report_forbidden_specialization<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 {
     let mut err = struct_span_err!(
         tcx.sess, impl_item.span, E0520,
-        "item `{}` is provided by an `impl` that specializes \
-         another, but the item in the parent `impl` is not \
-         marked `default` and so it cannot be specialized.",
+        "`{}` specializes an item from a parent `impl`, but \
+         neither that item nor the `impl` are marked `default`",
         impl_item.name);
+    err.span_label(impl_item.span, &format!("cannot specialize default item `{}`",
+                                            impl_item.name));
 
     match tcx.span_of_impl(parent_impl) {
         Ok(span) => {
-            err.span_note(span, "parent implementation is here:");
+            err.span_label(span, &"parent `impl` is here");
+            err.note(&format!("to specialize, either the parent `impl` or `{}` \
+                               in the parent `impl` must be marked `default`",
+                              impl_item.name));
         }
         Err(cname) => {
             err.note(&format!("parent implementation is in crate `{}`", cname));

src/libstd/net/tcp.rs

@@ -45,7 +45,6 @@ pub struct TcpStream(net_imp::TcpStream);
 ///
 /// ```no_run
 /// use std::net::{TcpListener, TcpStream};
-/// use std::thread;
 ///
 /// let listener = TcpListener::bind("127.0.0.1:80").unwrap();
 ///
@@ -57,17 +56,11 @@ pub struct TcpStream(net_imp::TcpStream);
 /// for stream in listener.incoming() {
 ///     match stream {
 ///         Ok(stream) => {
-///             thread::spawn(move|| {
-///                 // connection succeeded
-///                 handle_client(stream)
-///             });
+///             handle_client(stream);
 ///         }
 ///         Err(e) => { /* connection failed */ }
 ///     }
 /// }
-///
-/// // close the socket server
-/// drop(listener);
 /// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct TcpListener(net_imp::TcpListener);

src/libstd/path.rs

@@ -639,6 +639,25 @@ pub struct Iter<'a> {
     inner: Components<'a>,
 }
 
+#[stable(feature = "path_components_debug", since = "1.13.0")]
+impl<'a> fmt::Debug for Components<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        struct DebugHelper<'a>(&'a Path);
+
+        impl<'a> fmt::Debug for DebugHelper<'a> {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.debug_list()
+                    .entries(self.0.components())
+                    .finish()
+            }
+        }
+
+        f.debug_tuple("Components")
+            .field(&DebugHelper(self.as_path()))
+            .finish()
+    }
+}
+
 impl<'a> Components<'a> {
     // how long is the prefix, if any?
     #[inline]
@@ -818,6 +837,25 @@ impl<'a> AsRef<OsStr> for Components<'a> {
     }
 }
 
+#[stable(feature = "path_iter_debug", since = "1.13.0")]
+impl<'a> fmt::Debug for Iter<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        struct DebugHelper<'a>(&'a Path);
+
+        impl<'a> fmt::Debug for DebugHelper<'a> {
+            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+                f.debug_list()
+                    .entries(self.0.iter())
+                    .finish()
+            }
+        }
+
+        f.debug_tuple("Iter")
+            .field(&DebugHelper(self.as_path()))
+            .finish()
+    }
+}
+
 impl<'a> Iter<'a> {
     /// Extracts a slice corresponding to the portion of the path remaining for iteration.
     #[stable(feature = "rust1", since = "1.0.0")]
@@ -3483,4 +3521,46 @@ mod tests {
                 );
         }
     }
+
+    #[test]
+    fn test_components_debug() {
+        let path = Path::new("/tmp");
+
+        let mut components = path.components();
+
+        let expected = "Components([RootDir, Normal(\"tmp\")])";
+        let actual = format!("{:?}", components);
+        assert_eq!(expected, actual);
+
+        let _ = components.next().unwrap();
+        let expected = "Components([Normal(\"tmp\")])";
+        let actual = format!("{:?}", components);
+        assert_eq!(expected, actual);
+
+        let _ = components.next().unwrap();
+        let expected = "Components([])";
+        let actual = format!("{:?}", components);
+        assert_eq!(expected, actual);
+    }
+
+    #[test]
+    fn test_iter_debug() {
+        let path = Path::new("/tmp");
+
+        let mut iter = path.iter();
+
+        let expected = "Iter([\"/\", \"tmp\"])";
+        let actual = format!("{:?}", iter);
+        assert_eq!(expected, actual);
+
+        let _ = iter.next().unwrap();
+        let expected = "Iter([\"tmp\"])";
+        let actual = format!("{:?}", iter);
+        assert_eq!(expected, actual);
+
+        let _ = iter.next().unwrap();
+        let expected = "Iter([])";
+        let actual = format!("{:?}", iter);
+        assert_eq!(expected, actual);
+    }
 }

src/test/compile-fail/E0034.rs

@@ -18,9 +18,17 @@ trait Trait2 {
     fn foo();
 }
 
-impl Trait1 for Test { fn foo() {} }
-impl Trait2 for Test { fn foo() {} }
+impl Trait1 for Test {
+    fn foo() {}
+    //~^ NOTE candidate #1 is defined in an impl of the trait `Trait1` for the type `Test`
+}
+
+impl Trait2 for Test {
+    fn foo() {}
+    //~^ NOTE candidate #2 is defined in an impl of the trait `Trait2` for the type `Test`
+}
 
 fn main() {
-    Test::foo() //~ ERROR E0034
+    Test::foo() //~ ERROR multiple applicable items in scope
+    //~| NOTE multiple `foo` found
 }

src/test/compile-fail/E0520.rs

@@ -19,11 +19,15 @@ impl<T> SpaceLlama for T {
 }
 
 impl<T: Clone> SpaceLlama for T {
+//~^ NOTE parent `impl` is here
     fn fly(&self) {}
 }
 
 impl SpaceLlama for i32 {
-    default fn fly(&self) {} //~ ERROR E0520
+    default fn fly(&self) {}
+    //~^ ERROR E0520
+    //~| NOTE cannot specialize default item `fly`
+    //~| NOTE either the parent `impl` or `fly` in the parent `impl` must be marked `default`
 }
 
 fn main() {

src/test/compile-fail/E0528.rs

@@ -0,0 +1,19 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(slice_patterns)]
+
+fn main() {
+    let r = &[1, 2];
+    match r {
+        &[a, b, c, rest..] => { //~ ERROR E0528
+        }
+    }
+}

src/test/compile-fail/E0529.rs

@@ -0,0 +1,19 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(slice_patterns)]
+
+fn main() {
+    let r: f32 = 1.0;
+    match r {
+        [a, b] => { //~ ERROR E0529
+        }
+    }
+}

src/test/compile-fail/E0530.rs

@@ -0,0 +1,18 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {
+    static TEST: i32 = 0;
+
+    let r: (i32, i32) = (0, 0);
+    match r {
+        TEST => {} //~ ERROR E0530
+    }
+}