Auto merge of #29778 - Manishearth:rollup, r=Manishearth

- Successful merges: #29677, #29772, #29775, #29777
- Failed merges:

6 files changed, 113 insertions, 56 deletions

diff --git a/src/libcore/macros.rs b/src/libcore/macros.rs
index 5b5f59d5ddb..579232e5a5d 100644
--- a/src/libcore/macros.rs
+++ b/src/libcore/macros.rs
@@ -308,27 +308,27 @@ macro_rules! unreachable {
 ///
 /// ```
 /// # trait Foo {
-/// #     fn foo(&self);
 /// #     fn bar(&self);
+/// #     fn baz(&self);
 /// # }
 /// struct MyStruct;
 ///
 /// impl Foo for MyStruct {
-///     fn foo(&self) {
+///     fn bar(&self) {
 ///         // implementation goes here
 ///     }
 ///
-///     fn bar(&self) {
-///         // let's not worry about implementing bar() for now
+///     fn baz(&self) {
+///         // let's not worry about implementing baz() for now
 ///         unimplemented!();
 ///     }
 /// }
 ///
 /// fn main() {
 ///     let s = MyStruct;
-///     s.foo();
+///     s.bar();
 ///
-///     // we aren't even using bar() yet, so this is fine.
+///     // we aren't even using baz() yet, so this is fine.
 /// }
 /// ```
 #[macro_export]
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index e9a0efe76cb..80062b371a3 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -153,7 +153,7 @@ pub enum ResolutionError<'a> {
     /// error E0413: declaration shadows an enum variant or unit-like struct in scope
     DeclarationShadowsEnumVariantOrUnitLikeStruct(Name),
     /// error E0414: only irrefutable patterns allowed here
-    OnlyIrrefutablePatternsAllowedHere,
+    OnlyIrrefutablePatternsAllowedHere(DefId, Name),
     /// error E0415: identifier is bound more than once in this parameter list
     IdentifierBoundMoreThanOnceInParameterList(&'a str),
     /// error E0416: identifier is bound more than once in the same pattern
@@ -283,8 +283,19 @@ fn resolve_error<'b, 'a:'b, 'tcx:'a>(resolver: &'b Resolver<'a, 'tcx>, span: syn
                           scope",
                          name);
         },
-        ResolutionError::OnlyIrrefutablePatternsAllowedHere => {
+        ResolutionError::OnlyIrrefutablePatternsAllowedHere(did, name) => {
             span_err!(resolver.session, span, E0414, "only irrefutable patterns allowed here");
+            resolver.session.span_note(span, "there already is a constant in scope \
+                                               sharing the same name as this pattern");
+            if let Some(sp) = resolver.ast_map.span_if_local(did) {
+                resolver.session.span_note(sp, "constant defined here");
+            }
+            if let Some(directive) = resolver.current_module
+                                             .import_resolutions
+                                             .borrow().get(&name) {
+                let item = resolver.ast_map.expect_item(directive.value_id);
+                resolver.session.span_note(item.span, "constant imported here");
+            }
         },
         ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
             span_err!(resolver.session, span, E0415,
@@ -632,7 +643,7 @@ enum NameSearchType {
 #[derive(Copy, Clone)]
 enum BareIdentifierPatternResolution {
     FoundStructOrEnumVariant(Def, LastPrivate),
-    FoundConst(Def, LastPrivate),
+    FoundConst(Def, LastPrivate, Name),
     BareIdentifierPatternUnresolved
 }
 
@@ -2685,7 +2696,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                     renamed)
                             );
                         }
-                        FoundConst(def, lp) if const_ok => {
+                        FoundConst(def, lp, _) if const_ok => {
                             debug!("(resolving pattern) resolving `{}` to \
                                     constant",
                                    renamed);
@@ -2700,11 +2711,12 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                 depth: 0
                             });
                         }
-                        FoundConst(..) => {
+                        FoundConst(def, _, name) => {
                             resolve_error(
                                 self,
                                 pattern.span,
-                                ResolutionError::OnlyIrrefutablePatternsAllowedHere
+                                ResolutionError::OnlyIrrefutablePatternsAllowedHere(def.def_id(),
+                                                                                    name)
                             );
                         }
                         BareIdentifierPatternUnresolved => {
@@ -2929,7 +2941,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                                 return FoundStructOrEnumVariant(def, LastMod(AllPublic));
                             }
                             def @ DefConst(..) | def @ DefAssociatedConst(..) => {
-                                return FoundConst(def, LastMod(AllPublic));
+                                return FoundConst(def, LastMod(AllPublic), name);
                             }
                             DefStatic(..) => {
                                 resolve_error(self,
diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 4f39ed43b44..2d7178bd55c 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -2677,6 +2677,28 @@ defined. For more information see the [opt-in builtin traits RFC](https://github
 .com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md).
 "##,
 
+E0321: r##"
+A cross-crate opt-out trait was implemented on something which wasn't a struct
+or enum type. Erroneous code example:
+
+```
+#![feature(optin_builtin_traits)]
+
+struct Foo;
+
+impl !Sync for Foo {}
+
+unsafe impl Send for &'static Foo {
+// error: cross-crate traits with a default impl, like `core::marker::Send`,
+//        can only be implemented for a struct/enum type, not
+//        `&'static Foo`
+```
+
+Only structs and enums are permitted to impl Send, Sync, and other opt-out
+trait, and the struct or enum must be local to the current crate. So, for
+example, `unsafe impl Send for Rc<Foo>` is not allowed.
+"##,
+
 E0322: r##"
 The `Sized` trait is a special trait built-in to the compiler for types with a
 constant size known at compile-time. This trait is automatically implemented
@@ -3463,7 +3485,6 @@ register_diagnostics! {
 //  E0246, // invalid recursive type
 //  E0319, // trait impls for defaulted traits allowed just for structs/enums
     E0320, // recursive overflow during dropck
-    E0321, // extended coherence rules for defaulted traits violated
     E0328, // cannot implement Unsize explicitly
     E0374, // the trait `CoerceUnsized` may only be implemented for a coercion
            // between structures with one field being coerced, none found
diff --git a/src/libstd/ffi/c_str.rs b/src/libstd/ffi/c_str.rs
index 89427f7851b..42fd2321f01 100644
--- a/src/libstd/ffi/c_str.rs
+++ b/src/libstd/ffi/c_str.rs
@@ -21,6 +21,7 @@ use libc;
 use mem;
 use ops::Deref;
 use option::Option::{self, Some, None};
+use os::raw::c_char;
 use result::Result::{self, Ok, Err};
 use slice;
 use str::{self, Utf8Error};
@@ -36,23 +37,20 @@ use vec::Vec;
 ///
 /// A `CString` is created from either a byte slice or a byte vector. After
 /// being created, a `CString` predominately inherits all of its methods from
-/// the `Deref` implementation to `[libc::c_char]`. Note that the underlying
-/// array is represented as an array of `libc::c_char` as opposed to `u8`. A
-/// `u8` slice can be obtained with the `as_bytes` method.  Slices produced from
-/// a `CString` do *not* contain the trailing nul terminator unless otherwise
-/// specified.
+/// the `Deref` implementation to `[c_char]`. Note that the underlying array
+/// is represented as an array of `c_char` as opposed to `u8`. A `u8` slice
+/// can be obtained with the `as_bytes` method.  Slices produced from a `CString`
+/// do *not* contain the trailing nul terminator unless otherwise specified.
 ///
 /// # Examples
 ///
 /// ```no_run
-/// # #![feature(libc)]
-/// # extern crate libc;
 /// # fn main() {
 /// use std::ffi::CString;
-/// use libc;
+/// use std::os::raw::c_char;
 ///
 /// extern {
-///     fn my_printer(s: *const libc::c_char);
+///     fn my_printer(s: *const c_char);
 /// }
 ///
 /// let c_to_print = CString::new("Hello, world!").unwrap();
@@ -83,11 +81,10 @@ pub struct CString {
 /// Inspecting a foreign C string
 ///
 /// ```no_run
-/// # #![feature(libc)]
-/// extern crate libc;
 /// use std::ffi::CStr;
+/// use std::os::raw::c_char;
 ///
-/// extern { fn my_string() -> *const libc::c_char; }
+/// extern { fn my_string() -> *const c_char; }
 ///
 /// fn main() {
 ///     unsafe {
@@ -100,12 +97,11 @@ pub struct CString {
 /// Passing a Rust-originating C string
 ///
 /// ```no_run
-/// # #![feature(libc)]
-/// extern crate libc;
 /// use std::ffi::{CString, CStr};
+/// use std::os::raw::c_char;
 ///
 /// fn work(data: &CStr) {
-///     extern { fn work_with(data: *const libc::c_char); }
+///     extern { fn work_with(data: *const c_char); }
 ///
 ///     unsafe { work_with(data.as_ptr()) }
 /// }
@@ -119,11 +115,10 @@ pub struct CString {
 /// Converting a foreign C string into a Rust `String`
 ///
 /// ```no_run
-/// # #![feature(libc)]
-/// extern crate libc;
 /// use std::ffi::CStr;
+/// use std::os::raw::c_char;
 ///
-/// extern { fn my_string() -> *const libc::c_char; }
+/// extern { fn my_string() -> *const c_char; }
 ///
 /// fn my_string_safe() -> String {
 ///     unsafe {
@@ -139,10 +134,10 @@ pub struct CString {
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct CStr {
     // FIXME: this should not be represented with a DST slice but rather with
-    //        just a raw `libc::c_char` along with some form of marker to make
+    //        just a raw `c_char` along with some form of marker to make
     //        this an unsized type. Essentially `sizeof(&CStr)` should be the
     //        same as `sizeof(&c_char)` but `CStr` should be an unsized type.
-    inner: [libc::c_char]
+    inner: [c_char]
 }
 
 /// An error returned from `CString::new` to indicate that a nul byte was found
@@ -169,11 +164,10 @@ impl CString {
     /// # Examples
     ///
     /// ```no_run
-    /// # #![feature(libc)]
-    /// extern crate libc;
     /// use std::ffi::CString;
+    /// use std::os::raw::c_char;
     ///
-    /// extern { fn puts(s: *const libc::c_char); }
+    /// extern { fn puts(s: *const c_char); }
     ///
     /// fn main() {
     ///     let to_print = CString::new("Hello!").unwrap();
@@ -220,7 +214,7 @@ impl CString {
     #[unstable(feature = "cstr_memory2", reason = "recently added",
                issue = "27769")]
     #[deprecated(since = "1.4.0", reason = "renamed to from_raw")]
-    pub unsafe fn from_ptr(ptr: *const libc::c_char) -> CString {
+    pub unsafe fn from_ptr(ptr: *const c_char) -> CString {
         CString::from_raw(ptr as *mut _)
     }
 
@@ -230,7 +224,7 @@ impl CString {
     /// `into_raw`. The length of the string will be recalculated
     /// using the pointer.
     #[stable(feature = "cstr_memory", since = "1.4.0")]
-    pub unsafe fn from_raw(ptr: *mut libc::c_char) -> CString {
+    pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
         let len = libc::strlen(ptr) + 1; // Including the NUL byte
         let slice = slice::from_raw_parts(ptr, len as usize);
         CString { inner: mem::transmute(slice) }
@@ -247,7 +241,7 @@ impl CString {
     #[unstable(feature = "cstr_memory2", reason = "recently added",
                issue = "27769")]
     #[deprecated(since = "1.4.0", reason = "renamed to into_raw")]
-    pub fn into_ptr(self) -> *const libc::c_char {
+    pub fn into_ptr(self) -> *const c_char {
         self.into_raw() as *const _
     }
 
@@ -260,8 +254,8 @@ impl CString {
     ///
     /// Failure to call `from_raw` will lead to a memory leak.
     #[stable(feature = "cstr_memory", since = "1.4.0")]
-    pub fn into_raw(self) -> *mut libc::c_char {
-        Box::into_raw(self.inner) as *mut libc::c_char
+    pub fn into_raw(self) -> *mut c_char {
+        Box::into_raw(self.inner) as *mut c_char
     }
 
     /// Converts the `CString` into a `String` if it contains valid Unicode data.
@@ -426,15 +420,13 @@ impl CStr {
     /// # Examples
     ///
     /// ```no_run
-    /// # #![feature(libc)]
-    /// # extern crate libc;
     /// # fn main() {
     /// use std::ffi::CStr;
+    /// use std::os::raw::c_char;
     /// use std::str;
-    /// use libc;
     ///
     /// extern {
-    ///     fn my_string() -> *const libc::c_char;
+    ///     fn my_string() -> *const c_char;
     /// }
     ///
     /// unsafe {
@@ -445,7 +437,7 @@ impl CStr {
     /// # }
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub unsafe fn from_ptr<'a>(ptr: *const libc::c_char) -> &'a CStr {
+    pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
         let len = libc::strlen(ptr);
         mem::transmute(slice::from_raw_parts(ptr, len as usize + 1))
     }
@@ -456,7 +448,7 @@ impl CStr {
     /// to a contiguous region of memory terminated with a 0 byte to represent
     /// the end of the string.
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn as_ptr(&self) -> *const libc::c_char {
+    pub fn as_ptr(&self) -> *const c_char {
         self.inner.as_ptr()
     }
 
@@ -560,14 +552,14 @@ impl ToOwned for CStr {
 mod tests {
     use prelude::v1::*;
     use super::*;
-    use libc;
+    use os::raw::c_char;
     use borrow::Cow::{Borrowed, Owned};
     use hash::{SipHasher, Hash, Hasher};
 
     #[test]
     fn c_to_rust() {
         let data = b"123\0";
-        let ptr = data.as_ptr() as *const libc::c_char;
+        let ptr = data.as_ptr() as *const c_char;
         unsafe {
             assert_eq!(CStr::from_ptr(ptr).to_bytes(), b"123");
             assert_eq!(CStr::from_ptr(ptr).to_bytes_with_nul(), b"123\0");
@@ -616,13 +608,13 @@ mod tests {
     #[test]
     fn to_str() {
         let data = b"123\xE2\x80\xA6\0";
-        let ptr = data.as_ptr() as *const libc::c_char;
+        let ptr = data.as_ptr() as *const c_char;
         unsafe {
             assert_eq!(CStr::from_ptr(ptr).to_str(), Ok("123…"));
             assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Borrowed("123…"));
         }
         let data = b"123\xE2\0";
-        let ptr = data.as_ptr() as *const libc::c_char;
+        let ptr = data.as_ptr() as *const c_char;
         unsafe {
             assert!(CStr::from_ptr(ptr).to_str().is_err());
             assert_eq!(CStr::from_ptr(ptr).to_string_lossy(), Owned::<str>(format!("123\u{FFFD}")));
@@ -632,7 +624,7 @@ mod tests {
     #[test]
     fn to_owned() {
         let data = b"123\0";
-        let ptr = data.as_ptr() as *const libc::c_char;
+        let ptr = data.as_ptr() as *const c_char;
 
         let owned = unsafe { CStr::from_ptr(ptr).to_owned() };
         assert_eq!(owned.as_bytes_with_nul(), data);
@@ -641,7 +633,7 @@ mod tests {
     #[test]
     fn equal_hash() {
         let data = b"123\xE2\xFA\xA6\0";
-        let ptr = data.as_ptr() as *const libc::c_char;
+        let ptr = data.as_ptr() as *const c_char;
         let cstr: &'static CStr = unsafe { CStr::from_ptr(ptr) };
 
         let mut s = SipHasher::new_with_keys(0, 0);
diff --git a/src/libstd/os/raw.rs b/src/libstd/os/raw.rs
index 60069cf7bc3..17d6b2605c6 100644
--- a/src/libstd/os/raw.rs
+++ b/src/libstd/os/raw.rs
@@ -12,9 +12,13 @@
 
 #![stable(feature = "raw_os", since = "1.1.0")]
 
-#[cfg(any(target_arch = "aarch64", target_os = "android"))]
+#[cfg(any(target_os = "android",
+          all(target_os = "linux", any(target_arch = "aarch64",
+                                       target_arch = "arm"))))]
 #[stable(feature = "raw_os", since = "1.1.0")] pub type c_char = u8;
-#[cfg(not(any(target_arch = "aarch64", target_os = "android")))]
+#[cfg(not(any(target_os = "android",
+              all(target_os = "linux", any(target_arch = "aarch64",
+                                           target_arch = "arm")))))]
 #[stable(feature = "raw_os", since = "1.1.0")] pub type c_char = i8;
 #[stable(feature = "raw_os", since = "1.1.0")] pub type c_schar = i8;
 #[stable(feature = "raw_os", since = "1.1.0")] pub type c_uchar = u8;
diff --git a/src/test/compile-fail/const-pattern-irrefutable.rs b/src/test/compile-fail/const-pattern-irrefutable.rs
new file mode 100644
index 00000000000..2d345d9142b
--- /dev/null
+++ b/src/test/compile-fail/const-pattern-irrefutable.rs
@@ -0,0 +1,28 @@
+// Copyright 2015 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.
+
+mod foo {
+    const b: u8 = 2; //~ NOTE constant defined here
+    const d: u8 = 2; //~ NOTE constant defined here
+}
+
+use foo::b as c; //~ NOTE constant imported here
+use foo::d; //~ NOTE constant imported here
+
+const a: u8 = 2; //~ NOTE constant defined here
+
+fn main() {
+    let a = 4; //~ ERROR only irrefutable
+               //~^ NOTE there already is a constant in scope
+    let c = 4; //~ ERROR only irrefutable
+               //~^ NOTE there already is a constant in scope
+    let d = 4; //~ ERROR only irrefutable
+               //~^ NOTE there already is a constant in scope
+}