rollup merge of rust-lang#23875: aturon/revise-convert-2

* Marks `#[stable]` the contents of the `std::convert` module.

* Added methods `PathBuf::as_path`, `OsString::as_os_str`,
  `String::as_str`, `Vec::{as_slice, as_mut_slice}`.

* Deprecates `OsStr::from_str` in favor of a new, stable, and more
  general `OsStr::new`.

* Adds unstable methods `OsString::from_bytes` and `OsStr::{to_bytes,
  to_cstring}` for ergonomic FFI usage.

[breaking-change]

r? @alexcrichton

src/compiletest/compiletest.rs

@@ -18,7 +18,6 @@
 #![feature(std_misc)]
 #![feature(test)]
 #![feature(path_ext)]
-#![feature(convert)]
 #![feature(str_char)]
 
 #![deny(warnings)]

src/libcollections/lib.rs

@@ -38,7 +38,6 @@
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(step_by)]
 #![feature(str_char)]
-#![feature(convert)]
 #![feature(slice_patterns)]
 #![feature(debug_builders)]
 #![cfg_attr(test, feature(rand, rustc_private, test, hash, collections))]

src/libcollections/string.rs

@@ -364,6 +364,14 @@ impl String {
         self.vec
     }
 
+    /// Extract a string slice containing the entire string.
+    #[inline]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
+    pub fn as_str(&self) -> &str {
+        self
+    }
+
     /// Pushes the given string onto this string buffer.
     ///
     /// # Examples
@@ -848,7 +856,6 @@ impl<'a, 'b> PartialEq<Cow<'a, str>> for &'b str {
 #[allow(deprecated)]
 impl Str for String {
     #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_slice(&self) -> &str {
         unsafe { mem::transmute(&*self.vec) }
     }

src/libcollections/vec.rs

@@ -425,11 +425,18 @@ impl<T> Vec<T> {
         }
     }
 
+    /// Extract a slice containing the entire vector.
+    #[inline]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
+    pub fn as_slice(&self) -> &[T] {
+        self
+    }
+
     /// Deprecated: use `&mut s[..]` instead.
     #[inline]
-    #[unstable(feature = "collections",
-               reason = "will be replaced by slice syntax")]
-    #[deprecated(since = "1.0.0", reason = "use &mut s[..] instead")]
+    #[unstable(feature = "convert",
+               reason = "waiting on RFC revision")]
     pub fn as_mut_slice(&mut self) -> &mut [T] {
         &mut self[..]
     }
@@ -1642,13 +1649,6 @@ impl<T> AsRef<Vec<T>> for Vec<T> {
     }
 }
 
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T> Into<Vec<T>> for Vec<T> {
-    fn into(self) -> Vec<T> {
-        self
-    }
-}
-
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsRef<[T]> for Vec<T> {
     fn as_ref(&self) -> &[T] {

src/libcore/convert.rs

@@ -14,55 +14,57 @@
 //! conversions from one type to another. They follow the standard
 //! Rust conventions of `as`/`to`/`into`/`from`.
 
-#![unstable(feature = "convert",
-            reason = "recently added, experimental traits")]
+#![stable(feature = "rust1", since = "1.0.0")]
 
 use marker::Sized;
 
 /// A cheap, reference-to-reference conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRef<T: ?Sized> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_ref(&self) -> &T;
 }
 
 /// A cheap, mutable reference-to-mutable reference conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsMut<T: ?Sized> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn as_mut(&mut self) -> &mut T;
 }
 
 /// A conversion that consumes `self`, which may or may not be
 /// expensive.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait Into<T>: Sized {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn into(self) -> T;
 }
 
 /// Construct `Self` via a conversion.
+#[stable(feature = "rust1", since = "1.0.0")]
 pub trait From<T> {
     /// Perform the conversion.
+    #[stable(feature = "rust1", since = "1.0.0")]
     fn from(T) -> Self;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // GENERIC IMPLS
 ////////////////////////////////////////////////////////////////////////////////
 
-// As implies Into
-impl<'a, T: ?Sized, U: ?Sized> Into<&'a U> for &'a T where T: AsRef<U> {
-    fn into(self) -> &'a U {
-        self.as_ref()
-    }
-}
-
 // As lifts over &
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a T where T: AsRef<U> {
     fn as_ref(&self) -> &U {
         <T as AsRef<U>>::as_ref(*self)
     }
 }
 
 // As lifts over &mut
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a mut T where T: AsRef<U> {
     fn as_ref(&self) -> &U {
         <T as AsRef<U>>::as_ref(*self)
@@ -77,14 +79,8 @@ impl<'a, T: ?Sized, U: ?Sized> AsRef<U> for &'a mut T where T: AsRef<U> {
 //     }
 // }
 
-// AsMut implies Into
-impl<'a, T: ?Sized, U: ?Sized> Into<&'a mut U> for &'a mut T where T: AsMut<U> {
-    fn into(self) -> &'a mut U {
-        (*self).as_mut()
-    }
-}
-
 // AsMut lifts over &mut
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<'a, T: ?Sized, U: ?Sized> AsMut<U> for &'a mut T where T: AsMut<U> {
     fn as_mut(&mut self) -> &mut U {
         (*self).as_mut()
@@ -100,28 +96,38 @@ impl<'a, T: ?Sized, U: ?Sized> AsMut<U> for &'a mut T where T: AsMut<U> {
 // }
 
 // From implies Into
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T, U> Into<U> for T where U: From<T> {
     fn into(self) -> U {
         U::from(self)
     }
 }
 
+// From (and thus Into) is reflexive
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> From<T> for T {
+    fn from(t: T) -> T { t }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // CONCRETE IMPLS
 ////////////////////////////////////////////////////////////////////////////////
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsRef<[T]> for [T] {
     fn as_ref(&self) -> &[T] {
         self
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl<T> AsMut<[T]> for [T] {
     fn as_mut(&mut self) -> &mut [T] {
         self
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
 impl AsRef<str> for str {
     fn as_ref(&self) -> &str {
         self

src/librustc/lib.rs

@@ -41,7 +41,6 @@
 #![feature(path_ext)]
 #![feature(str_words)]
 #![feature(str_char)]
-#![feature(convert)]
 #![feature(into_cow)]
 #![feature(slice_patterns)]
 #![cfg_attr(test, feature(test))]

src/librustc_back/lib.rs

@@ -46,7 +46,6 @@
 #![feature(path_ext)]
 #![feature(std_misc)]
 #![feature(step_by)]
-#![feature(convert)]
 #![cfg_attr(test, feature(test, rand))]
 
 extern crate syntax;

src/librustc_driver/lib.rs

@@ -38,7 +38,6 @@
 #![feature(io)]
 #![feature(set_stdio)]
 #![feature(unicode)]
-#![feature(convert)]
 
 extern crate arena;
 extern crate flate;

src/librustc_trans/lib.rs

@@ -39,7 +39,6 @@
 #![feature(unicode)]
 #![feature(path_ext)]
 #![feature(fs)]
-#![feature(convert)]
 #![feature(path_relative_from)]
 
 #![allow(trivial_casts)]

src/librustdoc/lib.rs

@@ -36,7 +36,6 @@
 #![feature(file_path)]
 #![feature(path_ext)]
 #![feature(path_relative_from)]
-#![feature(convert)]
 #![feature(slice_patterns)]
 
 extern crate arena;

src/libserialize/lib.rs

@@ -36,7 +36,6 @@ Core encoding and decoding interfaces.
 #![feature(std_misc)]
 #![feature(unicode)]
 #![feature(str_char)]
-#![feature(convert)]
 #![cfg_attr(test, feature(test, old_io))]
 
 // test harness access

src/libstd/dynamic_lib.rs

@@ -190,7 +190,6 @@ mod dl {
     use ffi::{CStr, OsStr};
     use str;
     use libc;
-    use os::unix::prelude::*;
     use ptr;
 
     pub fn open(filename: Option<&OsStr>) -> Result<*mut u8, String> {

src/libstd/env.rs

@@ -340,7 +340,6 @@ pub struct JoinPathsError {
 /// # Examples
 ///
 /// ```
-/// # #![feature(convert)]
 /// use std::env;
 /// use std::path::PathBuf;
 ///