std: Add Default/IntoIterator/ToOwned to the prelude

This is an implementation of [RFC 1030][rfc] which adds these traits to the
prelude and additionally removes all inherent `into_iter` methods on collections
in favor of the trait implementation (which is now accessible by default).

[rfc]: https://github.com/rust-lang/rfcs/pull/1030

This is technically a breaking change due to the prelude additions and removal
of inherent methods, but it is expected that essentially no code breaks in
practice.

[breaking-change]
Closes #24538

5 files changed, 50 insertions, 43 deletions

diff --git a/src/libcore/hash/mod.rs b/src/libcore/hash/mod.rs
index 553e0c0dfe6..e848a44e01c 100644
--- a/src/libcore/hash/mod.rs
+++ b/src/libcore/hash/mod.rs
@@ -62,7 +62,6 @@
 
 use prelude::*;
 
-use default::Default;
 use mem;
 
 pub use self::sip::SipHasher;
diff --git a/src/libcore/hash/sip.rs b/src/libcore/hash/sip.rs
index 6820a7025fc..0bff9b0ba42 100644
--- a/src/libcore/hash/sip.rs
+++ b/src/libcore/hash/sip.rs
@@ -15,7 +15,6 @@
 #![allow(deprecated)] // until the next snapshot for inherent wrapping ops
 
 use prelude::*;
-use default::Default;
 use super::Hasher;
 
 /// An implementation of SipHash 2-4.
diff --git a/src/libcore/option.rs b/src/libcore/option.rs
index 4c784a579da..d1bc24bd9ba 100644
--- a/src/libcore/option.rs
+++ b/src/libcore/option.rs
@@ -551,25 +551,6 @@ impl<T> Option<T> {
         IterMut { inner: Item { opt: self.as_mut() } }
     }
 
-    /// Returns a consuming iterator over the possibly contained value.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let x = Some("string");
-    /// let v: Vec<&str> = x.into_iter().collect();
-    /// assert_eq!(v, ["string"]);
-    ///
-    /// let x = None;
-    /// let v: Vec<&str> = x.into_iter().collect();
-    /// assert!(v.is_empty());
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn into_iter(self) -> IntoIter<T> {
-        IntoIter { inner: Item { opt: self } }
-    }
-
     /////////////////////////////////////////////////////////////////////////
     // Boolean operations on the values, eager and lazy
     /////////////////////////////////////////////////////////////////////////
@@ -770,6 +751,30 @@ impl<T> Default for Option<T> {
     fn default() -> Option<T> { None }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> IntoIterator for Option<T> {
+    type Item = T;
+    type IntoIter = IntoIter<T>;
+
+    /// Returns a consuming iterator over the possibly contained value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = Some("string");
+    /// let v: Vec<&str> = x.into_iter().collect();
+    /// assert_eq!(v, ["string"]);
+    ///
+    /// let x = None;
+    /// let v: Vec<&str> = x.into_iter().collect();
+    /// assert!(v.is_empty());
+    /// ```
+    #[inline]
+    fn into_iter(self) -> IntoIter<T> {
+        IntoIter { inner: Item { opt: self } }
+    }
+}
+
 /////////////////////////////////////////////////////////////////////////////
 // The Option Iterators
 /////////////////////////////////////////////////////////////////////////////
diff --git a/src/libcore/prelude.rs b/src/libcore/prelude.rs
index e60bc494081..a4d529ad47d 100644
--- a/src/libcore/prelude.rs
+++ b/src/libcore/prelude.rs
@@ -37,11 +37,10 @@ pub use char::CharExt;
 pub use clone::Clone;
 pub use cmp::{PartialEq, PartialOrd, Eq, Ord};
 pub use convert::{AsRef, AsMut, Into, From};
+pub use default::Default;
+pub use iter::IntoIterator;
 pub use iter::{Iterator, DoubleEndedIterator, Extend, ExactSizeIterator};
 pub use option::Option::{self, Some, None};
 pub use result::Result::{self, Ok, Err};
 pub use slice::SliceExt;
 pub use str::StrExt;
-
-#[allow(deprecated)] pub use slice::AsSlice;
-#[allow(deprecated)] pub use str::Str;
diff --git a/src/libcore/result.rs b/src/libcore/result.rs
index 26bc653b26f..3ffff8de892 100644
--- a/src/libcore/result.rs
+++ b/src/libcore/result.rs
@@ -547,25 +547,6 @@ impl<T, E> Result<T, E> {
         IterMut { inner: self.as_mut().ok() }
     }
 
-    /// Returns a consuming iterator over the possibly contained value.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// let x: Result<u32, &str> = Ok(5);
-    /// let v: Vec<u32> = x.into_iter().collect();
-    /// assert_eq!(v, [5]);
-    ///
-    /// let x: Result<u32, &str> = Err("nothing!");
-    /// let v: Vec<u32> = x.into_iter().collect();
-    /// assert_eq!(v, []);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn into_iter(self) -> IntoIter<T> {
-        IntoIter { inner: self.ok() }
-    }
-
     ////////////////////////////////////////////////////////////////////////
     // Boolean operations on the values, eager and lazy
     /////////////////////////////////////////////////////////////////////////
@@ -807,6 +788,30 @@ impl<T, E> AsSlice<T> for Result<T, E> {
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, E> IntoIterator for Result<T, E> {
+    type Item = T;
+    type IntoIter = IntoIter<T>;
+
+    /// Returns a consuming iterator over the possibly contained value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x: Result<u32, &str> = Ok(5);
+    /// let v: Vec<u32> = x.into_iter().collect();
+    /// assert_eq!(v, [5]);
+    ///
+    /// let x: Result<u32, &str> = Err("nothing!");
+    /// let v: Vec<u32> = x.into_iter().collect();
+    /// assert_eq!(v, []);
+    /// ```
+    #[inline]
+    fn into_iter(self) -> IntoIter<T> {
+        IntoIter { inner: self.ok() }
+    }
+}
+
 /////////////////////////////////////////////////////////////////////////////
 // The Result Iterators
 /////////////////////////////////////////////////////////////////////////////