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

2 files changed, 0 insertions, 2 deletions

diff --git a/src/liballoc/arc.rs b/src/liballoc/arc.rs
index 0cfdcd2413f..93af336ce0a 100644
--- a/src/liballoc/arc.rs
+++ b/src/liballoc/arc.rs
@@ -77,7 +77,6 @@ use core::atomic;
 use core::atomic::Ordering::{Relaxed, Release, Acquire, SeqCst};
 use core::fmt;
 use core::cmp::Ordering;
-use core::default::Default;
 use core::mem::{min_align_of, size_of};
 use core::mem;
 use core::nonzero::NonZero;
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 4468e425a85..e293a024f8e 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -50,7 +50,6 @@ use core::prelude::*;
 
 use core::any::Any;
 use core::cmp::Ordering;
-use core::default::Default;
 use core::fmt;
 use core::hash::{self, Hash};
 use core::mem;