Remove needless imports in libcollections.

src/libcollections/binary_heap.rs

@@ -151,7 +151,7 @@
 #![allow(missing_docs)]
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::ops::{Drop, Deref, DerefMut};
+use core::ops::{Deref, DerefMut};
 use core::iter::{FromIterator, FusedIterator};
 use core::mem::swap;
 use core::mem::size_of;

src/libcollections/borrow.rs

@@ -12,14 +12,9 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use core::clone::Clone;
-use core::cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd};
-use core::convert::AsRef;
-use core::default::Default;
+use core::cmp::Ordering;
 use core::hash::{Hash, Hasher};
-use core::marker::Sized;
 use core::ops::Deref;
-use core::option::Option;
 
 use fmt;
 

src/libcollections/linked_list.rs

@@ -1159,9 +1159,6 @@ unsafe impl<'a, T: Sync> Sync for IterMut<'a, T> {}
 
 #[cfg(test)]
 mod tests {
- use std::clone::Clone;
- use std::iter::{Iterator, IntoIterator, Extend};
- use std::option::Option::{self, Some, None};
  use std::__rand::{thread_rng, Rng};
  use std::thread;
  use std::vec::Vec;
@@ -1319,7 +1316,6 @@ mod tests {
 
  #[test]
  fn test_26021() {
- use std::iter::ExactSizeIterator;
  // There was a bug in split_off that failed to null out the RHS's head's prev ptr.
  // This caused the RHS's dtor to walk up into the LHS at drop and delete all of
  // its nodes.

src/libcollections/range.rs

@@ -14,7 +14,6 @@
 
 //! Range syntax.
 
-use core::option::Option::{self, None, Some};
 use core::ops::{RangeFull, Range, RangeTo, RangeFrom};
 
 /// **RangeArgument** is implemented by Rust's built-in range types, produced

src/libcollections/vec_deque.rs

@@ -2332,9 +2332,6 @@ impl<T> From<VecDeque<T>> for Vec<T> {
 
 #[cfg(test)]
 mod tests {
- use core::iter::Iterator;
- use core::option::Option::Some;
-
  use test;
 
  use super::VecDeque;