Rollup merge of #22584 - alexcrichton:snapshots, r=Gankro

4 files changed, 0 insertions, 3609 deletions

diff --git a/src/libstd/collections/hash/map_stage0.rs b/src/libstd/collections/hash/map_stage0.rs
deleted file mode 100644
index f9e5044c597..00000000000
--- a/src/libstd/collections/hash/map_stage0.rs
+++ /dev/null
@@ -1,2330 +0,0 @@
-// Copyright 2014-2015 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.
-//
-// ignore-lexer-test FIXME #15883
-
-use self::Entry::*;
-use self::SearchResult::*;
-use self::VacantEntryState::*;
-
-use borrow::Borrow;
-use clone::Clone;
-use cmp::{max, Eq, PartialEq};
-use default::Default;
-use fmt::{self, Debug};
-use hash::{self, Hash, SipHasher};
-use iter::{self, Iterator, ExactSizeIterator, IntoIterator, IteratorExt, FromIterator, Extend, Map};
-use marker::Sized;
-use mem::{self, replace};
-use num::{Int, UnsignedInt};
-use ops::{Deref, FnMut, Index, IndexMut};
-use option::Option::{self, Some, None};
-use rand::{self, Rng};
-use result::Result::{self, Ok, Err};
-
-use super::table::{
-    self,
-    Bucket,
-    EmptyBucket,
-    FullBucket,
-    FullBucketImm,
-    FullBucketMut,
-    RawTable,
-    SafeHash
-};
-use super::table::BucketState::{
-    Empty,
-    Full,
-};
-use super::state::HashState;
-
-const INITIAL_LOG2_CAP: usize = 5;
-#[unstable(feature = "std_misc")]
-pub const INITIAL_CAPACITY: usize = 1 << INITIAL_LOG2_CAP; // 2^5
-
-/// The default behavior of HashMap implements a load factor of 90.9%.
-/// This behavior is characterized by the following condition:
-///
-/// - if size > 0.909 * capacity: grow the map
-#[derive(Clone)]
-struct DefaultResizePolicy;
-
-impl DefaultResizePolicy {
-    fn new() -> DefaultResizePolicy {
-        DefaultResizePolicy
-    }
-
-    #[inline]
-    fn min_capacity(&self, usable_size: usize) -> usize {
-        // Here, we are rephrasing the logic by specifying the lower limit
-        // on capacity:
-        //
-        // - if `cap < size * 1.1`: grow the map
-        usable_size * 11 / 10
-    }
-
-    /// An inverse of `min_capacity`, approximately.
-    #[inline]
-    fn usable_capacity(&self, cap: usize) -> usize {
-        // As the number of entries approaches usable capacity,
-        // min_capacity(size) must be smaller than the internal capacity,
-        // so that the map is not resized:
-        // `min_capacity(usable_capacity(x)) <= x`.
-        // The left-hand side can only be smaller due to flooring by integer
-        // division.
-        //
-        // This doesn't have to be checked for overflow since allocation size
-        // in bytes will overflow earlier than multiplication by 10.
-        cap * 10 / 11
-    }
-}
-
-#[test]
-fn test_resize_policy() {
-    use prelude::v1::*;
-    let rp = DefaultResizePolicy;
-    for n in 0..1000 {
-        assert!(rp.min_capacity(rp.usable_capacity(n)) <= n);
-        assert!(rp.usable_capacity(rp.min_capacity(n)) <= n);
-    }
-}
-
-// The main performance trick in this hashmap is called Robin Hood Hashing.
-// It gains its excellent performance from one essential operation:
-//
-//    If an insertion collides with an existing element, and that element's
-//    "probe distance" (how far away the element is from its ideal location)
-//    is higher than how far we've already probed, swap the elements.
-//
-// This massively lowers variance in probe distance, and allows us to get very
-// high load factors with good performance. The 90% load factor I use is rather
-// conservative.
-//
-// > Why a load factor of approximately 90%?
-//
-// In general, all the distances to initial buckets will converge on the mean.
-// At a load factor of α, the odds of finding the target bucket after k
-// probes is approximately 1-α^k. If we set this equal to 50% (since we converge
-// on the mean) and set k=8 (64-byte cache line / 8-byte hash), α=0.92. I round
-// this down to make the math easier on the CPU and avoid its FPU.
-// Since on average we start the probing in the middle of a cache line, this
-// strategy pulls in two cache lines of hashes on every lookup. I think that's
-// pretty good, but if you want to trade off some space, it could go down to one
-// cache line on average with an α of 0.84.
-//
-// > Wait, what? Where did you get 1-α^k from?
-//
-// On the first probe, your odds of a collision with an existing element is α.
-// The odds of doing this twice in a row is approximately α^2. For three times,
-// α^3, etc. Therefore, the odds of colliding k times is α^k. The odds of NOT
-// colliding after k tries is 1-α^k.
-//
-// The paper from 1986 cited below mentions an implementation which keeps track
-// of the distance-to-initial-bucket histogram. This approach is not suitable
-// for modern architectures because it requires maintaining an internal data
-// structure. This allows very good first guesses, but we are most concerned
-// with guessing entire cache lines, not individual indexes. Furthermore, array
-// accesses are no longer linear and in one direction, as we have now. There
-// is also memory and cache pressure that this would entail that would be very
-// difficult to properly see in a microbenchmark.
-//
-// ## Future Improvements (FIXME!)
-//
-// Allow the load factor to be changed dynamically and/or at initialization.
-//
-// Also, would it be possible for us to reuse storage when growing the
-// underlying table? This is exactly the use case for 'realloc', and may
-// be worth exploring.
-//
-// ## Future Optimizations (FIXME!)
-//
-// Another possible design choice that I made without any real reason is
-// parameterizing the raw table over keys and values. Technically, all we need
-// is the size and alignment of keys and values, and the code should be just as
-// efficient (well, we might need one for power-of-two size and one for not...).
-// This has the potential to reduce code bloat in rust executables, without
-// really losing anything except 4 words (key size, key alignment, val size,
-// val alignment) which can be passed in to every call of a `RawTable` function.
-// This would definitely be an avenue worth exploring if people start complaining
-// about the size of rust executables.
-//
-// Annotate exceedingly likely branches in `table::make_hash`
-// and `search_hashed` to reduce instruction cache pressure
-// and mispredictions once it becomes possible (blocked on issue #11092).
-//
-// Shrinking the table could simply reallocate in place after moving buckets
-// to the first half.
-//
-// The growth algorithm (fragment of the Proof of Correctness)
-// --------------------
-//
-// The growth algorithm is basically a fast path of the naive reinsertion-
-// during-resize algorithm. Other paths should never be taken.
-//
-// Consider growing a robin hood hashtable of capacity n. Normally, we do this
-// by allocating a new table of capacity `2n`, and then individually reinsert
-// each element in the old table into the new one. This guarantees that the
-// new table is a valid robin hood hashtable with all the desired statistical
-// properties. Remark that the order we reinsert the elements in should not
-// matter. For simplicity and efficiency, we will consider only linear
-// reinsertions, which consist of reinserting all elements in the old table
-// into the new one by increasing order of index. However we will not be
-// starting our reinsertions from index 0 in general. If we start from index
-// i, for the purpose of reinsertion we will consider all elements with real
-// index j < i to have virtual index n + j.
-//
-// Our hash generation scheme consists of generating a 64-bit hash and
-// truncating the most significant bits. When moving to the new table, we
-// simply introduce a new bit to the front of the hash. Therefore, if an
-// elements has ideal index i in the old table, it can have one of two ideal
-// locations in the new table. If the new bit is 0, then the new ideal index
-// is i. If the new bit is 1, then the new ideal index is n + i. Intuitively,
-// we are producing two independent tables of size n, and for each element we
-// independently choose which table to insert it into with equal probability.
-// However the rather than wrapping around themselves on overflowing their
-// indexes, the first table overflows into the first, and the first into the
-// second. Visually, our new table will look something like:
-//
-// [yy_xxx_xxxx_xxx|xx_yyy_yyyy_yyy]
-//
-// Where x's are elements inserted into the first table, y's are elements
-// inserted into the second, and _'s are empty sections. We now define a few
-// key concepts that we will use later. Note that this is a very abstract
-// perspective of the table. A real resized table would be at least half
-// empty.
-//
-// Theorem: A linear robin hood reinsertion from the first ideal element
-// produces identical results to a linear naive reinsertion from the same
-// element.
-//
-// FIXME(Gankro, pczarn): review the proof and put it all in a separate doc.rs
-
-/// A hash map implementation which uses linear probing with Robin
-/// Hood bucket stealing.
-///
-/// The hashes are all keyed by the task-local random number generator
-/// on creation by default. This means that the ordering of the keys is
-/// randomized, but makes the tables more resistant to
-/// denial-of-service attacks (Hash DoS). This behaviour can be
-/// overridden with one of the constructors.
-///
-/// It is required that the keys implement the `Eq` and `Hash` traits, although
-/// this can frequently be achieved by using `#[derive(Eq, Hash)]`.
-///
-/// Relevant papers/articles:
-///
-/// 1. Pedro Celis. ["Robin Hood Hashing"](https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf)
-/// 2. Emmanuel Goossaert. ["Robin Hood
-///    hashing"](http://codecapsule.com/2013/11/11/robin-hood-hashing/)
-/// 3. Emmanuel Goossaert. ["Robin Hood hashing: backward shift
-///    deletion"](http://codecapsule.com/2013/11/17/robin-hood-hashing-backward-shift-deletion/)
-///
-/// # Example
-///
-/// ```
-/// use std::collections::HashMap;
-///
-/// // type inference lets us omit an explicit type signature (which
-/// // would be `HashMap<&str, &str>` in this example).
-/// let mut book_reviews = HashMap::new();
-///
-/// // review some books.
-/// book_reviews.insert("Adventures of Huckleberry Finn",    "My favorite book.");
-/// book_reviews.insert("Grimms' Fairy Tales",               "Masterpiece.");
-/// book_reviews.insert("Pride and Prejudice",               "Very enjoyable.");
-/// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot.");
-///
-/// // check for a specific one.
-/// if !book_reviews.contains_key(&("Les Misérables")) {
-///     println!("We've got {} reviews, but Les Misérables ain't one.",
-///              book_reviews.len());
-/// }
-///
-/// // oops, this review has a lot of spelling mistakes, let's delete it.
-/// book_reviews.remove(&("The Adventures of Sherlock Holmes"));
-///
-/// // look up the values associated with some keys.
-/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
-/// for book in to_find.iter() {
-///     match book_reviews.get(book) {
-///         Some(review) => println!("{}: {}", *book, *review),
-///         None => println!("{} is unreviewed.", *book)
-///     }
-/// }
-///
-/// // iterate over everything.
-/// for (book, review) in book_reviews.iter() {
-///     println!("{}: \"{}\"", *book, *review);
-/// }
-/// ```
-///
-/// The easiest way to use `HashMap` with a custom type as key is to derive `Eq` and `Hash`.
-/// We must also derive `PartialEq`.
-///
-/// ```
-/// use std::collections::HashMap;
-///
-/// #[derive(Hash, Eq, PartialEq, Debug)]
-/// struct Viking {
-///     name: String,
-///     country: String,
-/// }
-///
-/// impl Viking {
-///     /// Create a new Viking.
-///     fn new(name: &str, country: &str) -> Viking {
-///         Viking { name: name.to_string(), country: country.to_string() }
-///     }
-/// }
-///
-/// // Use a HashMap to store the vikings' health points.
-/// let mut vikings = HashMap::new();
-///
-/// vikings.insert(Viking::new("Einar", "Norway"), 25);
-/// vikings.insert(Viking::new("Olaf", "Denmark"), 24);
-/// vikings.insert(Viking::new("Harald", "Iceland"), 12);
-///
-/// // Use derived implementation to print the status of the vikings.
-/// for (viking, health) in vikings.iter() {
-///     println!("{:?} has {} hp", viking, health);
-/// }
-/// ```
-#[derive(Clone)]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct HashMap<K, V, S = RandomState> {
-    // All hashes are keyed on these values, to prevent hash collision attacks.
-    hash_state: S,
-
-    table: RawTable<K, V>,
-
-    resize_policy: DefaultResizePolicy,
-}
-
-/// Search for a pre-hashed key.
-fn search_hashed<K, V, M, F>(table: M,
-                             hash: SafeHash,
-                             mut is_match: F)
-                             -> SearchResult<K, V, M> where
-    M: Deref<Target=RawTable<K, V>>,
-    F: FnMut(&K) -> bool,
-{
-    let size = table.size();
-    let mut probe = Bucket::new(table, hash);
-    let ib = probe.index();
-
-    while probe.index() != ib + size {
-        let full = match probe.peek() {
-            Empty(b) => return TableRef(b.into_table()), // hit an empty bucket
-            Full(b) => b
-        };
-
-        if full.distance() + ib < full.index() {
-            // We can finish the search early if we hit any bucket
-            // with a lower distance to initial bucket than we've probed.
-            return TableRef(full.into_table());
-        }
-
-        // If the hash doesn't match, it can't be this one..
-        if hash == full.hash() {
-            // If the key doesn't match, it can't be this one..
-            if is_match(full.read().0) {
-                return FoundExisting(full);
-            }
-        }
-
-        probe = full.next();
-    }
-
-    TableRef(probe.into_table())
-}
-
-fn pop_internal<K, V>(starting_bucket: FullBucketMut<K, V>) -> (K, V) {
-    let (empty, retkey, retval) = starting_bucket.take();
-    let mut gap = match empty.gap_peek() {
-        Some(b) => b,
-        None => return (retkey, retval)
-    };
-
-    while gap.full().distance() != 0 {
-        gap = match gap.shift() {
-            Some(b) => b,
-            None => break
-        };
-    }
-
-    // Now we've done all our shifting. Return the value we grabbed earlier.
-    (retkey, retval)
-}
-
-/// Perform robin hood bucket stealing at the given `bucket`. You must
-/// also pass the position of that bucket's initial bucket so we don't have
-/// to recalculate it.
-///
-/// `hash`, `k`, and `v` are the elements to "robin hood" into the hashtable.
-fn robin_hood<'a, K: 'a, V: 'a>(mut bucket: FullBucketMut<'a, K, V>,
-                        mut ib: usize,
-                        mut hash: SafeHash,
-                        mut k: K,
-                        mut v: V)
-                        -> &'a mut V {
-    let starting_index = bucket.index();
-    let size = {
-        let table = bucket.table(); // FIXME "lifetime too short".
-        table.size()
-    };
-    // There can be at most `size - dib` buckets to displace, because
-    // in the worst case, there are `size` elements and we already are
-    // `distance` buckets away from the initial one.
-    let idx_end = starting_index + size - bucket.distance();
-
-    loop {
-        let (old_hash, old_key, old_val) = bucket.replace(hash, k, v);
-        loop {
-            let probe = bucket.next();
-            assert!(probe.index() != idx_end);
-
-            let full_bucket = match probe.peek() {
-                Empty(bucket) => {
-                    // Found a hole!
-                    let b = bucket.put(old_hash, old_key, old_val);
-                    // Now that it's stolen, just read the value's pointer
-                    // right out of the table!
-                    return Bucket::at_index(b.into_table(), starting_index)
-                               .peek()
-                               .expect_full()
-                               .into_mut_refs()
-                               .1;
-                },
-                Full(bucket) => bucket
-            };
-
-            let probe_ib = full_bucket.index() - full_bucket.distance();
-
-            bucket = full_bucket;
-
-            // Robin hood! Steal the spot.
-            if ib < probe_ib {
-                ib = probe_ib;
-                hash = old_hash;
-                k = old_key;
-                v = old_val;
-                break;
-            }
-        }
-    }
-}
-
-/// A result that works like Option<FullBucket<..>> but preserves
-/// the reference that grants us access to the table in any case.
-enum SearchResult<K, V, M> {
-    // This is an entry that holds the given key:
-    FoundExisting(FullBucket<K, V, M>),
-
-    // There was no such entry. The reference is given back:
-    TableRef(M)
-}
-
-impl<K, V, M> SearchResult<K, V, M> {
-    fn into_option(self) -> Option<FullBucket<K, V, M>> {
-        match self {
-            FoundExisting(bucket) => Some(bucket),
-            TableRef(_) => None
-        }
-    }
-}
-
-impl<K, V, S, H> HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn make_hash<X: ?Sized>(&self, x: &X) -> SafeHash where X: Hash<H> {
-        table::make_hash(&self.hash_state, x)
-    }
-
-    /// Search for a key, yielding the index if it's found in the hashtable.
-    /// If you already have the hash for the key lying around, use
-    /// search_hashed.
-    fn search<'a, Q: ?Sized>(&'a self, q: &Q) -> Option<FullBucketImm<'a, K, V>>
-        where K: Borrow<Q>, Q: Eq + Hash<H>
-    {
-        let hash = self.make_hash(q);
-        search_hashed(&self.table, hash, |k| q.eq(k.borrow()))
-            .into_option()
-    }
-
-    fn search_mut<'a, Q: ?Sized>(&'a mut self, q: &Q) -> Option<FullBucketMut<'a, K, V>>
-        where K: Borrow<Q>, Q: Eq + Hash<H>
-    {
-        let hash = self.make_hash(q);
-        search_hashed(&mut self.table, hash, |k| q.eq(k.borrow()))
-            .into_option()
-    }
-
-    // The caller should ensure that invariants by Robin Hood Hashing hold.
-    fn insert_hashed_ordered(&mut self, hash: SafeHash, k: K, v: V) {
-        let cap = self.table.capacity();
-        let mut buckets = Bucket::new(&mut self.table, hash);
-        let ib = buckets.index();
-
-        while buckets.index() != ib + cap {
-            // We don't need to compare hashes for value swap.
-            // Not even DIBs for Robin Hood.
-            buckets = match buckets.peek() {
-                Empty(empty) => {
-                    empty.put(hash, k, v);
-                    return;
-                }
-                Full(b) => b.into_bucket()
-            };
-            buckets.next();
-        }
-        panic!("Internal HashMap error: Out of space.");
-    }
-}
-
-impl<K: Hash<Hasher> + Eq, V> HashMap<K, V, RandomState> {
-    /// Create an empty HashMap.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// let mut map: HashMap<&str, int> = HashMap::new();
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn new() -> HashMap<K, V, RandomState> {
-        Default::default()
-    }
-
-    /// Creates an empty hash map with the given initial capacity.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// let mut map: HashMap<&str, int> = HashMap::with_capacity(10);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn with_capacity(capacity: usize) -> HashMap<K, V, RandomState> {
-        HashMap::with_capacity_and_hash_state(capacity, Default::default())
-    }
-}
-
-impl<K, V, S, H> HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    /// Creates an empty hashmap which will use the given hasher to hash keys.
-    ///
-    /// The creates map has the default initial capacity.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// use std::collections::hash_map::RandomState;
-    ///
-    /// let s = RandomState::new();
-    /// let mut map = HashMap::with_hash_state(s);
-    /// map.insert(1, 2);
-    /// ```
-    #[inline]
-    #[unstable(feature = "std_misc", reason = "hasher stuff is unclear")]
-    pub fn with_hash_state(hash_state: S) -> HashMap<K, V, S> {
-        HashMap {
-            hash_state:    hash_state,
-            resize_policy: DefaultResizePolicy::new(),
-            table:         RawTable::new(0),
-        }
-    }
-
-    /// Create an empty HashMap with space for at least `capacity`
-    /// elements, using `hasher` to hash the keys.
-    ///
-    /// Warning: `hasher` is normally randomly generated, and
-    /// is designed to allow HashMaps to be resistant to attacks that
-    /// cause many collisions and very poor performance. Setting it
-    /// manually using this function can expose a DoS attack vector.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// use std::collections::hash_map::RandomState;
-    ///
-    /// let s = RandomState::new();
-    /// let mut map = HashMap::with_capacity_and_hash_state(10, s);
-    /// map.insert(1, 2);
-    /// ```
-    #[inline]
-    #[unstable(feature = "std_misc", reason = "hasher stuff is unclear")]
-    pub fn with_capacity_and_hash_state(capacity: usize, hash_state: S)
-                                        -> HashMap<K, V, S> {
-        let resize_policy = DefaultResizePolicy::new();
-        let min_cap = max(INITIAL_CAPACITY, resize_policy.min_capacity(capacity));
-        let internal_cap = min_cap.checked_next_power_of_two().expect("capacity overflow");
-        assert!(internal_cap >= capacity, "capacity overflow");
-        HashMap {
-            hash_state:    hash_state,
-            resize_policy: resize_policy,
-            table:         RawTable::new(internal_cap),
-        }
-    }
-
-    /// Returns the number of elements the map can hold without reallocating.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// let map: HashMap<int, int> = HashMap::with_capacity(100);
-    /// assert!(map.capacity() >= 100);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn capacity(&self) -> usize {
-        self.resize_policy.usable_capacity(self.table.capacity())
-    }
-
-    /// Reserves capacity for at least `additional` more elements to be inserted
-    /// in the `HashMap`. The collection may reserve more space to avoid
-    /// frequent reallocations.
-    ///
-    /// # Panics
-    ///
-    /// Panics if the new allocation size overflows `usize`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    /// let mut map: HashMap<&str, int> = HashMap::new();
-    /// map.reserve(10);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn reserve(&mut self, additional: usize) {
-        let new_size = self.len().checked_add(additional).expect("capacity overflow");
-        let min_cap = self.resize_policy.min_capacity(new_size);
-
-        // An invalid value shouldn't make us run out of space. This includes
-        // an overflow check.
-        assert!(new_size <= min_cap);
-
-        if self.table.capacity() < min_cap {
-            let new_capacity = max(min_cap.next_power_of_two(), INITIAL_CAPACITY);
-            self.resize(new_capacity);
-        }
-    }
-
-    /// Resizes the internal vectors to a new capacity. It's your responsibility to:
-    ///   1) Make sure the new capacity is enough for all the elements, accounting
-    ///      for the load factor.
-    ///   2) Ensure new_capacity is a power of two or zero.
-    fn resize(&mut self, new_capacity: usize) {
-        assert!(self.table.size() <= new_capacity);
-        assert!(new_capacity.is_power_of_two() || new_capacity == 0);
-
-        let mut old_table = replace(&mut self.table, RawTable::new(new_capacity));
-        let old_size = old_table.size();
-
-        if old_table.capacity() == 0 || old_table.size() == 0 {
-            return;
-        }
-
-        // Grow the table.
-        // Specialization of the other branch.
-        let mut bucket = Bucket::first(&mut old_table);
-
-        // "So a few of the first shall be last: for many be called,
-        // but few chosen."
-        //
-        // We'll most likely encounter a few buckets at the beginning that
-        // have their initial buckets near the end of the table. They were
-        // placed at the beginning as the probe wrapped around the table
-        // during insertion. We must skip forward to a bucket that won't
-        // get reinserted too early and won't unfairly steal others spot.
-        // This eliminates the need for robin hood.
-        loop {
-            bucket = match bucket.peek() {
-                Full(full) => {
-                    if full.distance() == 0 {
-                        // This bucket occupies its ideal spot.
-                        // It indicates the start of another "cluster".
-                        bucket = full.into_bucket();
-                        break;
-                    }
-                    // Leaving this bucket in the last cluster for later.
-                    full.into_bucket()
-                }
-                Empty(b) => {
-                    // Encountered a hole between clusters.
-                    b.into_bucket()
-                }
-            };
-            bucket.next();
-        }
-
-        // This is how the buckets might be laid out in memory:
-        // ($ marks an initialized bucket)
-        //  ________________
-        // |$$$_$$$$$$_$$$$$|
-        //
-        // But we've skipped the entire initial cluster of buckets
-        // and will continue iteration in this order:
-        //  ________________
-        //     |$$$$$$_$$$$$
-        //                  ^ wrap around once end is reached
-        //  ________________
-        //  $$$_____________|
-        //    ^ exit once table.size == 0
-        loop {
-            bucket = match bucket.peek() {
-                Full(bucket) => {
-                    let h = bucket.hash();
-                    let (b, k, v) = bucket.take();
-                    self.insert_hashed_ordered(h, k, v);
-                    {
-                        let t = b.table(); // FIXME "lifetime too short".
-                        if t.size() == 0 { break }
-                    };
-                    b.into_bucket()
-                }
-                Empty(b) => b.into_bucket()
-            };
-            bucket.next();
-        }
-
-        assert_eq!(self.table.size(), old_size);
-    }
-
-    /// Shrinks the capacity of the map as much as possible. It will drop
-    /// down as much as possible while maintaining the internal rules
-    /// and possibly leaving some space in accordance with the resize policy.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map: HashMap<int, int> = HashMap::with_capacity(100);
-    /// map.insert(1, 2);
-    /// map.insert(3, 4);
-    /// assert!(map.capacity() >= 100);
-    /// map.shrink_to_fit();
-    /// assert!(map.capacity() >= 2);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn shrink_to_fit(&mut self) {
-        let min_capacity = self.resize_policy.min_capacity(self.len());
-        let min_capacity = max(min_capacity.next_power_of_two(), INITIAL_CAPACITY);
-
-        // An invalid value shouldn't make us run out of space.
-        debug_assert!(self.len() <= min_capacity);
-
-        if self.table.capacity() != min_capacity {
-            let old_table = replace(&mut self.table, RawTable::new(min_capacity));
-            let old_size = old_table.size();
-
-            // Shrink the table. Naive algorithm for resizing:
-            for (h, k, v) in old_table.into_iter() {
-                self.insert_hashed_nocheck(h, k, v);
-            }
-
-            debug_assert_eq!(self.table.size(), old_size);
-        }
-    }
-
-    /// Insert a pre-hashed key-value pair, without first checking
-    /// that there's enough room in the buckets. Returns a reference to the
-    /// newly insert value.
-    ///
-    /// If the key already exists, the hashtable will be returned untouched
-    /// and a reference to the existing element will be returned.
-    fn insert_hashed_nocheck(&mut self, hash: SafeHash, k: K, v: V) -> &mut V {
-        self.insert_or_replace_with(hash, k, v, |_, _, _| ())
-    }
-
-    fn insert_or_replace_with<'a, F>(&'a mut self,
-                                     hash: SafeHash,
-                                     k: K,
-                                     v: V,
-                                     mut found_existing: F)
-                                     -> &'a mut V where
-        F: FnMut(&mut K, &mut V, V),
-    {
-        // Worst case, we'll find one empty bucket among `size + 1` buckets.
-        let size = self.table.size();
-        let mut probe = Bucket::new(&mut self.table, hash);
-        let ib = probe.index();
-
-        loop {
-            let mut bucket = match probe.peek() {
-                Empty(bucket) => {
-                    // Found a hole!
-                    return bucket.put(hash, k, v).into_mut_refs().1;
-                }
-                Full(bucket) => bucket
-            };
-
-            // hash matches?
-            if bucket.hash() == hash {
-                // key matches?
-                if k == *bucket.read_mut().0 {
-                    let (bucket_k, bucket_v) = bucket.into_mut_refs();
-                    debug_assert!(k == *bucket_k);
-                    // Key already exists. Get its reference.
-                    found_existing(bucket_k, bucket_v, v);
-                    return bucket_v;
-                }
-            }
-
-            let robin_ib = bucket.index() as int - bucket.distance() as int;
-
-            if (ib as int) < robin_ib {
-                // Found a luckier bucket than me. Better steal his spot.
-                return robin_hood(bucket, robin_ib as usize, hash, k, v);
-            }
-
-            probe = bucket.next();
-            assert!(probe.index() != ib + size + 1);
-        }
-    }
-
-    /// An iterator visiting all keys in arbitrary order.
-    /// Iterator element type is `&'a K`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert("a", 1);
-    /// map.insert("b", 2);
-    /// map.insert("c", 3);
-    ///
-    /// for key in map.keys() {
-    ///     println!("{}", key);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn keys<'a>(&'a self) -> Keys<'a, K, V> {
-        fn first<A, B>((a, _): (A, B)) -> A { a }
-        let first: fn((&'a K,&'a V)) -> &'a K = first; // coerce to fn ptr
-
-        Keys { inner: self.iter().map(first) }
-    }
-
-    /// An iterator visiting all values in arbitrary order.
-    /// Iterator element type is `&'a V`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert("a", 1);
-    /// map.insert("b", 2);
-    /// map.insert("c", 3);
-    ///
-    /// for val in map.values() {
-    ///     println!("{}", val);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn values<'a>(&'a self) -> Values<'a, K, V> {
-        fn second<A, B>((_, b): (A, B)) -> B { b }
-        let second: fn((&'a K,&'a V)) -> &'a V = second; // coerce to fn ptr
-
-        Values { inner: self.iter().map(second) }
-    }
-
-    /// An iterator visiting all key-value pairs in arbitrary order.
-    /// Iterator element type is `(&'a K, &'a V)`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert("a", 1);
-    /// map.insert("b", 2);
-    /// map.insert("c", 3);
-    ///
-    /// for (key, val) in map.iter() {
-    ///     println!("key: {} val: {}", key, val);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<K, V> {
-        Iter { inner: self.table.iter() }
-    }
-
-    /// An iterator visiting all key-value pairs in arbitrary order,
-    /// with mutable references to the values.
-    /// Iterator element type is `(&'a K, &'a mut V)`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert("a", 1);
-    /// map.insert("b", 2);
-    /// map.insert("c", 3);
-    ///
-    /// // Update all values
-    /// for (_, val) in map.iter_mut() {
-    ///     *val *= 2;
-    /// }
-    ///
-    /// for (key, val) in map.iter() {
-    ///     println!("key: {} val: {}", key, val);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter_mut(&mut self) -> IterMut<K, V> {
-        IterMut { inner: self.table.iter_mut() }
-    }
-
-    /// Creates a consuming iterator, that is, one that moves each key-value
-    /// pair out of the map in arbitrary order. The map cannot be used after
-    /// calling this.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert("a", 1);
-    /// map.insert("b", 2);
-    /// map.insert("c", 3);
-    ///
-    /// // Not possible with .iter()
-    /// let vec: Vec<(&str, int)> = map.into_iter().collect();
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn into_iter(self) -> IntoIter<K, V> {
-        fn last_two<A, B, C>((_, b, c): (A, B, C)) -> (B, C) { (b, c) }
-        let last_two: fn((SafeHash, K, V)) -> (K, V) = last_two;
-
-        IntoIter {
-            inner: self.table.into_iter().map(last_two)
-        }
-    }
-
-    /// Gets the given key's corresponding entry in the map for in-place manipulation.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn entry(&mut self, key: K) -> Entry<K, V> {
-        // Gotta resize now.
-        self.reserve(1);
-
-        let hash = self.make_hash(&key);
-        search_entry_hashed(&mut self.table, hash, key)
-    }
-
-    /// Returns the number of elements in the map.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut a = HashMap::new();
-    /// assert_eq!(a.len(), 0);
-    /// a.insert(1, "a");
-    /// assert_eq!(a.len(), 1);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn len(&self) -> usize { self.table.size() }
-
-    /// Returns true if the map contains no elements.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut a = HashMap::new();
-    /// assert!(a.is_empty());
-    /// a.insert(1, "a");
-    /// assert!(!a.is_empty());
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn is_empty(&self) -> bool { self.len() == 0 }
-
-    /// Clears the map, returning all key-value pairs as an iterator. Keeps the
-    /// allocated memory for reuse.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut a = HashMap::new();
-    /// a.insert(1, "a");
-    /// a.insert(2, "b");
-    ///
-    /// for (k, v) in a.drain().take(1) {
-    ///     assert!(k == 1 || k == 2);
-    ///     assert!(v == "a" || v == "b");
-    /// }
-    ///
-    /// assert!(a.is_empty());
-    /// ```
-    #[inline]
-    #[unstable(feature = "std_misc",
-               reason = "matches collection reform specification, waiting for dust to settle")]
-    pub fn drain(&mut self) -> Drain<K, V> {
-        fn last_two<A, B, C>((_, b, c): (A, B, C)) -> (B, C) { (b, c) }
-        let last_two: fn((SafeHash, K, V)) -> (K, V) = last_two; // coerce to fn pointer
-
-        Drain {
-            inner: self.table.drain().map(last_two),
-        }
-    }
-
-    /// Clears the map, removing all key-value pairs. Keeps the allocated memory
-    /// for reuse.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut a = HashMap::new();
-    /// a.insert(1, "a");
-    /// a.clear();
-    /// assert!(a.is_empty());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    #[inline]
-    pub fn clear(&mut self) {
-        self.drain();
-    }
-
-    /// Returns a reference to the value corresponding to the key.
-    ///
-    /// The key may be any borrowed form of the map's key type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the key type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert(1, "a");
-    /// assert_eq!(map.get(&1), Some(&"a"));
-    /// assert_eq!(map.get(&2), None);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
-        where K: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        self.search(k).map(|bucket| bucket.into_refs().1)
-    }
-
-    /// Returns true if the map contains a value for the specified key.
-    ///
-    /// The key may be any borrowed form of the map's key type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the key type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert(1, "a");
-    /// assert_eq!(map.contains_key(&1), true);
-    /// assert_eq!(map.contains_key(&2), false);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn contains_key<Q: ?Sized>(&self, k: &Q) -> bool
-        where K: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        self.search(k).is_some()
-    }
-
-    /// Returns a mutable reference to the value corresponding to the key.
-    ///
-    /// The key may be any borrowed form of the map's key type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the key type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert(1, "a");
-    /// match map.get_mut(&1) {
-    ///     Some(x) => *x = "b",
-    ///     None => (),
-    /// }
-    /// assert_eq!(map[1], "b");
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
-        where K: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        self.search_mut(k).map(|bucket| bucket.into_mut_refs().1)
-    }
-
-    /// Inserts a key-value pair from the map. If the key already had a value
-    /// present in the map, that value is returned. Otherwise, `None` is returned.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// assert_eq!(map.insert(37, "a"), None);
-    /// assert_eq!(map.is_empty(), false);
-    ///
-    /// map.insert(37, "b");
-    /// assert_eq!(map.insert(37, "c"), Some("b"));
-    /// assert_eq!(map[37], "c");
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn insert(&mut self, k: K, v: V) -> Option<V> {
-        let hash = self.make_hash(&k);
-        self.reserve(1);
-
-        let mut retval = None;
-        self.insert_or_replace_with(hash, k, v, |_, val_ref, val| {
-            retval = Some(replace(val_ref, val));
-        });
-        retval
-    }
-
-    /// Removes a key from the map, returning the value at the key if the key
-    /// was previously in the map.
-    ///
-    /// The key may be any borrowed form of the map's key type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the key type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashMap;
-    ///
-    /// let mut map = HashMap::new();
-    /// map.insert(1, "a");
-    /// assert_eq!(map.remove(&1), Some("a"));
-    /// assert_eq!(map.remove(&1), None);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
-        where K: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        if self.table.size() == 0 {
-            return None
-        }
-
-        self.search_mut(k).map(|bucket| pop_internal(bucket).1)
-    }
-}
-
-fn search_entry_hashed<'a, K: Eq, V>(table: &'a mut RawTable<K,V>, hash: SafeHash, k: K)
-        -> Entry<'a, K, V>
-{
-    // Worst case, we'll find one empty bucket among `size + 1` buckets.
-    let size = table.size();
-    let mut probe = Bucket::new(table, hash);
-    let ib = probe.index();
-
-    loop {
-        let bucket = match probe.peek() {
-            Empty(bucket) => {
-                // Found a hole!
-                return Vacant(VacantEntry {
-                    hash: hash,
-                    key: k,
-                    elem: NoElem(bucket),
-                });
-            },
-            Full(bucket) => bucket
-        };
-
-        // hash matches?
-        if bucket.hash() == hash {
-            // key matches?
-            if k == *bucket.read().0 {
-                return Occupied(OccupiedEntry{
-                    elem: bucket,
-                });
-            }
-        }
-
-        let robin_ib = bucket.index() as int - bucket.distance() as int;
-
-        if (ib as int) < robin_ib {
-            // Found a luckier bucket than me. Better steal his spot.
-            return Vacant(VacantEntry {
-                hash: hash,
-                key: k,
-                elem: NeqElem(bucket, robin_ib as usize),
-            });
-        }
-
-        probe = bucket.next();
-        assert!(probe.index() != ib + size + 1);
-    }
-}
-
-impl<K, V, S, H> PartialEq for HashMap<K, V, S>
-    where K: Eq + Hash<H>, V: PartialEq,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn eq(&self, other: &HashMap<K, V, S>) -> bool {
-        if self.len() != other.len() { return false; }
-
-        self.iter().all(|(key, value)|
-            other.get(key).map_or(false, |v| *value == *v)
-        )
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H> Eq for HashMap<K, V, S>
-    where K: Eq + Hash<H>, V: Eq,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H> Debug for HashMap<K, V, S>
-    where K: Eq + Hash<H> + Debug, V: Debug,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(f, "HashMap {{"));
-
-        for (i, (k, v)) in self.iter().enumerate() {
-            if i != 0 { try!(write!(f, ", ")); }
-            try!(write!(f, "{:?}: {:?}", *k, *v));
-        }
-
-        write!(f, "}}")
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H> Default for HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    fn default() -> HashMap<K, V, S> {
-        HashMap::with_hash_state(Default::default())
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, Q: ?Sized, V, S, H> Index<Q> for HashMap<K, V, S>
-    where K: Eq + Hash<H> + Borrow<Q>,
-          Q: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Output = V;
-
-    #[inline]
-    fn index<'a>(&'a self, index: &Q) -> &'a V {
-        self.get(index).expect("no entry found for key")
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H, Q: ?Sized> IndexMut<Q> for HashMap<K, V, S>
-    where K: Eq + Hash<H> + Borrow<Q>,
-          Q: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    #[inline]
-    fn index_mut<'a>(&'a mut self, index: &Q) -> &'a mut V {
-        self.get_mut(index).expect("no entry found for key")
-    }
-}
-
-/// HashMap iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Iter<'a, K: 'a, V: 'a> {
-    inner: table::Iter<'a, K, V>
-}
-
-// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for Iter<'a, K, V> {
-    fn clone(&self) -> Iter<'a, K, V> {
-        Iter {
-            inner: self.inner.clone()
-        }
-    }
-}
-
-/// HashMap mutable values iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct IterMut<'a, K: 'a, V: 'a> {
-    inner: table::IterMut<'a, K, V>
-}
-
-/// HashMap move iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct IntoIter<K, V> {
-    inner: iter::Map<table::IntoIter<K, V>, fn((SafeHash, K, V)) -> (K, V)>
-}
-
-/// HashMap keys iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Keys<'a, K: 'a, V: 'a> {
-    inner: Map<Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a K>
-}
-
-// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for Keys<'a, K, V> {
-    fn clone(&self) -> Keys<'a, K, V> {
-        Keys {
-            inner: self.inner.clone()
-        }
-    }
-}
-
-/// HashMap values iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Values<'a, K: 'a, V: 'a> {
-    inner: Map<Iter<'a, K, V>, fn((&'a K, &'a V)) -> &'a V>
-}
-
-// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
-impl<'a, K, V> Clone for Values<'a, K, V> {
-    fn clone(&self) -> Values<'a, K, V> {
-        Values {
-            inner: self.inner.clone()
-        }
-    }
-}
-
-/// HashMap drain iterator.
-#[unstable(feature = "std_misc",
-           reason = "matches collection reform specification, waiting for dust to settle")]
-pub struct Drain<'a, K: 'a, V: 'a> {
-    inner: iter::Map<table::Drain<'a, K, V>, fn((SafeHash, K, V)) -> (K, V)>
-}
-
-/// A view into a single occupied location in a HashMap.
-#[unstable(feature = "std_misc",
-           reason = "precise API still being fleshed out")]
-pub struct OccupiedEntry<'a, K: 'a, V: 'a> {
-    elem: FullBucket<K, V, &'a mut RawTable<K, V>>,
-}
-
-/// A view into a single empty location in a HashMap.
-#[unstable(feature = "std_misc",
-           reason = "precise API still being fleshed out")]
-pub struct VacantEntry<'a, K: 'a, V: 'a> {
-    hash: SafeHash,
-    key: K,
-    elem: VacantEntryState<K, V, &'a mut RawTable<K, V>>,
-}
-
-/// A view into a single location in a map, which may be vacant or occupied.
-#[unstable(feature = "std_misc",
-           reason = "precise API still being fleshed out")]
-pub enum Entry<'a, K: 'a, V: 'a> {
-    /// An occupied Entry.
-    Occupied(OccupiedEntry<'a, K, V>),
-    /// A vacant Entry.
-    Vacant(VacantEntry<'a, K, V>),
-}
-
-/// Possible states of a VacantEntry.
-enum VacantEntryState<K, V, M> {
-    /// The index is occupied, but the key to insert has precedence,
-    /// and will kick the current one out on insertion.
-    NeqElem(FullBucket<K, V, M>, usize),
-    /// The index is genuinely vacant.
-    NoElem(EmptyBucket<K, V, M>),
-}
-
-impl<'a, K, V, S, H> IntoIterator for &'a HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = (&'a K, &'a V);
-    type IntoIter = Iter<'a, K, V>;
-
-    fn into_iter(self) -> Iter<'a, K, V> {
-        self.iter()
-    }
-}
-
-impl<'a, K, V, S, H> IntoIterator for &'a mut HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = (&'a K, &'a mut V);
-    type IntoIter = IterMut<'a, K, V>;
-
-    fn into_iter(mut self) -> IterMut<'a, K, V> {
-        self.iter_mut()
-    }
-}
-
-impl<K, V, S, H> IntoIterator for HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = (K, V);
-    type IntoIter = IntoIter<K, V>;
-
-    fn into_iter(self) -> IntoIter<K, V> {
-        self.into_iter()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Iterator for Iter<'a, K, V> {
-    type Item = (&'a K, &'a V);
-
-    #[inline] fn next(&mut self) -> Option<(&'a K, &'a V)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Iter<'a, K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Iterator for IterMut<'a, K, V> {
-    type Item = (&'a K, &'a mut V);
-
-    #[inline] fn next(&mut self) -> Option<(&'a K, &'a mut V)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for IterMut<'a, K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V> Iterator for IntoIter<K, V> {
-    type Item = (K, V);
-
-    #[inline] fn next(&mut self) -> Option<(K, V)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V> ExactSizeIterator for IntoIter<K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Iterator for Keys<'a, K, V> {
-    type Item = &'a K;
-
-    #[inline] fn next(&mut self) -> Option<(&'a K)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Keys<'a, K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Iterator for Values<'a, K, V> {
-    type Item = &'a V;
-
-    #[inline] fn next(&mut self) -> Option<(&'a V)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Values<'a, K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> Iterator for Drain<'a, K, V> {
-    type Item = (K, V);
-
-    #[inline] fn next(&mut self) -> Option<(K, V)> { self.inner.next() }
-    #[inline] fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K, V> ExactSizeIterator for Drain<'a, K, V> {
-    #[inline] fn len(&self) -> usize { self.inner.len() }
-}
-
-#[unstable(feature = "std_misc",
-           reason = "matches collection reform v2 specification, waiting for dust to settle")]
-impl<'a, K, V> Entry<'a, K, V> {
-    /// Returns a mutable reference to the entry if occupied, or the VacantEntry if vacant.
-    pub fn get(self) -> Result<&'a mut V, VacantEntry<'a, K, V>> {
-        match self {
-            Occupied(entry) => Ok(entry.into_mut()),
-            Vacant(entry) => Err(entry),
-        }
-    }
-}
-
-impl<'a, K, V> OccupiedEntry<'a, K, V> {
-    /// Gets a reference to the value in the entry.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn get(&self) -> &V {
-        self.elem.read().1
-    }
-
-    /// Gets a mutable reference to the value in the entry.
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn get_mut(&mut self) -> &mut V {
-        self.elem.read_mut().1
-    }
-
-    /// Converts the OccupiedEntry into a mutable reference to the value in the entry
-    /// with a lifetime bound to the map itself
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn into_mut(self) -> &'a mut V {
-        self.elem.into_mut_refs().1
-    }
-
-    /// Sets the value of the entry, and returns the entry's old value
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn insert(&mut self, mut value: V) -> V {
-        let old_value = self.get_mut();
-        mem::swap(&mut value, old_value);
-        value
-    }
-
-    /// Takes the value out of the entry, and returns it
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn remove(self) -> V {
-        pop_internal(self.elem).1
-    }
-}
-
-impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> {
-    /// Sets the value of the entry with the VacantEntry's key,
-    /// and returns a mutable reference to it
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn insert(self, value: V) -> &'a mut V {
-        match self.elem {
-            NeqElem(bucket, ib) => {
-                robin_hood(bucket, ib, self.hash, self.key, value)
-            }
-            NoElem(bucket) => {
-                bucket.put(self.hash, self.key, value).into_mut_refs().1
-            }
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H> FromIterator<(K, V)> for HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    fn from_iter<T: IntoIterator<Item=(K, V)>>(iter: T) -> HashMap<K, V, S> {
-        let iter = iter.into_iter();
-        let lower = iter.size_hint().0;
-        let mut map = HashMap::with_capacity_and_hash_state(lower,
-                                                            Default::default());
-        map.extend(iter);
-        map
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K, V, S, H> Extend<(K, V)> for HashMap<K, V, S>
-    where K: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn extend<T: IntoIterator<Item=(K, V)>>(&mut self, iter: T) {
-        for (k, v) in iter {
-            self.insert(k, v);
-        }
-    }
-}
-
-
-/// `RandomState` is the default state for `HashMap` types.
-///
-/// A particular instance `RandomState` will create the same instances of
-/// `Hasher`, but the hashers created by two different `RandomState`
-/// instances are unlikely to produce the same result for the same values.
-#[derive(Clone)]
-#[unstable(feature = "std_misc",
-           reason = "hashing an hash maps may be altered")]
-pub struct RandomState {
-    k0: u64,
-    k1: u64,
-}
-
-#[unstable(feature = "std_misc",
-           reason = "hashing an hash maps may be altered")]
-impl RandomState {
-    /// Construct a new `RandomState` that is initialized with random keys.
-    #[inline]
-    #[allow(deprecated)]
-    pub fn new() -> RandomState {
-        let mut r = rand::thread_rng();
-        RandomState { k0: r.gen(), k1: r.gen() }
-    }
-}
-
-#[unstable(feature = "std_misc",
-           reason = "hashing an hash maps may be altered")]
-impl HashState for RandomState {
-    type Hasher = Hasher;
-    fn hasher(&self) -> Hasher {
-        Hasher { inner: SipHasher::new_with_keys(self.k0, self.k1) }
-    }
-}
-
-#[unstable(feature = "std_misc",
-           reason = "hashing an hash maps may be altered")]
-impl Default for RandomState {
-    #[inline]
-    fn default() -> RandomState {
-        RandomState::new()
-    }
-}
-
-/// A hasher implementation which is generated from `RandomState` instances.
-///
-/// This is the default hasher used in a `HashMap` to hash keys. Types do not
-/// typically declare an ability to explicitly hash into this particular type,
-/// but rather in a `H: hash::Writer` type parameter.
-#[unstable(feature = "std_misc",
-           reason = "hashing an hash maps may be altered")]
-pub struct Hasher { inner: SipHasher }
-
-impl hash::Writer for Hasher {
-    fn write(&mut self, data: &[u8]) {
-        hash::Writer::write(&mut self.inner, data)
-    }
-}
-
-impl hash::Hasher for Hasher {
-    type Output = u64;
-    fn reset(&mut self) { hash::Hasher::reset(&mut self.inner) }
-    fn finish(&self) -> u64 { self.inner.finish() }
-}
-
-#[cfg(test)]
-mod test_map {
-    use prelude::v1::*;
-
-    use super::HashMap;
-    use super::Entry::{Occupied, Vacant};
-    use iter::{range_inclusive, range_step_inclusive, repeat};
-    use cell::RefCell;
-    use rand::{weak_rng, Rng};
-
-    #[test]
-    fn test_create_capacity_zero() {
-        let mut m = HashMap::with_capacity(0);
-
-        assert!(m.insert(1, 1).is_none());
-
-        assert!(m.contains_key(&1));
-        assert!(!m.contains_key(&0));
-    }
-
-    #[test]
-    fn test_insert() {
-        let mut m = HashMap::new();
-        assert_eq!(m.len(), 0);
-        assert!(m.insert(1, 2).is_none());
-        assert_eq!(m.len(), 1);
-        assert!(m.insert(2, 4).is_none());
-        assert_eq!(m.len(), 2);
-        assert_eq!(*m.get(&1).unwrap(), 2);
-        assert_eq!(*m.get(&2).unwrap(), 4);
-    }
-
-    thread_local! { static DROP_VECTOR: RefCell<Vec<int>> = RefCell::new(Vec::new()) }
-
-    #[derive(Hash, PartialEq, Eq)]
-    struct Dropable {
-        k: usize
-    }
-
-    impl Dropable {
-        fn new(k: usize) -> Dropable {
-            DROP_VECTOR.with(|slot| {
-                slot.borrow_mut()[k] += 1;
-            });
-
-            Dropable { k: k }
-        }
-    }
-
-    impl Drop for Dropable {
-        fn drop(&mut self) {
-            DROP_VECTOR.with(|slot| {
-                slot.borrow_mut()[self.k] -= 1;
-            });
-        }
-    }
-
-    impl Clone for Dropable {
-        fn clone(&self) -> Dropable {
-            Dropable::new(self.k)
-        }
-    }
-
-    #[test]
-    fn test_drops() {
-        DROP_VECTOR.with(|slot| {
-            *slot.borrow_mut() = repeat(0).take(200).collect();
-        });
-
-        {
-            let mut m = HashMap::new();
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..200 {
-                    assert_eq!(v.borrow()[i], 0);
-                }
-            });
-
-            for i in 0..100 {
-                let d1 = Dropable::new(i);
-                let d2 = Dropable::new(i+100);
-                m.insert(d1, d2);
-            }
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..200 {
-                    assert_eq!(v.borrow()[i], 1);
-                }
-            });
-
-            for i in 0..50 {
-                let k = Dropable::new(i);
-                let v = m.remove(&k);
-
-                assert!(v.is_some());
-
-                DROP_VECTOR.with(|v| {
-                    assert_eq!(v.borrow()[i], 1);
-                    assert_eq!(v.borrow()[i+100], 1);
-                });
-            }
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..50 {
-                    assert_eq!(v.borrow()[i], 0);
-                    assert_eq!(v.borrow()[i+100], 0);
-                }
-
-                for i in 50..100 {
-                    assert_eq!(v.borrow()[i], 1);
-                    assert_eq!(v.borrow()[i+100], 1);
-                }
-            });
-        }
-
-        DROP_VECTOR.with(|v| {
-            for i in 0..200 {
-                assert_eq!(v.borrow()[i], 0);
-            }
-        });
-    }
-
-    #[test]
-    fn test_move_iter_drops() {
-        DROP_VECTOR.with(|v| {
-            *v.borrow_mut() = repeat(0).take(200).collect();
-        });
-
-        let hm = {
-            let mut hm = HashMap::new();
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..200 {
-                    assert_eq!(v.borrow()[i], 0);
-                }
-            });
-
-            for i in 0..100 {
-                let d1 = Dropable::new(i);
-                let d2 = Dropable::new(i+100);
-                hm.insert(d1, d2);
-            }
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..200 {
-                    assert_eq!(v.borrow()[i], 1);
-                }
-            });
-
-            hm
-        };
-
-        // By the way, ensure that cloning doesn't screw up the dropping.
-        drop(hm.clone());
-
-        {
-            let mut half = hm.into_iter().take(50);
-
-            DROP_VECTOR.with(|v| {
-                for i in 0..200 {
-                    assert_eq!(v.borrow()[i], 1);
-                }
-            });
-
-            for _ in half.by_ref() {}
-
-            DROP_VECTOR.with(|v| {
-                let nk = (0..100).filter(|&i| {
-                    v.borrow()[i] == 1
-                }).count();
-
-                let nv = (0..100).filter(|&i| {
-                    v.borrow()[i+100] == 1
-                }).count();
-
-                assert_eq!(nk, 50);
-                assert_eq!(nv, 50);
-            });
-        };
-
-        DROP_VECTOR.with(|v| {
-            for i in 0..200 {
-                assert_eq!(v.borrow()[i], 0);
-            }
-        });
-    }
-
-    #[test]
-    fn test_empty_pop() {
-        let mut m: HashMap<int, bool> = HashMap::new();
-        assert_eq!(m.remove(&0), None);
-    }
-
-    #[test]
-    fn test_lots_of_insertions() {
-        let mut m = HashMap::new();
-
-        // Try this a few times to make sure we never screw up the hashmap's
-        // internal state.
-        for _ in 0..10 {
-            assert!(m.is_empty());
-
-            for i in range_inclusive(1, 1000) {
-                assert!(m.insert(i, i).is_none());
-
-                for j in range_inclusive(1, i) {
-                    let r = m.get(&j);
-                    assert_eq!(r, Some(&j));
-                }
-
-                for j in range_inclusive(i+1, 1000) {
-                    let r = m.get(&j);
-                    assert_eq!(r, None);
-                }
-            }
-
-            for i in range_inclusive(1001, 2000) {
-                assert!(!m.contains_key(&i));
-            }
-
-            // remove forwards
-            for i in range_inclusive(1, 1000) {
-                assert!(m.remove(&i).is_some());
-
-                for j in range_inclusive(1, i) {
-                    assert!(!m.contains_key(&j));
-                }
-
-                for j in range_inclusive(i+1, 1000) {
-                    assert!(m.contains_key(&j));
-                }
-            }
-
-            for i in range_inclusive(1, 1000) {
-                assert!(!m.contains_key(&i));
-            }
-
-            for i in range_inclusive(1, 1000) {
-                assert!(m.insert(i, i).is_none());
-            }
-
-            // remove backwards
-            for i in range_step_inclusive(1000, 1, -1) {
-                assert!(m.remove(&i).is_some());
-
-                for j in range_inclusive(i, 1000) {
-                    assert!(!m.contains_key(&j));
-                }
-
-                for j in range_inclusive(1, i-1) {
-                    assert!(m.contains_key(&j));
-                }
-            }
-        }
-    }
-
-    #[test]
-    fn test_find_mut() {
-        let mut m = HashMap::new();
-        assert!(m.insert(1, 12).is_none());
-        assert!(m.insert(2, 8).is_none());
-        assert!(m.insert(5, 14).is_none());
-        let new = 100;
-        match m.get_mut(&5) {
-            None => panic!(), Some(x) => *x = new
-        }
-        assert_eq!(m.get(&5), Some(&new));
-    }
-
-    #[test]
-    fn test_insert_overwrite() {
-        let mut m = HashMap::new();
-        assert!(m.insert(1, 2).is_none());
-        assert_eq!(*m.get(&1).unwrap(), 2);
-        assert!(!m.insert(1, 3).is_none());
-        assert_eq!(*m.get(&1).unwrap(), 3);
-    }
-
-    #[test]
-    fn test_insert_conflicts() {
-        let mut m = HashMap::with_capacity(4);
-        assert!(m.insert(1, 2).is_none());
-        assert!(m.insert(5, 3).is_none());
-        assert!(m.insert(9, 4).is_none());
-        assert_eq!(*m.get(&9).unwrap(), 4);
-        assert_eq!(*m.get(&5).unwrap(), 3);
-        assert_eq!(*m.get(&1).unwrap(), 2);
-    }
-
-    #[test]
-    fn test_conflict_remove() {
-        let mut m = HashMap::with_capacity(4);
-        assert!(m.insert(1, 2).is_none());
-        assert_eq!(*m.get(&1).unwrap(), 2);
-        assert!(m.insert(5, 3).is_none());
-        assert_eq!(*m.get(&1).unwrap(), 2);
-        assert_eq!(*m.get(&5).unwrap(), 3);
-        assert!(m.insert(9, 4).is_none());
-        assert_eq!(*m.get(&1).unwrap(), 2);
-        assert_eq!(*m.get(&5).unwrap(), 3);
-        assert_eq!(*m.get(&9).unwrap(), 4);
-        assert!(m.remove(&1).is_some());
-        assert_eq!(*m.get(&9).unwrap(), 4);
-        assert_eq!(*m.get(&5).unwrap(), 3);
-    }
-
-    #[test]
-    fn test_is_empty() {
-        let mut m = HashMap::with_capacity(4);
-        assert!(m.insert(1, 2).is_none());
-        assert!(!m.is_empty());
-        assert!(m.remove(&1).is_some());
-        assert!(m.is_empty());
-    }
-
-    #[test]
-    fn test_pop() {
-        let mut m = HashMap::new();
-        m.insert(1, 2);
-        assert_eq!(m.remove(&1), Some(2));
-        assert_eq!(m.remove(&1), None);
-    }
-
-    #[test]
-    fn test_iterate() {
-        let mut m = HashMap::with_capacity(4);
-        for i in 0..32 {
-            assert!(m.insert(i, i*2).is_none());
-        }
-        assert_eq!(m.len(), 32);
-
-        let mut observed: u32 = 0;
-
-        for (k, v) in &m {
-            assert_eq!(*v, *k * 2);
-            observed |= 1 << *k;
-        }
-        assert_eq!(observed, 0xFFFF_FFFF);
-    }
-
-    #[test]
-    fn test_keys() {
-        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
-        let map: HashMap<_, _> = vec.into_iter().collect();
-        let keys: Vec<_> = map.keys().cloned().collect();
-        assert_eq!(keys.len(), 3);
-        assert!(keys.contains(&1));
-        assert!(keys.contains(&2));
-        assert!(keys.contains(&3));
-    }
-
-    #[test]
-    fn test_values() {
-        let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
-        let map: HashMap<_, _> = vec.into_iter().collect();
-        let values: Vec<_> = map.values().cloned().collect();
-        assert_eq!(values.len(), 3);
-        assert!(values.contains(&'a'));
-        assert!(values.contains(&'b'));
-        assert!(values.contains(&'c'));
-    }
-
-    #[test]
-    fn test_find() {
-        let mut m = HashMap::new();
-        assert!(m.get(&1).is_none());
-        m.insert(1, 2);
-        match m.get(&1) {
-            None => panic!(),
-            Some(v) => assert_eq!(*v, 2)
-        }
-    }
-
-    #[test]
-    fn test_eq() {
-        let mut m1 = HashMap::new();
-        m1.insert(1, 2);
-        m1.insert(2, 3);
-        m1.insert(3, 4);
-
-        let mut m2 = HashMap::new();
-        m2.insert(1, 2);
-        m2.insert(2, 3);
-
-        assert!(m1 != m2);
-
-        m2.insert(3, 4);
-
-        assert_eq!(m1, m2);
-    }
-
-    #[test]
-    fn test_show() {
-        let mut map = HashMap::new();
-        let empty: HashMap<i32, i32> = HashMap::new();
-
-        map.insert(1, 2);
-        map.insert(3, 4);
-
-        let map_str = format!("{:?}", map);
-
-        assert!(map_str == "HashMap {1: 2, 3: 4}" ||
-                map_str == "HashMap {3: 4, 1: 2}");
-        assert_eq!(format!("{:?}", empty), "HashMap {}");
-    }
-
-    #[test]
-    fn test_expand() {
-        let mut m = HashMap::new();
-
-        assert_eq!(m.len(), 0);
-        assert!(m.is_empty());
-
-        let mut i = 0;
-        let old_cap = m.table.capacity();
-        while old_cap == m.table.capacity() {
-            m.insert(i, i);
-            i += 1;
-        }
-
-        assert_eq!(m.len(), i);
-        assert!(!m.is_empty());
-    }
-
-    #[test]
-    fn test_behavior_resize_policy() {
-        let mut m = HashMap::new();
-
-        assert_eq!(m.len(), 0);
-        assert_eq!(m.table.capacity(), 0);
-        assert!(m.is_empty());
-
-        m.insert(0, 0);
-        m.remove(&0);
-        assert!(m.is_empty());
-        let initial_cap = m.table.capacity();
-        m.reserve(initial_cap);
-        let cap = m.table.capacity();
-
-        assert_eq!(cap, initial_cap * 2);
-
-        let mut i = 0;
-        for _ in 0..cap * 3 / 4 {
-            m.insert(i, i);
-            i += 1;
-        }
-        // three quarters full
-
-        assert_eq!(m.len(), i);
-        assert_eq!(m.table.capacity(), cap);
-
-        for _ in 0..cap / 4 {
-            m.insert(i, i);
-            i += 1;
-        }
-        // half full
-
-        let new_cap = m.table.capacity();
-        assert_eq!(new_cap, cap * 2);
-
-        for _ in 0..cap / 2 - 1 {
-            i -= 1;
-            m.remove(&i);
-            assert_eq!(m.table.capacity(), new_cap);
-        }
-        // A little more than one quarter full.
-        m.shrink_to_fit();
-        assert_eq!(m.table.capacity(), cap);
-        // again, a little more than half full
-        for _ in 0..cap / 2 - 1 {
-            i -= 1;
-            m.remove(&i);
-        }
-        m.shrink_to_fit();
-
-        assert_eq!(m.len(), i);
-        assert!(!m.is_empty());
-        assert_eq!(m.table.capacity(), initial_cap);
-    }
-
-    #[test]
-    fn test_reserve_shrink_to_fit() {
-        let mut m = HashMap::new();
-        m.insert(0, 0);
-        m.remove(&0);
-        assert!(m.capacity() >= m.len());
-        for i in 0..128 {
-            m.insert(i, i);
-        }
-        m.reserve(256);
-
-        let usable_cap = m.capacity();
-        for i in 128..(128 + 256) {
-            m.insert(i, i);
-            assert_eq!(m.capacity(), usable_cap);
-        }
-
-        for i in 100..(128 + 256) {
-            assert_eq!(m.remove(&i), Some(i));
-        }
-        m.shrink_to_fit();
-
-        assert_eq!(m.len(), 100);
-        assert!(!m.is_empty());
-        assert!(m.capacity() >= m.len());
-
-        for i in 0..100 {
-            assert_eq!(m.remove(&i), Some(i));
-        }
-        m.shrink_to_fit();
-        m.insert(0, 0);
-
-        assert_eq!(m.len(), 1);
-        assert!(m.capacity() >= m.len());
-        assert_eq!(m.remove(&0), Some(0));
-    }
-
-    #[test]
-    fn test_from_iter() {
-        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
-
-        let map: HashMap<_, _> = xs.iter().cloned().collect();
-
-        for &(k, v) in &xs {
-            assert_eq!(map.get(&k), Some(&v));
-        }
-    }
-
-    #[test]
-    fn test_size_hint() {
-        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
-
-        let map: HashMap<_, _>  = xs.iter().cloned().collect();
-
-        let mut iter = map.iter();
-
-        for _ in iter.by_ref().take(3) {}
-
-        assert_eq!(iter.size_hint(), (3, Some(3)));
-    }
-
-    #[test]
-    fn test_iter_len() {
-        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
-
-        let map: HashMap<_, _>  = xs.iter().cloned().collect();
-
-        let mut iter = map.iter();
-
-        for _ in iter.by_ref().take(3) {}
-
-        assert_eq!(iter.len(), 3);
-    }
-
-    #[test]
-    fn test_mut_size_hint() {
-        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
-
-        let mut map: HashMap<_, _>  = xs.iter().cloned().collect();
-
-        let mut iter = map.iter_mut();
-
-        for _ in iter.by_ref().take(3) {}
-
-        assert_eq!(iter.size_hint(), (3, Some(3)));
-    }
-
-    #[test]
-    fn test_iter_mut_len() {
-        let xs = [(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
-
-        let mut map: HashMap<_, _>  = xs.iter().cloned().collect();
-
-        let mut iter = map.iter_mut();
-
-        for _ in iter.by_ref().take(3) {}
-
-        assert_eq!(iter.len(), 3);
-    }
-
-    #[test]
-    fn test_index() {
-        let mut map = HashMap::new();
-
-        map.insert(1, 2);
-        map.insert(2, 1);
-        map.insert(3, 4);
-
-        assert_eq!(map[2], 1);
-    }
-
-    #[test]
-    #[should_fail]
-    fn test_index_nonexistent() {
-        let mut map = HashMap::new();
-
-        map.insert(1, 2);
-        map.insert(2, 1);
-        map.insert(3, 4);
-
-        map[4];
-    }
-
-    #[test]
-    fn test_entry(){
-        let xs = [(1, 10), (2, 20), (3, 30), (4, 40), (5, 50), (6, 60)];
-
-        let mut map: HashMap<_, _> = xs.iter().cloned().collect();
-
-        // Existing key (insert)
-        match map.entry(1) {
-            Vacant(_) => unreachable!(),
-            Occupied(mut view) => {
-                assert_eq!(view.get(), &10);
-                assert_eq!(view.insert(100), 10);
-            }
-        }
-        assert_eq!(map.get(&1).unwrap(), &100);
-        assert_eq!(map.len(), 6);
-
-
-        // Existing key (update)
-        match map.entry(2) {
-            Vacant(_) => unreachable!(),
-            Occupied(mut view) => {
-                let v = view.get_mut();
-                let new_v = (*v) * 10;
-                *v = new_v;
-            }
-        }
-        assert_eq!(map.get(&2).unwrap(), &200);
-        assert_eq!(map.len(), 6);
-
-        // Existing key (take)
-        match map.entry(3) {
-            Vacant(_) => unreachable!(),
-            Occupied(view) => {
-                assert_eq!(view.remove(), 30);
-            }
-        }
-        assert_eq!(map.get(&3), None);
-        assert_eq!(map.len(), 5);
-
-
-        // Inexistent key (insert)
-        match map.entry(10) {
-            Occupied(_) => unreachable!(),
-            Vacant(view) => {
-                assert_eq!(*view.insert(1000), 1000);
-            }
-        }
-        assert_eq!(map.get(&10).unwrap(), &1000);
-        assert_eq!(map.len(), 6);
-    }
-
-    #[test]
-    fn test_entry_take_doesnt_corrupt() {
-        // Test for #19292
-        fn check(m: &HashMap<isize, ()>) {
-            for k in m.keys() {
-                assert!(m.contains_key(k),
-                        "{} is in keys() but not in the map?", k);
-            }
-        }
-
-        let mut m = HashMap::new();
-        let mut rng = weak_rng();
-
-        // Populate the map with some items.
-        for _ in 0..50 {
-            let x = rng.gen_range(-10, 10);
-            m.insert(x, ());
-        }
-
-        for i in 0..1000 {
-            let x = rng.gen_range(-10, 10);
-            match m.entry(x) {
-                Vacant(_) => {},
-                Occupied(e) => {
-                    println!("{}: remove {}", i, x);
-                    e.remove();
-                },
-            }
-
-            check(&m);
-        }
-    }
-}
diff --git a/src/libstd/collections/hash/mod.rs b/src/libstd/collections/hash/mod.rs
index 39c1458b720..47e300af269 100644
--- a/src/libstd/collections/hash/mod.rs
+++ b/src/libstd/collections/hash/mod.rs
@@ -12,14 +12,6 @@
 
 mod bench;
 mod table;
-#[cfg(stage0)]
-#[path = "map_stage0.rs"]
 pub mod map;
-#[cfg(not(stage0))]
-pub mod map;
-#[cfg(stage0)]
-#[path = "set_stage0.rs"]
-pub mod set;
-#[cfg(not(stage0))]
 pub mod set;
 pub mod state;
diff --git a/src/libstd/collections/hash/set_stage0.rs b/src/libstd/collections/hash/set_stage0.rs
deleted file mode 100644
index 68c9e02d8ad..00000000000
--- a/src/libstd/collections/hash/set_stage0.rs
+++ /dev/null
@@ -1,1252 +0,0 @@
-// Copyright 2014 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.
-//
-// ignore-lexer-test FIXME #15883
-
-use borrow::Borrow;
-use clone::Clone;
-use cmp::{Eq, PartialEq};
-use core::marker::Sized;
-use default::Default;
-use fmt::Debug;
-use fmt;
-use hash::{self, Hash};
-use iter::{
-    Iterator, IntoIterator, ExactSizeIterator, IteratorExt, FromIterator, Map, Chain, Extend,
-};
-use ops::{BitOr, BitAnd, BitXor, Sub};
-use option::Option::{Some, None, self};
-
-use super::map::{self, HashMap, Keys, INITIAL_CAPACITY, RandomState, Hasher};
-use super::state::HashState;
-
-// Future Optimization (FIXME!)
-// =============================
-//
-// Iteration over zero sized values is a noop. There is no need
-// for `bucket.val` in the case of HashSet. I suppose we would need HKT
-// to get rid of it properly.
-
-/// An implementation of a hash set using the underlying representation of a
-/// HashMap where the value is (). As with the `HashMap` type, a `HashSet`
-/// requires that the elements implement the `Eq` and `Hash` traits.
-///
-/// # Example
-///
-/// ```
-/// use std::collections::HashSet;
-/// // Type inference lets us omit an explicit type signature (which
-/// // would be `HashSet<&str>` in this example).
-/// let mut books = HashSet::new();
-///
-/// // Add some books.
-/// books.insert("A Dance With Dragons");
-/// books.insert("To Kill a Mockingbird");
-/// books.insert("The Odyssey");
-/// books.insert("The Great Gatsby");
-///
-/// // Check for a specific one.
-/// if !books.contains(&("The Winds of Winter")) {
-///     println!("We have {} books, but The Winds of Winter ain't one.",
-///              books.len());
-/// }
-///
-/// // Remove a book.
-/// books.remove(&"The Odyssey");
-///
-/// // Iterate over everything.
-/// for book in books.iter() {
-///     println!("{}", *book);
-/// }
-/// ```
-///
-/// The easiest way to use `HashSet` with a custom type is to derive
-/// `Eq` and `Hash`. We must also derive `PartialEq`, this will in the
-/// future be implied by `Eq`.
-///
-/// ```
-/// use std::collections::HashSet;
-/// #[derive(Hash, Eq, PartialEq, Debug)]
-/// struct Viking<'a> {
-///     name: &'a str,
-///     power: usize,
-/// }
-///
-/// let mut vikings = HashSet::new();
-///
-/// vikings.insert(Viking { name: "Einar", power: 9 });
-/// vikings.insert(Viking { name: "Einar", power: 9 });
-/// vikings.insert(Viking { name: "Olaf", power: 4 });
-/// vikings.insert(Viking { name: "Harald", power: 8 });
-///
-/// // Use derived implementation to print the vikings.
-/// for x in vikings.iter() {
-///     println!("{:?}", x);
-/// }
-/// ```
-#[derive(Clone)]
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct HashSet<T, S = RandomState> {
-    map: HashMap<T, (), S>
-}
-
-impl<T: Hash<Hasher> + Eq> HashSet<T, RandomState> {
-    /// Create an empty HashSet.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let mut set: HashSet<int> = HashSet::new();
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn new() -> HashSet<T, RandomState> {
-        HashSet::with_capacity(INITIAL_CAPACITY)
-    }
-
-    /// Create an empty HashSet with space for at least `n` elements in
-    /// the hash table.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let mut set: HashSet<int> = HashSet::with_capacity(10);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn with_capacity(capacity: usize) -> HashSet<T, RandomState> {
-        HashSet { map: HashMap::with_capacity(capacity) }
-    }
-}
-
-impl<T, S, H> HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    /// Creates a new empty hash set which will use the given hasher to hash
-    /// keys.
-    ///
-    /// The hash set is also created with the default initial capacity.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// use std::collections::hash_map::RandomState;
-    ///
-    /// let s = RandomState::new();
-    /// let mut set = HashSet::with_hash_state(s);
-    /// set.insert(2);
-    /// ```
-    #[inline]
-    #[unstable(feature = "std_misc", reason = "hasher stuff is unclear")]
-    pub fn with_hash_state(hash_state: S) -> HashSet<T, S> {
-        HashSet::with_capacity_and_hash_state(INITIAL_CAPACITY, hash_state)
-    }
-
-    /// Create an empty HashSet with space for at least `capacity`
-    /// elements in the hash table, using `hasher` to hash the keys.
-    ///
-    /// Warning: `hasher` is normally randomly generated, and
-    /// is designed to allow `HashSet`s to be resistant to attacks that
-    /// cause many collisions and very poor performance. Setting it
-    /// manually using this function can expose a DoS attack vector.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// use std::collections::hash_map::RandomState;
-    ///
-    /// let s = RandomState::new();
-    /// let mut set = HashSet::with_capacity_and_hash_state(10, s);
-    /// set.insert(1);
-    /// ```
-    #[inline]
-    #[unstable(feature = "std_misc", reason = "hasher stuff is unclear")]
-    pub fn with_capacity_and_hash_state(capacity: usize, hash_state: S)
-                                        -> HashSet<T, S> {
-        HashSet {
-            map: HashMap::with_capacity_and_hash_state(capacity, hash_state),
-        }
-    }
-
-    /// Returns the number of elements the set can hold without reallocating.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let set: HashSet<int> = HashSet::with_capacity(100);
-    /// assert!(set.capacity() >= 100);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn capacity(&self) -> usize {
-        self.map.capacity()
-    }
-
-    /// Reserves capacity for at least `additional` more elements to be inserted
-    /// in the `HashSet`. The collection may reserve more space to avoid
-    /// frequent reallocations.
-    ///
-    /// # Panics
-    ///
-    /// Panics if the new allocation size overflows `usize`.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let mut set: HashSet<int> = HashSet::new();
-    /// set.reserve(10);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn reserve(&mut self, additional: usize) {
-        self.map.reserve(additional)
-    }
-
-    /// Shrinks the capacity of the set as much as possible. It will drop
-    /// down as much as possible while maintaining the internal rules
-    /// and possibly leaving some space in accordance with the resize policy.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut set: HashSet<int> = HashSet::with_capacity(100);
-    /// set.insert(1);
-    /// set.insert(2);
-    /// assert!(set.capacity() >= 100);
-    /// set.shrink_to_fit();
-    /// assert!(set.capacity() >= 2);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn shrink_to_fit(&mut self) {
-        self.map.shrink_to_fit()
-    }
-
-    /// An iterator visiting all elements in arbitrary order.
-    /// Iterator element type is &'a T.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let mut set = HashSet::new();
-    /// set.insert("a");
-    /// set.insert("b");
-    ///
-    /// // Will print in an arbitrary order.
-    /// for x in set.iter() {
-    ///     println!("{}", x);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn iter(&self) -> Iter<T> {
-        Iter { iter: self.map.keys() }
-    }
-
-    /// Creates a consuming iterator, that is, one that moves each value out
-    /// of the set in arbitrary order. The set cannot be used after calling
-    /// this.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let mut set = HashSet::new();
-    /// set.insert("a".to_string());
-    /// set.insert("b".to_string());
-    ///
-    /// // Not possible to collect to a Vec<String> with a regular `.iter()`.
-    /// let v: Vec<String> = set.into_iter().collect();
-    ///
-    /// // Will print in an arbitrary order.
-    /// for x in v.iter() {
-    ///     println!("{}", x);
-    /// }
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn into_iter(self) -> IntoIter<T> {
-        fn first<A, B>((a, _): (A, B)) -> A { a }
-        let first: fn((T, ())) -> T = first;
-
-        IntoIter { iter: self.map.into_iter().map(first) }
-    }
-
-    /// Visit the values representing the difference.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let a: HashSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
-    /// let b: HashSet<int> = [4, 2, 3, 4].iter().map(|&x| x).collect();
-    ///
-    /// // Can be seen as `a - b`.
-    /// for x in a.difference(&b) {
-    ///     println!("{}", x); // Print 1
-    /// }
-    ///
-    /// let diff: HashSet<int> = a.difference(&b).map(|&x| x).collect();
-    /// assert_eq!(diff, [1].iter().map(|&x| x).collect());
-    ///
-    /// // Note that difference is not symmetric,
-    /// // and `b - a` means something else:
-    /// let diff: HashSet<int> = b.difference(&a).map(|&x| x).collect();
-    /// assert_eq!(diff, [4].iter().map(|&x| x).collect());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn difference<'a>(&'a self, other: &'a HashSet<T, S>) -> Difference<'a, T, S> {
-        Difference {
-            iter: self.iter(),
-            other: other,
-        }
-    }
-
-    /// Visit the values representing the symmetric difference.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let a: HashSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
-    /// let b: HashSet<int> = [4, 2, 3, 4].iter().map(|&x| x).collect();
-    ///
-    /// // Print 1, 4 in arbitrary order.
-    /// for x in a.symmetric_difference(&b) {
-    ///     println!("{}", x);
-    /// }
-    ///
-    /// let diff1: HashSet<int> = a.symmetric_difference(&b).map(|&x| x).collect();
-    /// let diff2: HashSet<int> = b.symmetric_difference(&a).map(|&x| x).collect();
-    ///
-    /// assert_eq!(diff1, diff2);
-    /// assert_eq!(diff1, [1, 4].iter().map(|&x| x).collect());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn symmetric_difference<'a>(&'a self, other: &'a HashSet<T, S>)
-        -> SymmetricDifference<'a, T, S> {
-        SymmetricDifference { iter: self.difference(other).chain(other.difference(self)) }
-    }
-
-    /// Visit the values representing the intersection.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let a: HashSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
-    /// let b: HashSet<int> = [4, 2, 3, 4].iter().map(|&x| x).collect();
-    ///
-    /// // Print 2, 3 in arbitrary order.
-    /// for x in a.intersection(&b) {
-    ///     println!("{}", x);
-    /// }
-    ///
-    /// let diff: HashSet<int> = a.intersection(&b).map(|&x| x).collect();
-    /// assert_eq!(diff, [2, 3].iter().map(|&x| x).collect());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn intersection<'a>(&'a self, other: &'a HashSet<T, S>) -> Intersection<'a, T, S> {
-        Intersection {
-            iter: self.iter(),
-            other: other,
-        }
-    }
-
-    /// Visit the values representing the union.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    /// let a: HashSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
-    /// let b: HashSet<int> = [4, 2, 3, 4].iter().map(|&x| x).collect();
-    ///
-    /// // Print 1, 2, 3, 4 in arbitrary order.
-    /// for x in a.union(&b) {
-    ///     println!("{}", x);
-    /// }
-    ///
-    /// let diff: HashSet<int> = a.union(&b).map(|&x| x).collect();
-    /// assert_eq!(diff, [1, 2, 3, 4].iter().map(|&x| x).collect());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn union<'a>(&'a self, other: &'a HashSet<T, S>) -> Union<'a, T, S> {
-        Union { iter: self.iter().chain(other.difference(self)) }
-    }
-
-    /// Return the number of elements in the set
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut v = HashSet::new();
-    /// assert_eq!(v.len(), 0);
-    /// v.insert(1);
-    /// assert_eq!(v.len(), 1);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn len(&self) -> usize { self.map.len() }
-
-    /// Returns true if the set contains no elements
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut v = HashSet::new();
-    /// assert!(v.is_empty());
-    /// v.insert(1);
-    /// assert!(!v.is_empty());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn is_empty(&self) -> bool { self.map.len() == 0 }
-
-    /// Clears the set, returning all elements in an iterator.
-    #[inline]
-    #[unstable(feature = "std_misc",
-               reason = "matches collection reform specification, waiting for dust to settle")]
-    pub fn drain(&mut self) -> Drain<T> {
-        fn first<A, B>((a, _): (A, B)) -> A { a }
-        let first: fn((T, ())) -> T = first; // coerce to fn pointer
-
-        Drain { iter: self.map.drain().map(first) }
-    }
-
-    /// Clears the set, removing all values.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut v = HashSet::new();
-    /// v.insert(1);
-    /// v.clear();
-    /// assert!(v.is_empty());
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn clear(&mut self) { self.map.clear() }
-
-    /// Returns `true` if the set contains a value.
-    ///
-    /// The value may be any borrowed form of the set's value type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the value type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let set: HashSet<_> = [1, 2, 3].iter().cloned().collect();
-    /// assert_eq!(set.contains(&1), true);
-    /// assert_eq!(set.contains(&4), false);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool
-        where T: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        self.map.contains_key(value)
-    }
-
-    /// Returns `true` if the set has no elements in common with `other`.
-    /// This is equivalent to checking for an empty intersection.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let a: HashSet<_> = [1, 2, 3].iter().cloned().collect();
-    /// let mut b = HashSet::new();
-    ///
-    /// assert_eq!(a.is_disjoint(&b), true);
-    /// b.insert(4);
-    /// assert_eq!(a.is_disjoint(&b), true);
-    /// b.insert(1);
-    /// assert_eq!(a.is_disjoint(&b), false);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn is_disjoint(&self, other: &HashSet<T, S>) -> bool {
-        self.iter().all(|v| !other.contains(v))
-    }
-
-    /// Returns `true` if the set is a subset of another.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let sup: HashSet<_> = [1, 2, 3].iter().cloned().collect();
-    /// let mut set = HashSet::new();
-    ///
-    /// assert_eq!(set.is_subset(&sup), true);
-    /// set.insert(2);
-    /// assert_eq!(set.is_subset(&sup), true);
-    /// set.insert(4);
-    /// assert_eq!(set.is_subset(&sup), false);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn is_subset(&self, other: &HashSet<T, S>) -> bool {
-        self.iter().all(|v| other.contains(v))
-    }
-
-    /// Returns `true` if the set is a superset of another.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let sub: HashSet<_> = [1, 2].iter().cloned().collect();
-    /// let mut set = HashSet::new();
-    ///
-    /// assert_eq!(set.is_superset(&sub), false);
-    ///
-    /// set.insert(0);
-    /// set.insert(1);
-    /// assert_eq!(set.is_superset(&sub), false);
-    ///
-    /// set.insert(2);
-    /// assert_eq!(set.is_superset(&sub), true);
-    /// ```
-    #[inline]
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn is_superset(&self, other: &HashSet<T, S>) -> bool {
-        other.is_subset(self)
-    }
-
-    /// Adds a value to the set. Returns `true` if the value was not already
-    /// present in the set.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut set = HashSet::new();
-    ///
-    /// assert_eq!(set.insert(2), true);
-    /// assert_eq!(set.insert(2), false);
-    /// assert_eq!(set.len(), 1);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn insert(&mut self, value: T) -> bool { self.map.insert(value, ()).is_none() }
-
-    /// Removes a value from the set. Returns `true` if the value was
-    /// present in the set.
-    ///
-    /// The value may be any borrowed form of the set's value type, but
-    /// `Hash` and `Eq` on the borrowed form *must* match those for
-    /// the value type.
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let mut set = HashSet::new();
-    ///
-    /// set.insert(2);
-    /// assert_eq!(set.remove(&2), true);
-    /// assert_eq!(set.remove(&2), false);
-    /// ```
-    #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool
-        where T: Borrow<Q>, Q: Hash<H> + Eq
-    {
-        self.map.remove(value).is_some()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> PartialEq for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn eq(&self, other: &HashSet<T, S>) -> bool {
-        if self.len() != other.len() { return false; }
-
-        self.iter().all(|key| other.contains(key))
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Eq for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> fmt::Debug for HashSet<T, S>
-    where T: Eq + Hash<H> + fmt::Debug,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(f, "HashSet {{"));
-
-        for (i, x) in self.iter().enumerate() {
-            if i != 0 { try!(write!(f, ", ")); }
-            try!(write!(f, "{:?}", *x));
-        }
-
-        write!(f, "}}")
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> FromIterator<T> for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    fn from_iter<I: IntoIterator<Item=T>>(iter: I) -> HashSet<T, S> {
-        let iter = iter.into_iter();
-        let lower = iter.size_hint().0;
-        let mut set = HashSet::with_capacity_and_hash_state(lower, Default::default());
-        set.extend(iter);
-        set
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Extend<T> for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    fn extend<I: IntoIterator<Item=T>>(&mut self, iter: I) {
-        for k in iter {
-            self.insert(k);
-        }
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<T, S, H> Default for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    #[stable(feature = "rust1", since = "1.0.0")]
-    fn default() -> HashSet<T, S> {
-        HashSet::with_hash_state(Default::default())
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitOr<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    type Output = HashSet<T, S>;
-
-    /// Returns the union of `self` and `rhs` as a new `HashSet<T, S>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
-    /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
-    ///
-    /// let set = &a | &b;
-    ///
-    /// let mut i = 0;
-    /// let expected = [1, 2, 3, 4, 5];
-    /// for x in set.iter() {
-    ///     assert!(expected.contains(x));
-    ///     i += 1;
-    /// }
-    /// assert_eq!(i, expected.len());
-    /// ```
-    fn bitor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
-        self.union(rhs).cloned().collect()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitAnd<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    type Output = HashSet<T, S>;
-
-    /// Returns the intersection of `self` and `rhs` as a new `HashSet<T, S>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
-    /// let b: HashSet<_> = vec![2, 3, 4].into_iter().collect();
-    ///
-    /// let set = &a & &b;
-    ///
-    /// let mut i = 0;
-    /// let expected = [2, 3];
-    /// for x in set.iter() {
-    ///     assert!(expected.contains(x));
-    ///     i += 1;
-    /// }
-    /// assert_eq!(i, expected.len());
-    /// ```
-    fn bitand(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
-        self.intersection(rhs).cloned().collect()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> BitXor<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    type Output = HashSet<T, S>;
-
-    /// Returns the symmetric difference of `self` and `rhs` as a new `HashSet<T, S>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
-    /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
-    ///
-    /// let set = &a ^ &b;
-    ///
-    /// let mut i = 0;
-    /// let expected = [1, 2, 4, 5];
-    /// for x in set.iter() {
-    ///     assert!(expected.contains(x));
-    ///     i += 1;
-    /// }
-    /// assert_eq!(i, expected.len());
-    /// ```
-    fn bitxor(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
-        self.symmetric_difference(rhs).cloned().collect()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, 'b, T, S, H> Sub<&'b HashSet<T, S>> for &'a HashSet<T, S>
-    where T: Eq + Hash<H> + Clone,
-          S: HashState<Hasher=H> + Default,
-          H: hash::Hasher<Output=u64>
-{
-    type Output = HashSet<T, S>;
-
-    /// Returns the difference of `self` and `rhs` as a new `HashSet<T, S>`.
-    ///
-    /// # Examples
-    ///
-    /// ```
-    /// use std::collections::HashSet;
-    ///
-    /// let a: HashSet<_> = vec![1, 2, 3].into_iter().collect();
-    /// let b: HashSet<_> = vec![3, 4, 5].into_iter().collect();
-    ///
-    /// let set = &a - &b;
-    ///
-    /// let mut i = 0;
-    /// let expected = [1, 2];
-    /// for x in set.iter() {
-    ///     assert!(expected.contains(x));
-    ///     i += 1;
-    /// }
-    /// assert_eq!(i, expected.len());
-    /// ```
-    fn sub(self, rhs: &HashSet<T, S>) -> HashSet<T, S> {
-        self.difference(rhs).cloned().collect()
-    }
-}
-
-/// HashSet iterator
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Iter<'a, K: 'a> {
-    iter: Keys<'a, K, ()>
-}
-
-/// HashSet move iterator
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct IntoIter<K> {
-    iter: Map<map::IntoIter<K, ()>, fn((K, ())) -> K>
-}
-
-/// HashSet drain iterator
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Drain<'a, K: 'a> {
-    iter: Map<map::Drain<'a, K, ()>, fn((K, ())) -> K>,
-}
-
-/// Intersection iterator
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Intersection<'a, T: 'a, S: 'a> {
-    // iterator of the first set
-    iter: Iter<'a, T>,
-    // the second set
-    other: &'a HashSet<T, S>,
-}
-
-/// Difference iterator
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Difference<'a, T: 'a, S: 'a> {
-    // iterator of the first set
-    iter: Iter<'a, T>,
-    // the second set
-    other: &'a HashSet<T, S>,
-}
-
-/// Symmetric difference iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct SymmetricDifference<'a, T: 'a, S: 'a> {
-    iter: Chain<Difference<'a, T, S>, Difference<'a, T, S>>
-}
-
-/// Set union iterator.
-#[stable(feature = "rust1", since = "1.0.0")]
-pub struct Union<'a, T: 'a, S: 'a> {
-    iter: Chain<Iter<'a, T>, Difference<'a, T, S>>
-}
-
-impl<'a, T, S, H> IntoIterator for &'a HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = &'a T;
-    type IntoIter = Iter<'a, T>;
-
-    fn into_iter(self) -> Iter<'a, T> {
-        self.iter()
-    }
-}
-
-impl<T, S, H> IntoIterator for HashSet<T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = T;
-    type IntoIter = IntoIter<T>;
-
-    fn into_iter(self) -> IntoIter<T> {
-        self.into_iter()
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> Iterator for Iter<'a, K> {
-    type Item = &'a K;
-
-    fn next(&mut self) -> Option<&'a K> { self.iter.next() }
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Iter<'a, K> {
-    fn len(&self) -> usize { self.iter.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K> Iterator for IntoIter<K> {
-    type Item = K;
-
-    fn next(&mut self) -> Option<K> { self.iter.next() }
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<K> ExactSizeIterator for IntoIter<K> {
-    fn len(&self) -> usize { self.iter.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> Iterator for Drain<'a, K> {
-    type Item = K;
-
-    fn next(&mut self) -> Option<K> { self.iter.next() }
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-}
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, K> ExactSizeIterator for Drain<'a, K> {
-    fn len(&self) -> usize { self.iter.len() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Intersection<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = &'a T;
-
-    fn next(&mut self) -> Option<&'a T> {
-        loop {
-            match self.iter.next() {
-                None => return None,
-                Some(elt) => if self.other.contains(elt) {
-                    return Some(elt)
-                },
-            }
-        }
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Difference<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = &'a T;
-
-    fn next(&mut self) -> Option<&'a T> {
-        loop {
-            match self.iter.next() {
-                None => return None,
-                Some(elt) => if !self.other.contains(elt) {
-                    return Some(elt)
-                },
-            }
-        }
-    }
-
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (_, upper) = self.iter.size_hint();
-        (0, upper)
-    }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for SymmetricDifference<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = &'a T;
-
-    fn next(&mut self) -> Option<&'a T> { self.iter.next() }
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-}
-
-#[stable(feature = "rust1", since = "1.0.0")]
-impl<'a, T, S, H> Iterator for Union<'a, T, S>
-    where T: Eq + Hash<H>,
-          S: HashState<Hasher=H>,
-          H: hash::Hasher<Output=u64>
-{
-    type Item = &'a T;
-
-    fn next(&mut self) -> Option<&'a T> { self.iter.next() }
-    fn size_hint(&self) -> (usize, Option<usize>) { self.iter.size_hint() }
-}
-
-#[cfg(test)]
-mod test_set {
-    use prelude::v1::*;
-
-    use super::HashSet;
-
-    #[test]
-    fn test_disjoint() {
-        let mut xs = HashSet::new();
-        let mut ys = HashSet::new();
-        assert!(xs.is_disjoint(&ys));
-        assert!(ys.is_disjoint(&xs));
-        assert!(xs.insert(5));
-        assert!(ys.insert(11));
-        assert!(xs.is_disjoint(&ys));
-        assert!(ys.is_disjoint(&xs));
-        assert!(xs.insert(7));
-        assert!(xs.insert(19));
-        assert!(xs.insert(4));
-        assert!(ys.insert(2));
-        assert!(ys.insert(-11));
-        assert!(xs.is_disjoint(&ys));
-        assert!(ys.is_disjoint(&xs));
-        assert!(ys.insert(7));
-        assert!(!xs.is_disjoint(&ys));
-        assert!(!ys.is_disjoint(&xs));
-    }
-
-    #[test]
-    fn test_subset_and_superset() {
-        let mut a = HashSet::new();
-        assert!(a.insert(0));
-        assert!(a.insert(5));
-        assert!(a.insert(11));
-        assert!(a.insert(7));
-
-        let mut b = HashSet::new();
-        assert!(b.insert(0));
-        assert!(b.insert(7));
-        assert!(b.insert(19));
-        assert!(b.insert(250));
-        assert!(b.insert(11));
-        assert!(b.insert(200));
-
-        assert!(!a.is_subset(&b));
-        assert!(!a.is_superset(&b));
-        assert!(!b.is_subset(&a));
-        assert!(!b.is_superset(&a));
-
-        assert!(b.insert(5));
-
-        assert!(a.is_subset(&b));
-        assert!(!a.is_superset(&b));
-        assert!(!b.is_subset(&a));
-        assert!(b.is_superset(&a));
-    }
-
-    #[test]
-    fn test_iterate() {
-        let mut a = HashSet::new();
-        for i in 0..32 {
-            assert!(a.insert(i));
-        }
-        let mut observed: u32 = 0;
-        for k in &a {
-            observed |= 1 << *k;
-        }
-        assert_eq!(observed, 0xFFFF_FFFF);
-    }
-
-    #[test]
-    fn test_intersection() {
-        let mut a = HashSet::new();
-        let mut b = HashSet::new();
-
-        assert!(a.insert(11));
-        assert!(a.insert(1));
-        assert!(a.insert(3));
-        assert!(a.insert(77));
-        assert!(a.insert(103));
-        assert!(a.insert(5));
-        assert!(a.insert(-5));
-
-        assert!(b.insert(2));
-        assert!(b.insert(11));
-        assert!(b.insert(77));
-        assert!(b.insert(-9));
-        assert!(b.insert(-42));
-        assert!(b.insert(5));
-        assert!(b.insert(3));
-
-        let mut i = 0;
-        let expected = [3, 5, 11, 77];
-        for x in a.intersection(&b) {
-            assert!(expected.contains(x));
-            i += 1
-        }
-        assert_eq!(i, expected.len());
-    }
-
-    #[test]
-    fn test_difference() {
-        let mut a = HashSet::new();
-        let mut b = HashSet::new();
-
-        assert!(a.insert(1));
-        assert!(a.insert(3));
-        assert!(a.insert(5));
-        assert!(a.insert(9));
-        assert!(a.insert(11));
-
-        assert!(b.insert(3));
-        assert!(b.insert(9));
-
-        let mut i = 0;
-        let expected = [1, 5, 11];
-        for x in a.difference(&b) {
-            assert!(expected.contains(x));
-            i += 1
-        }
-        assert_eq!(i, expected.len());
-    }
-
-    #[test]
-    fn test_symmetric_difference() {
-        let mut a = HashSet::new();
-        let mut b = HashSet::new();
-
-        assert!(a.insert(1));
-        assert!(a.insert(3));
-        assert!(a.insert(5));
-        assert!(a.insert(9));
-        assert!(a.insert(11));
-
-        assert!(b.insert(-2));
-        assert!(b.insert(3));
-        assert!(b.insert(9));
-        assert!(b.insert(14));
-        assert!(b.insert(22));
-
-        let mut i = 0;
-        let expected = [-2, 1, 5, 11, 14, 22];
-        for x in a.symmetric_difference(&b) {
-            assert!(expected.contains(x));
-            i += 1
-        }
-        assert_eq!(i, expected.len());
-    }
-
-    #[test]
-    fn test_union() {
-        let mut a = HashSet::new();
-        let mut b = HashSet::new();
-
-        assert!(a.insert(1));
-        assert!(a.insert(3));
-        assert!(a.insert(5));
-        assert!(a.insert(9));
-        assert!(a.insert(11));
-        assert!(a.insert(16));
-        assert!(a.insert(19));
-        assert!(a.insert(24));
-
-        assert!(b.insert(-2));
-        assert!(b.insert(1));
-        assert!(b.insert(5));
-        assert!(b.insert(9));
-        assert!(b.insert(13));
-        assert!(b.insert(19));
-
-        let mut i = 0;
-        let expected = [-2, 1, 3, 5, 9, 11, 13, 16, 19, 24];
-        for x in a.union(&b) {
-            assert!(expected.contains(x));
-            i += 1
-        }
-        assert_eq!(i, expected.len());
-    }
-
-    #[test]
-    fn test_from_iter() {
-        let xs = [1, 2, 3, 4, 5, 6, 7, 8, 9];
-
-        let set: HashSet<_> = xs.iter().cloned().collect();
-
-        for x in &xs {
-            assert!(set.contains(x));
-        }
-    }
-
-    #[test]
-    fn test_move_iter() {
-        let hs = {
-            let mut hs = HashSet::new();
-
-            hs.insert('a');
-            hs.insert('b');
-
-            hs
-        };
-
-        let v = hs.into_iter().collect::<Vec<char>>();
-        assert!(['a', 'b'] == v || ['b', 'a'] == v);
-    }
-
-    #[test]
-    fn test_eq() {
-        // These constants once happened to expose a bug in insert().
-        // I'm keeping them around to prevent a regression.
-        let mut s1 = HashSet::new();
-
-        s1.insert(1);
-        s1.insert(2);
-        s1.insert(3);
-
-        let mut s2 = HashSet::new();
-
-        s2.insert(1);
-        s2.insert(2);
-
-        assert!(s1 != s2);
-
-        s2.insert(3);
-
-        assert_eq!(s1, s2);
-    }
-
-    #[test]
-    fn test_show() {
-        let mut set = HashSet::new();
-        let empty = HashSet::<i32>::new();
-
-        set.insert(1);
-        set.insert(2);
-
-        let set_str = format!("{:?}", set);
-
-        assert!(set_str == "HashSet {1, 2}" || set_str == "HashSet {2, 1}");
-        assert_eq!(format!("{:?}", empty), "HashSet {}");
-    }
-
-    #[test]
-    fn test_trivial_drain() {
-        let mut s = HashSet::<i32>::new();
-        for _ in s.drain() {}
-        assert!(s.is_empty());
-        drop(s);
-
-        let mut s = HashSet::<i32>::new();
-        drop(s.drain());
-        assert!(s.is_empty());
-    }
-
-    #[test]
-    fn test_drain() {
-        let mut s: HashSet<_> = (1..100).collect();
-
-        // try this a bunch of times to make sure we don't screw up internal state.
-        for _ in 0..20 {
-            assert_eq!(s.len(), 99);
-
-            {
-                let mut last_i = 0;
-                let mut d = s.drain();
-                for (i, x) in d.by_ref().take(50).enumerate() {
-                    last_i = i;
-                    assert!(x != 0);
-                }
-                assert_eq!(last_i, 49);
-            }
-
-            for _ in &s { panic!("s should be empty!"); }
-
-            // reset to try again.
-            s.extend(1..100);
-        }
-    }
-}
diff --git a/src/libstd/collections/hash/table.rs b/src/libstd/collections/hash/table.rs
index f301f6db92f..7513cb8a61c 100644
--- a/src/libstd/collections/hash/table.rs
+++ b/src/libstd/collections/hash/table.rs
@@ -143,25 +143,6 @@ impl SafeHash {
 /// We need to remove hashes of 0. That's reserved for empty buckets.
 /// This function wraps up `hash_keyed` to be the only way outside this
 /// module to generate a SafeHash.
-#[cfg(stage0)]
-pub fn make_hash<T: ?Sized, S, H>(hash_state: &S, t: &T) -> SafeHash
-    where T: Hash<H>,
-          S: HashState<Hasher=H>,
-          H: Hasher<Output=u64>
-{
-    let mut state = hash_state.hasher();
-    t.hash(&mut state);
-    // We need to avoid 0u64 in order to prevent collisions with
-    // EMPTY_HASH. We can maintain our precious uniform distribution
-    // of initial indexes by unconditionally setting the MSB,
-    // effectively reducing 64-bits hashes to 63 bits.
-    SafeHash { hash: 0x8000_0000_0000_0000 | state.finish() }
-}
-
-/// We need to remove hashes of 0. That's reserved for empty buckets.
-/// This function wraps up `hash_keyed` to be the only way outside this
-/// module to generate a SafeHash.
-#[cfg(not(stage0))]
 pub fn make_hash<T: ?Sized, S>(hash_state: &S, t: &T) -> SafeHash
     where T: Hash, S: HashState
 {