From 3acc3c4d85e017edde2149eaabd44a78be5f7e17 Mon Sep 17 00:00:00 2001
From: Eric Holk <eric.holk@gmail.com>
Date: Thu, 31 May 2012 10:26:05 -0700
Subject: [PATCH] Make std::map require const keys.

---
 src/libstd/map.rs              |  8 +++++---
 src/libsyntax/util/interner.rs | 10 +++++-----
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/libstd/map.rs b/src/libstd/map.rs
index 4967eaf9f850..08ae0bd80c41 100644
--- a/src/libstd/map.rs
+++ b/src/libstd/map.rs
@@ -282,7 +282,7 @@ Parameters:
 hasher - The hash function for key type K
 eqer - The equality function for key type K
 */
-fn hashmap<K: copy, V: copy>(hasher: hashfn<K>, eqer: eqfn<K>)
+fn hashmap<K: const copy, V: copy>(hasher: hashfn<K>, eqer: eqfn<K>)
         -> hashmap<K, V> {
     chained::mk(hasher, eqer)
 }
@@ -316,7 +316,9 @@ fn uint_hash<V: copy>() -> hashmap<uint, V> {
 #[doc = "
 Convenience function for adding keys to a hashmap with nil type keys
 "]
-fn set_add<K: copy>(set: set<K>, key: K) -> bool { ret set.insert(key, ()); }
+fn set_add<K: const copy>(set: set<K>, key: K) -> bool {
+    ret set.insert(key, ());
+}
 
 #[doc = "
 Convert a set into a vector.
@@ -331,7 +333,7 @@ fn vec_from_set<T: copy>(s: set<T>) -> [T] {
 }
 
 #[doc = "Construct a hashmap from a vector"]
-fn hash_from_vec<K: copy, V: copy>(hasher: hashfn<K>, eqer: eqfn<K>,
+fn hash_from_vec<K: const copy, V: copy>(hasher: hashfn<K>, eqer: eqfn<K>,
                                    items: [(K, V)]) -> hashmap<K, V> {
     let map = hashmap(hasher, eqer);
     vec::iter(items) { |item|
diff --git a/src/libsyntax/util/interner.rs b/src/libsyntax/util/interner.rs
index 89078bfaa363..0e69f2c10b7b 100644
--- a/src/libsyntax/util/interner.rs
+++ b/src/libsyntax/util/interner.rs
@@ -5,18 +5,18 @@ import std::map;
 import std::map::{hashmap, hashfn, eqfn};
 import dvec::{dvec, extensions};
 
-type interner<T> =
+type interner<T: const> =
     {map: hashmap<T, uint>,
      vect: dvec<T>,
      hasher: hashfn<T>,
      eqer: eqfn<T>};
 
-fn mk<T: copy>(hasher: hashfn<T>, eqer: eqfn<T>) -> interner<T> {
+fn mk<T: const copy>(hasher: hashfn<T>, eqer: eqfn<T>) -> interner<T> {
     let m = map::hashmap::<T, uint>(hasher, eqer);
     ret {map: m, vect: dvec(), hasher: hasher, eqer: eqer};
 }
 
-fn intern<T: copy>(itr: interner<T>, val: T) -> uint {
+fn intern<T: const copy>(itr: interner<T>, val: T) -> uint {
     alt itr.map.find(val) {
       some(idx) { ret idx; }
       none {
@@ -31,10 +31,10 @@ fn intern<T: copy>(itr: interner<T>, val: T) -> uint {
 // |get| isn't "pure" in the traditional sense, because it can go from
 // failing to returning a value as items are interned. But for typestate,
 // where we first check a pred and then rely on it, ceasing to fail is ok.
-pure fn get<T: copy>(itr: interner<T>, idx: uint) -> T {
+pure fn get<T: const copy>(itr: interner<T>, idx: uint) -> T {
     unchecked {
         itr.vect.get_elt(idx)
     }
 }
 
-fn len<T>(itr: interner<T>) -> uint { ret itr.vect.len(); }
+fn len<T: const>(itr: interner<T>) -> uint { ret itr.vect.len(); }