auto merge of #13183 : erickt/rust/remove-list, r=alexcrichton

`collections::list::List` was decided in a [team meeting](https://github.com/mozilla/rust/wiki/Meeting-weekly-2014-03-25) that it was unnecessary, so this PR removes it. Additionally, it removes an old and redundant purity test and fixes some warnings.

src/test/bench/task-perf-alloc-unwind.rs

@@ -13,12 +13,16 @@
 extern crate collections;
 extern crate time;
 
-use collections::list::{List, Cons, Nil};
 use time::precise_time_s;
 use std::os;
 use std::task;
 use std::vec;
 
+#[deriving(Clone)]
+enum List<T> {
+    Nil, Cons(T, @List<T>)
+}
+
 enum UniqueList {
     ULNil, ULCons(~UniqueList)
 }

src/test/run-pass/log-knows-the-names-of-variants-in-std.rs

@@ -10,9 +10,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate collections;
-use collections::list::List;
-
 #[deriving(Clone)]
 enum foo {
   a(uint),
@@ -24,9 +21,21 @@ fn check_log<T>(exp: ~str, v: T) {
 }
 
 pub fn main() {
-    let x = List::from_vec([a(22u), b(~"hi")]);
-    let exp = ~"Cons(a(22u), @Cons(b(~\"hi\"), @Nil))";
+    let mut x = Some(a(22u));
+    let exp = ~"Some(a(22u))";
     let act = format!("{:?}", x);
-    assert!(act == exp);
+    assert_eq!(act, exp);
+    check_log(exp, x);
+
+    x = Some(b(~"hi"));
+    let exp = ~"Some(b(~\"hi\"))";
+    let act = format!("{:?}", x);
+    assert_eq!(act, exp);
+    check_log(exp, x);
+
+    x = None;
+    let exp = ~"None";
+    let act = format!("{:?}", x);
+    assert_eq!(act, exp);
     check_log(exp, x);
 }

src/test/run-pass/non-boolean-pure-fns.rs

@@ -1,36 +0,0 @@
-// ignore-fast
-
-// Copyright 2012-2014 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.
-
-#[feature(managed_boxes)];
-
-extern crate collections;
-
-use collections::list::{List, Cons, Nil};
-
-fn pure_length_go<T>(ls: @List<T>, acc: uint) -> uint {
-    match *ls { Nil => { acc } Cons(_, tl) => { pure_length_go(tl, acc + 1u) } }
-}
-
-fn pure_length<T>(ls: @List<T>) -> uint { pure_length_go(ls, 0u) }
-
-fn nonempty_list<T>(ls: @List<T>) -> bool { pure_length(ls) > 0u }
-
-fn safe_head<T:Clone>(ls: @List<T>) -> T {
-    assert!(!ls.is_empty());
-    return ls.head().unwrap().clone();
-}
-
-pub fn main() {
-    let mylist = @Cons(@1u, @Nil);
-    assert!((nonempty_list(mylist)));
-    assert_eq!(*safe_head(mylist), 1u);
-}