auto merge of #17268 : aturon/rust/mut-conventions, r=alexcrichton

As per [RFC 52](https://github.com/rust-lang/rfcs/blob/master/active/0052-ownership-variants.md), use `_mut` suffixes to mark mutable variants, and `into_iter` for moving iterators. Additional details and motivation in the RFC.

Note that the iterator *type* names are not changed by this RFC; those are awaiting a separate RFC for standardization.

Closes #13660
Closes #16810

[breaking-change]

src/compiletest/compiletest.rs

@@ -259,7 +259,7 @@ pub fn run_tests(config: &Config) {
     // parallel (especially when we have lots and lots of child processes).
     // For context, see #8904
     io::test::raise_fd_limit();
-    let res = test::run_tests_console(&opts, tests.move_iter().collect());
+    let res = test::run_tests_console(&opts, tests.into_iter().collect());
     match res {
         Ok(true) => {}
         Ok(false) => fail!("Some tests failed"),
@@ -400,4 +400,4 @@ fn extract_gdb_version(full_version_line: Option<String>) -> Option<String> {
         },
         _ => None
     }
-}
+}

src/compiletest/procsrv.rs

@@ -40,7 +40,7 @@ pub fn run(lib_path: &str,
     let mut cmd = Command::new(prog);
     cmd.args(args);
     add_target_env(&mut cmd, lib_path, aux_path);
-    for (key, val) in env.move_iter() {
+    for (key, val) in env.into_iter() {
         cmd.env(key, val);
     }
 
@@ -72,7 +72,7 @@ pub fn run_background(lib_path: &str,
     let mut cmd = Command::new(prog);
     cmd.args(args);
     add_target_env(&mut cmd, lib_path, aux_path);
-    for (key, val) in env.move_iter() {
+    for (key, val) in env.into_iter() {
         cmd.env(key, val);
     }
 

src/compiletest/runtest.rs

@@ -768,7 +768,7 @@ fn cleanup_debug_info_options(options: &Option<String>) -> Option<String> {
         "--debuginfo".to_string()
     ];
     let new_options =
-        split_maybe_args(options).move_iter()
+        split_maybe_args(options).into_iter()
                                  .filter(|x| !options_to_remove.contains(x))
                                  .collect::<Vec<String>>()
                                  .connect(" ");
@@ -1461,7 +1461,7 @@ fn _arm_exec_compiled_test(config: &Config,
 
     // run test via adb_run_wrapper
     runargs.push("shell".to_string());
-    for (key, val) in env.move_iter() {
+    for (key, val) in env.into_iter() {
         runargs.push(format!("{}={}", key, val));
     }
     runargs.push(format!("{}/adb_run_wrapper.sh", config.adb_test_dir));

src/doc/guide-tasks.md

@@ -238,7 +238,7 @@ fn main() {
     let mut futures = Vec::from_fn(1000, |ind| Future::spawn( proc() { partial_sum(ind) }));
 
     let mut final_res = 0f64;
-    for ft in futures.mut_iter()  {
+    for ft in futures.iter_mut()  {
         final_res += ft.get();
     }
     println!("π^2/6 is not far from : {}", final_res);

src/doc/guide.md

@@ -1319,7 +1319,7 @@ upper bound is exclusive, though, so our loop will print `0` through `9`, not
 
 Rust does not have the "C style" `for` loop on purpose. Manually controlling
 each element of the loop is complicated and error prone, even for experienced C
-developers. 
+developers.
 
 We'll talk more about `for` when we cover **iterator**s, later in the Guide.
 

src/liballoc/heap.rs

@@ -140,7 +140,7 @@ static MIN_ALIGN: uint = 16;
 #[cfg(jemalloc)]
 mod imp {
     use core::option::{None, Option};
-    use core::ptr::{RawPtr, mut_null, null};
+    use core::ptr::{RawPtr, null_mut, null};
     use core::num::Int;
     use libc::{c_char, c_int, c_void, size_t};
     use super::MIN_ALIGN;
@@ -230,7 +230,7 @@ mod imp {
 
     pub fn stats_print() {
         unsafe {
-            je_malloc_stats_print(None, mut_null(), null())
+            je_malloc_stats_print(None, null_mut(), null())
         }
     }
 }

src/liballoc/libc_heap.rs

@@ -12,15 +12,15 @@
 //! The global (exchange) heap.
 
 use libc::{c_void, size_t, free, malloc, realloc};
-use core::ptr::{RawPtr, mut_null};
+use core::ptr::{RawPtr, null_mut};
 
 /// A wrapper around libc::malloc, aborting on out-of-memory.
 #[inline]
 pub unsafe fn malloc_raw(size: uint) -> *mut u8 {
     // `malloc(0)` may allocate, but it may also return a null pointer
     // http://pubs.opengroup.org/onlinepubs/9699919799/functions/malloc.html
     if size == 0 {
-        mut_null()
+        null_mut()
     } else {
         let p = malloc(size as size_t);
         if p.is_null() {
@@ -37,7 +37,7 @@ pub unsafe fn realloc_raw(ptr: *mut u8, size: uint) -> *mut u8 {
     // http://pubs.opengroup.org/onlinepubs/9699919799/functions/realloc.html
     if size == 0 {
         free(ptr as *mut c_void);
-        mut_null()
+        null_mut()
     } else {
         let p = realloc(ptr as *mut c_void, size as size_t);
         if p.is_null() {

src/libarena/lib.rs

@@ -448,7 +448,7 @@ impl<T> TypedArena<T> {
     #[inline]
     pub fn with_capacity(capacity: uint) -> TypedArena<T> {
         unsafe {
-            let chunk = TypedArenaChunk::<T>::new(ptr::mut_null(), capacity);
+            let chunk = TypedArenaChunk::<T>::new(ptr::null_mut(), capacity);
             TypedArena {
                 ptr: Cell::new((*chunk).start() as *const T),
                 end: Cell::new((*chunk).end() as *const T),

src/libcollections/bitv.rs

@@ -178,7 +178,7 @@ impl Bitv {
         // `op` is a bitwise operation, since any bits that should've
         // been masked were fine to change anyway. `b` is masked to
         // make sure its unmasked bits do not cause damage.
-        for (a, (_, b)) in self.storage.mut_iter()
+        for (a, (_, b)) in self.storage.iter_mut()
                            .zip(other.mask_words(0)) {
             let w = op(*a, b);
             if *a != w {
@@ -310,7 +310,7 @@ impl Bitv {
     /// ```
     #[inline]
     pub fn set_all(&mut self) {
-        for w in self.storage.mut_iter() { *w = !0u; }
+        for w in self.storage.iter_mut() { *w = !0u; }
     }
 
     /// Flips all bits.
@@ -329,7 +329,7 @@ impl Bitv {
     /// ```
     #[inline]
     pub fn negate(&mut self) {
-        for w in self.storage.mut_iter() { *w = !*w; }
+        for w in self.storage.iter_mut() { *w = !*w; }
     }
 
     /// Calculates the union of two bitvectors. This acts like the bitwise `or`
@@ -797,7 +797,7 @@ impl Collection for Bitv {
 impl Mutable for Bitv {
     #[inline]
     fn clear(&mut self) {
-        for w in self.storage.mut_iter() { *w = 0u; }
+        for w in self.storage.iter_mut() { *w = 0u; }
     }
 }
 
@@ -831,7 +831,7 @@ impl Clone for Bitv {
     fn clone_from(&mut self, source: &Bitv) {
         self.nbits = source.nbits;
         self.storage.reserve(source.storage.len());
-        for (i, w) in self.storage.mut_iter().enumerate() { *w = source.storage[i]; }
+        for (i, w) in self.storage.iter_mut().enumerate() { *w = source.storage[i]; }
     }
 }
 

src/libcollections/dlist.rs

@@ -79,7 +79,7 @@ pub struct MoveItems<T> {
 impl<T> Rawlink<T> {
     /// Like Option::None for Rawlink
     fn none() -> Rawlink<T> {
-        Rawlink{p: ptr::mut_null()}
+        Rawlink{p: ptr::null_mut()}
     }
 
     /// Like Option::Some for Rawlink
@@ -431,7 +431,7 @@ impl<T> DList<T> {
     /// ```
     pub fn insert_when(&mut self, elt: T, f: |&T, &T| -> bool) {
         {
-            let mut it = self.mut_iter();
+            let mut it = self.iter_mut();
             loop {
                 match it.peek_next() {
                     None => break,
@@ -451,7 +451,7 @@ impl<T> DList<T> {
     /// This operation should compute in O(max(N, M)) time.
     pub fn merge(&mut self, mut other: DList<T>, f: |&T, &T| -> bool) {
         {
-            let mut it = self.mut_iter();
+            let mut it = self.iter_mut();
             loop {
                 let take_a = match (it.peek_next(), other.front()) {
                     (_   , None) => return,
@@ -475,9 +475,15 @@ impl<T> DList<T> {
         Items{nelem: self.len(), head: &self.list_head, tail: self.list_tail}
     }
 
+    /// Deprecated: use `iter_mut`.
+    #[deprecated = "use iter_mut"]
+    pub fn mut_iter<'a>(&'a mut self) -> MutItems<'a, T> {
+        self.iter_mut()
+    }
+
     /// Provides a forward iterator with mutable references.
     #[inline]
-    pub fn mut_iter<'a>(&'a mut self) -> MutItems<'a, T> {
+    pub fn iter_mut<'a>(&'a mut self) -> MutItems<'a, T> {
         let head_raw = match self.list_head {
             Some(ref mut h) => Rawlink::some(&mut **h),
             None => Rawlink::none(),
@@ -490,10 +496,15 @@ impl<T> DList<T> {
         }
     }
 
+    /// Deprecated: use `into_iter`.
+    #[deprecated = "use into_iter"]
+    pub fn move_iter(self) -> MoveItems<T> {
+        self.into_iter()
+    }
 
     /// Consumes the list into an iterator yielding elements by value.
     #[inline]
-    pub fn move_iter(self) -> MoveItems<T> {
+    pub fn into_iter(self) -> MoveItems<T> {
         MoveItems{list: self}
     }
 }
@@ -860,7 +871,7 @@ mod tests {
         check_links(&m);
         let sum = v.append(u.as_slice());
         assert_eq!(sum.len(), m.len());
-        for elt in sum.move_iter() {
+        for elt in sum.into_iter() {
             assert_eq!(m.pop_front(), Some(elt))
         }
     }
@@ -884,7 +895,7 @@ mod tests {
         check_links(&m);
         let sum = u.append(v.as_slice());
         assert_eq!(sum.len(), m.len());
-        for elt in sum.move_iter() {
+        for elt in sum.into_iter() {
             assert_eq!(m.pop_front(), Some(elt))
         }
     }
@@ -909,7 +920,7 @@ mod tests {
         m.rotate_backward(); check_links(&m);
         m.push_front(9); check_links(&m);
         m.rotate_forward(); check_links(&m);
-        assert_eq!(vec![3i,9,5,1,2], m.move_iter().collect());
+        assert_eq!(vec![3i,9,5,1,2], m.into_iter().collect());
     }
 
     #[test]
@@ -980,16 +991,16 @@ mod tests {
     fn test_mut_iter() {
         let mut m = generate_test();
         let mut len = m.len();
-        for (i, elt) in m.mut_iter().enumerate() {
+        for (i, elt) in m.iter_mut().enumerate() {
             assert_eq!(i as int, *elt);
             len -= 1;
         }
         assert_eq!(len, 0);
         let mut n = DList::new();
-        assert!(n.mut_iter().next().is_none());
+        assert!(n.iter_mut().next().is_none());
         n.push_front(4i);
         n.push(5);
-        let mut it = n.mut_iter();
+        let mut it = n.iter_mut();
         assert_eq!(it.size_hint(), (2, Some(2)));
         assert!(it.next().is_some());
         assert!(it.next().is_some());
@@ -1000,11 +1011,11 @@ mod tests {
     #[test]
     fn test_iterator_mut_double_end() {
         let mut n = DList::new();
-        assert!(n.mut_iter().next_back().is_none());
+        assert!(n.iter_mut().next_back().is_none());
         n.push_front(4i);
         n.push_front(5);
         n.push_front(6);
-        let mut it = n.mut_iter();
+        let mut it = n.iter_mut();
         assert_eq!(it.size_hint(), (3, Some(3)));
         assert_eq!(*it.next().unwrap(), 6);
         assert_eq!(it.size_hint(), (2, Some(2)));
@@ -1020,7 +1031,7 @@ mod tests {
         let mut m = list_from(&[0i,2,4,6,8]);
         let len = m.len();
         {
-            let mut it = m.mut_iter();
+            let mut it = m.iter_mut();
             it.insert_next(-2);
             loop {
                 match it.next() {
@@ -1039,7 +1050,7 @@ mod tests {
         }
         check_links(&m);
         assert_eq!(m.len(), 3 + len * 2);
-        assert_eq!(m.move_iter().collect::<Vec<int>>(), vec![-2,0,1,2,3,4,5,6,7,8,9,0,1]);
+        assert_eq!(m.into_iter().collect::<Vec<int>>(), vec![-2,0,1,2,3,4,5,6,7,8,9,0,1]);
     }
 
     #[test]
@@ -1050,7 +1061,7 @@ mod tests {
         m.merge(n, |a, b| a <= b);
         assert_eq!(m.len(), len);
         check_links(&m);
-        let res = m.move_iter().collect::<Vec<int>>();
+        let res = m.into_iter().collect::<Vec<int>>();
         assert_eq!(res, vec![-1, 0, 0, 0, 1, 3, 5, 6, 7, 2, 7, 7, 9]);
     }
 
@@ -1066,19 +1077,19 @@ mod tests {
         m.push(4);
         m.insert_ordered(3);
         check_links(&m);
-        assert_eq!(vec![2,3,4], m.move_iter().collect::<Vec<int>>());
+        assert_eq!(vec![2,3,4], m.into_iter().collect::<Vec<int>>());
     }
 
     #[test]
     fn test_mut_rev_iter() {
         let mut m = generate_test();
-        for (i, elt) in m.mut_iter().rev().enumerate() {
+        for (i, elt) in m.iter_mut().rev().enumerate() {
             assert_eq!((6-i) as int, *elt);
         }
         let mut n = DList::new();
-        assert!(n.mut_iter().rev().next().is_none());
+        assert!(n.iter_mut().rev().next().is_none());
         n.push_front(4i);
-        let mut it = n.mut_iter().rev();
+        let mut it = n.iter_mut().rev();
         assert!(it.next().is_some());
         assert!(it.next().is_none());
     }
@@ -1218,7 +1229,7 @@ mod tests {
         check_links(&m);
 
         let mut i = 0u;
-        for (a, &b) in m.move_iter().zip(v.iter()) {
+        for (a, &b) in m.into_iter().zip(v.iter()) {
             i += 1;
             assert_eq!(a, b);
         }
@@ -1300,7 +1311,7 @@ mod tests {
         let v = &[0i, ..128];
         let mut m: DList<int> = v.iter().map(|&x|x).collect();
         b.iter(|| {
-            assert!(m.mut_iter().count() == 128);
+            assert!(m.iter_mut().count() == 128);
         })
     }
     #[bench]
@@ -1316,7 +1327,7 @@ mod tests {
         let v = &[0i, ..128];
         let mut m: DList<int> = v.iter().map(|&x|x).collect();
         b.iter(|| {
-            assert!(m.mut_iter().rev().count() == 128);
+            assert!(m.iter_mut().rev().count() == 128);
         })
     }
 }