Demode some code using by-mutbl-ref; warn about by-mutbl-ref

The parser now warns about use of mutbl-ref mode, though it's kind
of a lie since this commit doesn't remove support for the mode.

Changed move_val_init to have stage0 and stage1/2 versions, the latter of
which is demoded.

Changed the type that the typechecker expects the move_val_init
intrinsic to have. After this is pushed, I can make a new snapshot,
which will remove the need for the stage0 versions.

src/libcore/at_vec.rs

@@ -21,7 +21,11 @@ extern mod rustrt {
 #[abi = "rust-intrinsic"]
 extern mod rusti {
     #[legacy_exports];
+    #[cfg(stage0)]
     fn move_val_init<T>(&dst: T, -src: T);
+    #[cfg(stage1)]
+    #[cfg(stage2)]
+    fn move_val_init<T>(dst: &mut T, -src: T);
 }
 
 /// Returns the number of elements the vector can hold without reallocating
@@ -176,7 +180,9 @@ pub mod raw {
             push_slow(v, move initval);
         }
     }
+
     // This doesn't bother to make sure we have space.
+    #[cfg(stage0)]
     #[inline(always)] // really pretty please
     pub unsafe fn push_fast<T>(v: &mut @[const T], initval: T) {
         let repr: **VecRepr = ::cast::reinterpret_cast(&v);
@@ -186,6 +192,18 @@ pub mod raw {
         let p = ptr::offset(p, fill) as *mut T;
         rusti::move_val_init(*p, move initval);
     }
+    // This doesn't bother to make sure we have space.
+    #[cfg(stage1)]
+    #[cfg(stage2)]
+    #[inline(always)] // really pretty please
+    pub unsafe fn push_fast<T>(v: &mut @[const T], initval: T) {
+        let repr: **VecRepr = ::cast::reinterpret_cast(&v);
+        let fill = (**repr).unboxed.fill;
+        (**repr).unboxed.fill += sys::size_of::<T>();
+        let p = addr_of(&((**repr).unboxed.data));
+        let p = ptr::offset(p, fill) as *mut T;
+        rusti::move_val_init(&mut(*p), move initval);
+    }
 
     pub unsafe fn push_slow<T>(v: &mut @[const T], initval: T) {
         reserve_at_least(v, v.len() + 1u);