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]

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index c28b6c144a2..5557ef9943b 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -485,7 +485,7 @@ mod imp {
                     let bytes = path.as_vec();
                     if bytes.len() < LAST_FILENAME.len() {
                         let i = bytes.iter();
-                        for (slot, val) in LAST_FILENAME.mut_iter().zip(i) {
+                        for (slot, val) in LAST_FILENAME.iter_mut().zip(i) {
                             *slot = *val as libc::c_char;
                         }
                         LAST_FILENAME.as_ptr()
@@ -496,7 +496,7 @@ mod imp {
                 None => ptr::null(),
             };
             STATE = backtrace_create_state(filename, 0, error_cb,
-                                           ptr::mut_null());
+                                           ptr::null_mut());
             return STATE
         }