rollup merge of #24487: erickt/syntax

This removes the usage of `#[feature(into_cow, slice_patterns, box_syntax, box_patterns, quote, unsafe_destructor)]` from being used in libsyntax. My main desire for this is that it brings me one step closer to letting [syntex](https://github.com/erickt/rust-syntex) compile with stable rust. Hopefully this doesn't inconvenience rust development.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/libsyntax/util/small_vector.rs b/src/libsyntax/util/small_vector.rs
index 6b864d52947..153f9d4a26d 100644
--- a/src/libsyntax/util/small_vector.rs
+++ b/src/libsyntax/util/small_vector.rs
@@ -64,7 +64,10 @@ impl<T> SmallVector<T> {
                 let result: &[T] = &[];
                 result
             }
-            One(ref v) => slice::ref_slice(v),
+            One(ref v) => {
+                // FIXME: Could be replaced with `slice::ref_slice(v)` when it is stable.
+                unsafe { slice::from_raw_parts(v, 1) }
+            }
             Many(ref vs) => vs
         }
     }