impl Needle<&[T]> for &&[T], &Box<[T]>.

src/liballoc/boxed.rs

@@ -78,6 +78,7 @@ use core::hash::{Hash, Hasher};
 use core::iter::{Iterator, FromIterator, FusedIterator};
 use core::marker::{Unpin, Unsize};
 use core::mem;
+use core::needle::Needle;
 use core::pin::Pin;
 use core::ops::{
     CoerceUnsized, DispatchFromDyn, Deref, DerefMut, Receiver, Generator, GeneratorState
@@ -919,3 +920,35 @@ impl<F: ?Sized + Future + Unpin> Future for Box<F> {
         F::poll(Pin::new(&mut *self), cx)
     }
 }
+
+#[unstable(feature = "needle", issue = "56345")]
+impl<'p, 'h, T: PartialEq + 'p + 'h> Needle<&'h [T]> for &'p Box<[T]> {
+    type Searcher = <&'p [T] as Needle<&'h [T]>>::Searcher;
+    type Consumer = <&'p [T] as Needle<&'h [T]>>::Consumer;
+
+    #[inline]
+    fn into_searcher(self) -> Self::Searcher {
+        <&'p [T] as Needle<&'h [T]>>::into_searcher(&**self)
+    }
+
+    #[inline]
+    fn into_consumer(self) -> Self::Consumer {
+        <&'p [T] as Needle<&'h [T]>>::into_consumer(&**self)
+    }
+}
+
+#[unstable(feature = "needle", issue = "56345")]
+impl<'p, 'h, T: PartialEq + 'p + 'h> Needle<&'h mut [T]> for &'p Box<[T]> {
+    type Searcher = <&'p [T] as Needle<&'h mut [T]>>::Searcher;
+    type Consumer = <&'p [T] as Needle<&'h mut [T]>>::Consumer;
+
+    #[inline]
+    fn into_searcher(self) -> Self::Searcher {
+        <&'p [T] as Needle<&'h mut [T]>>::into_searcher(&**self)
+    }
+
+    #[inline]
+    fn into_consumer(self) -> Self::Consumer {
+        <&'p [T] as Needle<&'h mut [T]>>::into_consumer(&**self)
+    }
+}

src/liballoc/tests/slice.rs

@@ -1709,3 +1709,10 @@ fn test_replace() {
         b" **E**mpowering **E**veryone to build reliable and **E**fficient software.".to_vec()
     );
 }
+
+#[test]
+fn test_boxed_slice_ref_is_a_needle() {
+    let boundary = vec![b'x'; 12].into_boxed_slice();
+    let bytes: &[u8] = b"--xxxxxxxxxxxxyyyy";
+    assert!(bytes[2..].starts_with(&boundary));
+}

src/libcore/slice/needles.rs

@@ -699,8 +699,8 @@ where
 }
 
 macro_rules! impl_needle_for_slice_searcher {
-    (@<$haystack:ty> for $ty:ty) => {
-        impl<'p, 'h, T> Needle<$haystack> for $ty
+    ([$($gen:tt)+] <$haystack:ty> for $ty:ty) => {
+        impl<$($gen)+, 'h, T> Needle<$haystack> for $ty
         where
             T: PartialEq + 'p,
         {
@@ -720,11 +720,13 @@ macro_rules! impl_needle_for_slice_searcher {
     };
 
     ($($index:expr),*) => {
-        impl_needle_for_slice_searcher!(@<&'h [T]> for &'p [T]);
-        impl_needle_for_slice_searcher!(@<&'h mut [T]> for &'p [T]);
+        impl_needle_for_slice_searcher!(['p] <&'h [T]> for &'p [T]);
+        impl_needle_for_slice_searcher!(['p] <&'h mut [T]> for &'p [T]);
+        impl_needle_for_slice_searcher!(['q, 'p] <&'h [T]> for &'q &'p [T]);
+        impl_needle_for_slice_searcher!(['q, 'p] <&'h mut [T]> for &'q &'p [T]);
         $(
-            impl_needle_for_slice_searcher!(@<&'h [T]> for &'p [T; $index]);
-            impl_needle_for_slice_searcher!(@<&'h mut [T]> for &'p [T; $index]);
+            impl_needle_for_slice_searcher!(['p] <&'h [T]> for &'p [T; $index]);
+            impl_needle_for_slice_searcher!(['p] <&'h mut [T]> for &'p [T; $index]);
         )*
     }
 }

src/libcore/tests/slice.rs

@@ -1475,3 +1475,10 @@ fn test_is_sorted() {
     assert!(!["c", "bb", "aaa"].is_sorted());
     assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
 }
+
+#[test]
+fn test_double_array_ref_is_a_needle() {
+    static MAGIC_NUMBERS: [&[u8]; 2] = [b"%PDF", b"\x89PNG"];
+    let buffer: &[u8] = b"%PDF123";
+    assert!(MAGIC_NUMBERS.iter().any(|magic| buffer.starts_with(magic)));
+}

src/test/ui/issues/issue-2149.stderr

@@ -10,7 +10,7 @@ error[E0599]: no method named `bind` found for type `[&str; 1]` in the current s
   --> $DIR/issue-2149.rs:13:12
    |
 LL |     ["hi"].bind(|x| [x] );
-   |            ^^^^ help: did you mean: `find`
+   |            ^^^^ help: there is a method with a similar name: `find`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `bind`, perhaps you need to implement it: