impl TrustedRandomAccess for vec::IntoIter

Author: the8472

src/liballoc/vec.rs

@@ -61,7 +61,9 @@ use core::cmp::{self, Ordering};
 use core::fmt;
 use core::hash::{self, Hash};
 use core::intrinsics::{arith_offset, assume};
-use core::iter::{FromIterator, FusedIterator, InPlaceIterable, SourceIter, TrustedLen};
+use core::iter::{
+    FromIterator, FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccess,
+};
 use core::marker::PhantomData;
 use core::mem;
 use core::ops::Bound::{Excluded, Included, Unbounded};
@@ -2795,6 +2797,22 @@ impl<T> FusedIterator for IntoIter<T> {}
 #[unstable(feature = "trusted_len", issue = "37572")]
 unsafe impl<T> TrustedLen for IntoIter<T> {}
 
+#[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
+// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
+// and thus we can't implement drop-handling
+unsafe impl<T> TrustedRandomAccess for IntoIter<T>
+where
+    T: Copy,
+{
+    unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
+        if mem::size_of::<T>() == 0 { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
+    }
+    fn may_have_side_effect() -> bool {
+        false
+    }
+}
+
 #[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
 impl<T: Clone> Clone for IntoIter<T> {
     fn clone(&self) -> IntoIter<T> {

src/libcore/iter/adapters/mod.rs

@@ -16,8 +16,9 @@ mod zip;
 pub use self::chain::Chain;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::flatten::{FlatMap, Flatten};
-pub(crate) use self::zip::TrustedRandomAccess;
 pub use self::zip::Zip;
+#[unstable(issue = "0", feature = "std_internals")]
+pub use self::zip::TrustedRandomAccess;
 
 /// This trait provides transitive access to source-stages in an interator-adapter pipeline
 /// under the conditions that
@@ -318,6 +319,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Copied<I>
 where
     I: TrustedRandomAccess<Item = &'a T>,
@@ -448,6 +450,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
 where
     I: TrustedRandomAccess<Item = &'a T>,
@@ -464,6 +467,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, I, T: 'a> TrustedRandomAccess for Cloned<I>
 where
     I: TrustedRandomAccess<Item = &'a T>,
@@ -931,6 +935,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<B, I, F> TrustedRandomAccess for Map<I, F>
 where
     I: TrustedRandomAccess,
@@ -1446,6 +1451,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<I> TrustedRandomAccess for Enumerate<I>
 where
     I: TrustedRandomAccess,
@@ -2638,6 +2644,7 @@ where
     }
 }
 
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<I> TrustedRandomAccess for Fuse<I>
 where
     I: TrustedRandomAccess,

src/libcore/iter/adapters/zip.rs

@@ -262,6 +262,7 @@ where
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<A, B> TrustedRandomAccess for Zip<A, B>
 where
     A: TrustedRandomAccess,
@@ -322,7 +323,10 @@ unsafe impl<A: InPlaceIterable, B: Iterator> InPlaceIterable for Zip<A, B> {}
 /// .get_unchecked() must return distinct mutable references for distinct
 /// indices (if applicable), and must return a valid reference if index is in
 /// 0..self.len().
-pub(crate) unsafe trait TrustedRandomAccess: ExactSizeIterator {
+#[unstable(issue = "0", feature = "std_internals")]
+pub unsafe trait TrustedRandomAccess: ExactSizeIterator {
+    /// Returns item at offset `i` from the current position of the iterator.
+    /// It does not advance the iterator.
     unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item;
     /// Returns `true` if getting an iterator element may have
     /// side effects. Remember to take inner iterators into account.

src/libcore/iter/mod.rs

@@ -360,14 +360,16 @@ pub use self::adapters::MapWhile;
 pub use self::adapters::SourceIter;
 #[stable(feature = "iterator_step_by", since = "1.28.0")]
 pub use self::adapters::StepBy;
+#[unstable(issue = "0", feature = "std_internals")]
+pub use self::adapters::TrustedRandomAccess;
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::adapters::{Chain, Cycle, Enumerate, Filter, FilterMap, Map, Rev, Zip};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::adapters::{FlatMap, Peekable, Scan, Skip, SkipWhile, Take, TakeWhile};
 #[stable(feature = "rust1", since = "1.0.0")]
 pub use self::adapters::{Fuse, Inspect};
 
-pub(crate) use self::adapters::{process_results, TrustedRandomAccess};
+pub(crate) use self::adapters::process_results;
 
 mod adapters;
 mod range;

src/libcore/slice/mod.rs

@@ -4210,6 +4210,7 @@ unsafe impl<T> TrustedLen for Windows<'_, T> {}
 impl<T> FusedIterator for Windows<'_, T> {}
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for Windows<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
         from_raw_parts(self.v.as_ptr().add(i), self.size)
@@ -4349,6 +4350,7 @@ unsafe impl<T> TrustedLen for Chunks<'_, T> {}
 impl<T> FusedIterator for Chunks<'_, T> {}
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for Chunks<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
         let start = i * self.chunk_size;
@@ -4491,6 +4493,7 @@ unsafe impl<T> TrustedLen for ChunksMut<'_, T> {}
 impl<T> FusedIterator for ChunksMut<'_, T> {}
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for ChunksMut<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut [T] {
         let start = i * self.chunk_size;
@@ -4631,7 +4634,7 @@ unsafe impl<T> TrustedLen for ChunksExact<'_, T> {}
 impl<T> FusedIterator for ChunksExact<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "chunks_exact", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for ChunksExact<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
         let start = i * self.chunk_size;
@@ -4765,7 +4768,7 @@ unsafe impl<T> TrustedLen for ChunksExactMut<'_, T> {}
 impl<T> FusedIterator for ChunksExactMut<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "chunks_exact", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for ChunksExactMut<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut [T] {
         let start = i * self.chunk_size;
@@ -4908,7 +4911,7 @@ unsafe impl<T> TrustedLen for RChunks<'_, T> {}
 impl<T> FusedIterator for RChunks<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "rchunks", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for RChunks<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
         let end = self.v.len() - i * self.chunk_size;
@@ -5053,7 +5056,7 @@ unsafe impl<T> TrustedLen for RChunksMut<'_, T> {}
 impl<T> FusedIterator for RChunksMut<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "rchunks", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for RChunksMut<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut [T] {
         let end = self.v.len() - i * self.chunk_size;
@@ -5197,7 +5200,7 @@ unsafe impl<T> TrustedLen for RChunksExact<'_, T> {}
 impl<T> FusedIterator for RChunksExact<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "rchunks", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for RChunksExact<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a [T] {
         let end = self.v.len() - i * self.chunk_size;
@@ -5336,7 +5339,7 @@ unsafe impl<T> TrustedLen for RChunksExactMut<'_, T> {}
 impl<T> FusedIterator for RChunksExactMut<'_, T> {}
 
 #[doc(hidden)]
-#[stable(feature = "rchunks", since = "1.31.0")]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for RChunksExactMut<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut [T] {
         let end = self.v.len() - i * self.chunk_size;
@@ -5683,6 +5686,7 @@ impl_marker_for!(BytewiseEquality,
                  u8 i8 u16 i16 u32 i32 u64 i64 u128 i128 usize isize char bool);
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for Iter<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a T {
         &*self.ptr.as_ptr().add(i)
@@ -5693,6 +5697,7 @@ unsafe impl<'a, T> TrustedRandomAccess for Iter<'a, T> {
 }
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl<'a, T> TrustedRandomAccess for IterMut<'a, T> {
     unsafe fn get_unchecked(&mut self, i: usize) -> &'a mut T {
         &mut *self.ptr.as_ptr().add(i)

src/libcore/str/mod.rs

@@ -863,6 +863,7 @@ impl FusedIterator for Bytes<'_> {}
 unsafe impl TrustedLen for Bytes<'_> {}
 
 #[doc(hidden)]
+#[unstable(issue = "0", feature = "std_internals")]
 unsafe impl TrustedRandomAccess for Bytes<'_> {
     unsafe fn get_unchecked(&mut self, i: usize) -> u8 {
         self.0.get_unchecked(i)