vec: More specialization for Extend<&T> for vec
Specialize to use copy_from_slice when extending a Vec with &[T] where T: Copy.
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@ -1244,7 +1244,7 @@ impl<T: Clone> Vec<T> {
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/// ```
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#[stable(feature = "vec_extend_from_slice", since = "1.6.0")]
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pub fn extend_from_slice(&mut self, other: &[T]) {
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self.extend(other.iter().cloned())
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self.spec_extend(other.iter())
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}
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}
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@ -1499,7 +1499,7 @@ impl<T> ops::DerefMut for Vec<T> {
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impl<T> FromIterator<T> for Vec<T> {
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#[inline]
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fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Vec<T> {
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<Self as SpecExtend<_>>::from_iter(iter.into_iter())
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<Self as SpecExtend<_, _>>::from_iter(iter.into_iter())
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}
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}
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@ -1572,12 +1572,12 @@ impl<T> Extend<T> for Vec<T> {
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}
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// Specialization trait used for Vec::from_iter and Vec::extend
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trait SpecExtend<I> {
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trait SpecExtend<T, I> {
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fn from_iter(iter: I) -> Self;
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fn spec_extend(&mut self, iter: I);
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}
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impl<I, T> SpecExtend<I> for Vec<T>
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impl<T, I> SpecExtend<T, I> for Vec<T>
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where I: Iterator<Item=T>,
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{
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default fn from_iter(mut iterator: I) -> Self {
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@ -1607,7 +1607,7 @@ impl<I, T> SpecExtend<I> for Vec<T>
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}
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}
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impl<I, T> SpecExtend<I> for Vec<T>
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impl<T, I> SpecExtend<T, I> for Vec<T>
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where I: TrustedLen<Item=T>,
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{
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fn from_iter(iterator: I) -> Self {
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@ -1642,6 +1642,33 @@ impl<I, T> SpecExtend<I> for Vec<T>
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}
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}
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impl<'a, T: 'a, I> SpecExtend<&'a T, I> for Vec<T>
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where I: Iterator<Item=&'a T>,
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T: Clone,
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{
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default fn from_iter(iterator: I) -> Self {
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SpecExtend::from_iter(iterator.cloned())
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}
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default fn spec_extend(&mut self, iterator: I) {
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self.spec_extend(iterator.cloned())
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}
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}
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impl<'a, T: 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T>
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where T: Copy,
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{
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fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
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let slice = iterator.as_slice();
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self.reserve(slice.len());
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unsafe {
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let len = self.len();
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self.set_len(len + slice.len());
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self.get_unchecked_mut(len..).copy_from_slice(slice);
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}
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}
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}
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impl<T> Vec<T> {
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fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) {
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// This is the case for a general iterator.
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@ -1669,7 +1696,7 @@ impl<T> Vec<T> {
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#[stable(feature = "extend_ref", since = "1.2.0")]
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impl<'a, T: 'a + Copy> Extend<&'a T> for Vec<T> {
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fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
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self.extend(iter.into_iter().map(|&x| x))
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self.spec_extend(iter.into_iter())
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}
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}
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