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Vec drop and truncate: drop using raw slice *mut [T] #71148

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May 1, 2020
Merged

Vec drop and truncate: drop using raw slice *mut [T] #71148

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Vec drop and truncate: drop using raw slice *mut [T]
bluss Apr 14, 2020
f654daf
Vec IntoIter: Drop using raw slice
bluss Apr 28, 2020
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4 changes: 2 additions & 2 deletions src/liballoc/vec.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -741,7 +741,7 @@ impl<T> Vec<T> {
return;
}
let remaining_len = self.len - len;
let s = slice::from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len);
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let s = ptr::slice_from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len);
self.len = len;
ptr::drop_in_place(s);
}
Expand Down Expand Up @@ -2379,7 +2379,7 @@ unsafe impl<#[may_dangle] T> Drop for Vec<T> {
fn drop(&mut self) {
unsafe {
// use drop for [T]
ptr::drop_in_place(&mut self[..]);
ptr::drop_in_place(ptr::slice_from_raw_parts_mut(self.as_mut_ptr(), self.len))
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Might be worth adding a brief comment for why we use this complicated operation here instead of the simple one.

Really, already for #70558, what we should really have is a way to get a raw slice for the entire Vec, and then subslicing on raw slices. Then we would not have to call slice_from_raw_parts for any of the methods changed in that PR or here.

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Comment added, though it's very vague since I don't dare say so much about what it actually allows

}
// RawVec handles deallocation
}
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