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-rw-r--r--rust/alloc/raw_vec.rs30
1 files changed, 20 insertions, 10 deletions
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
index 65d5ce15828e..a7425582a323 100644
--- a/rust/alloc/raw_vec.rs
+++ b/rust/alloc/raw_vec.rs
@@ -471,16 +471,26 @@ impl<T, A: Allocator> RawVec<T, A> {
let (ptr, layout) = if let Some(mem) = self.current_memory() { mem } else { return Ok(()) };
// See current_memory() why this assert is here
let _: () = const { assert!(mem::size_of::<T>() % mem::align_of::<T>() == 0) };
- let ptr = unsafe {
- // `Layout::array` cannot overflow here because it would have
- // overflowed earlier when capacity was larger.
- let new_size = mem::size_of::<T>().unchecked_mul(cap);
- let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
- self.alloc
- .shrink(ptr, layout, new_layout)
- .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
- };
- self.set_ptr_and_cap(ptr, cap);
+
+ // If shrinking to 0, deallocate the buffer. We don't reach this point
+ // for the T::IS_ZST case since current_memory() will have returned
+ // None.
+ if cap == 0 {
+ unsafe { self.alloc.deallocate(ptr, layout) };
+ self.ptr = Unique::dangling();
+ self.cap = 0;
+ } else {
+ let ptr = unsafe {
+ // `Layout::array` cannot overflow here because it would have
+ // overflowed earlier when capacity was larger.
+ let new_size = mem::size_of::<T>().unchecked_mul(cap);
+ let new_layout = Layout::from_size_align_unchecked(new_size, layout.align());
+ self.alloc
+ .shrink(ptr, layout, new_layout)
+ .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
+ };
+ self.set_ptr_and_cap(ptr, cap);
+ }
Ok(())
}
}