#[lang = "drop_in_place"]pub unsafe fn drop_in_place<T>(to_drop: *mut T) where
Executes the destructor (if any) of the pointed-to value.
This has two use cases:
It is required to use
drop_in_placeto drop unsized types like trait objects, because they can't be read out onto the stack and dropped normally.
It is friendlier to the optimizer to do this over
ptr::readwhen dropping manually allocated memory (e.g. when writing Box/Rc/Vec), as the compiler doesn't need to prove that it's sound to elide the copy.
This has all the same safety problems as
ptr::read with respect to
invalid pointers, types, and double drops.