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Remove object lifetime cast #1

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Remove object lifetime cast #1

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9 changes: 7 additions & 2 deletions src/context.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,12 @@ impl AllocationContext {
#[allow(dyn_drop)]
pub fn as_ptr<T>(&mut self, value: T) -> *const T {
let ptr = Box::into_raw(Box::new(value));
self.allocations.push(ptr as *const dyn Droppable);
// Safety: We extend the lifetime of the object type from some anonymous lifetime that `T`
// outlives, to `'static`. I don't know if this is sound or not.
let transmuted_ptr = unsafe {
std::mem::transmute::<*mut (dyn Droppable + '_), *const (dyn Droppable + 'static)>(ptr)
};
self.allocations.push(transmuted_ptr)
ptr
}

Expand Down Expand Up @@ -111,4 +116,4 @@ impl<'a, 'b> Drop for OwnedEvaluationContext<'a, 'b> {
self.sexps.drain(..).for_each(|ptr| unsafe { drop(Box::from_raw(ptr as *mut Sexp<'a>)); });
unsafe { self.allocations.drop() }
}
}
}