a basic owning reference implementation

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "ownref"
+version = "0.1.0"

Cargo.toml

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+[package]
+name = "ownref"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

rustfmt.toml

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+hard_tabs = true

src/lib.rs

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+use std::{
+	marker::PhantomData,
+	mem::ManuallyDrop,
+	ops::{Deref, DerefMut},
+	ptr::{self, NonNull},
+};
+
+pub struct OwnRef<'a, T: ?Sized>(Option<NonNull<T>>, PhantomData<&'a mut T>);
+
+impl<T: ?Sized> Drop for OwnRef<'_, T> {
+	fn drop(&mut self) {
+		let Some(p) = self.0 else { return };
+		unsafe { ptr::drop_in_place(p.as_ptr()) };
+	}
+}
+
+impl<T: ?Sized> Deref for OwnRef<'_, T> {
+	type Target = T;
+	fn deref(&self) -> &Self::Target {
+		unsafe { self.0.unwrap().as_ref() }
+	}
+}
+
+impl<T: ?Sized> DerefMut for OwnRef<'_, T> {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		unsafe { self.0.unwrap().as_mut() }
+	}
+}
+
+impl<T: ?Sized> OwnRef<'_, T> {
+	pub unsafe fn new_unchecked(p: *mut T) -> Self {
+		Self(Some(NonNull::new(p).unwrap()), PhantomData)
+	}
+}
+
+impl<'a, T: ?Sized> OwnRef<'a, T> {
+	pub unsafe fn from_manually_drop(p: &'a mut ManuallyDrop<T>) -> Self {
+		unsafe { Self::new_unchecked(p.deref_mut() as *mut _) }
+	}
+}
+
+impl<T: Sized> OwnRef<'_, T> {
+	pub fn take(mut self) -> T {
+		let p = self.0.take().unwrap();
+		unsafe { p.read() }
+	}
+}
+
+impl OwnRef<'_, dyn std::any::Any> {
+	pub fn take<U: 'static>(mut self) -> Option<U> {
+		if !self.is::<U>() {
+			return None;
+		}
+		let p = self.0.take().unwrap();
+		let p = p.cast::<U>();
+		Some(unsafe { p.read() })
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+}