Method downcast_exact

crates/vm/src/object/core.rs:1301–1313

(self, vm: &VirtualMachine)

    /// another downcast can be attempted without unnecessary cloning.
    #[inline]
    pub fn downcast_exact<T: PyPayload>(self, vm: &VirtualMachine) -> Result<PyRefExact<T>, Self> {
        if self.class().is(T::class(&vm.ctx)) {
            // TODO: is this always true?
            assert!(
                self.downcastable::<T>(),
                "obj.__class__ is T::class() but payload is not T"
            );
            // SAFETY: just asserted that downcastable::<T>()
            Ok(unsafe { PyRefExact::new_unchecked(PyRef::from_obj_unchecked(self)) })
        } else {
            Err(self)
        }
    }
}

impl PyObject {