add test

tests/ui/drop/issue-110682.rs

@@ -0,0 +1,92 @@
+// build-pass
+// compile-flags: -Zmir-opt-level=3
+
+use std::fmt::Debug;
+use std::mem::ManuallyDrop;
+use std::ptr;
+
+pub trait BitRegister {}
+
+macro_rules! register {
+    ($($t:ty),+ $(,)?) => { $(
+        impl BitRegister for $t {
+        }
+    )* };
+}
+
+register!(u8, u16, u32);
+
+pub trait BitStore: Sized + Debug {
+    /// The register type that the implementor describes.
+    type Mem: BitRegister + Into<Self>;
+}
+
+macro_rules! store {
+    ($($t:ty),+ $(,)?) => { $(
+        impl BitStore for $t {
+            type Mem = Self;
+        }
+    )+ };
+}
+
+store!(u8, u16, u32,);
+
+#[repr(C)]
+pub struct BitVec<T>
+where
+    T: BitStore,
+{
+    /// Region pointer describing the live portion of the owned buffer.
+    pointer: ptr::NonNull<T>,
+    /// Allocated capacity, in elements `T`, of the owned buffer.
+    capacity: usize,
+}
+
+impl<T> BitVec<T>
+where
+    T: BitStore,
+{
+    pub fn new() -> Self {
+        let pointer = ptr::NonNull::<T>::new(ptr::null_mut()).unwrap();
+
+        BitVec { pointer, capacity: 10 }
+    }
+
+    pub fn clear(&mut self) {
+        unsafe {
+            self.set_len(0);
+        }
+    }
+
+    #[inline]
+    pub unsafe fn set_len(&mut self, new_len: usize) {}
+
+    fn with_vec<F, R>(&mut self, func: F) -> R
+    where
+        F: FnOnce(&mut ManuallyDrop<Vec<T::Mem>>) -> R,
+    {
+        let cap = self.capacity;
+        let elts = 10;
+        let mut vec = ManuallyDrop::new(unsafe { Vec::from_raw_parts(ptr::null_mut(), elts, cap) });
+        let out = func(&mut vec);
+
+        out
+    }
+}
+
+impl<T> Drop for BitVec<T>
+where
+    T: BitStore,
+{
+    #[inline]
+    fn drop(&mut self) {
+        //  The buffer elements do not have destructors.
+        self.clear();
+        //  Run the `Vec` destructor to deällocate the buffer.
+        self.with_vec(|vec| unsafe { ManuallyDrop::drop(vec) });
+    }
+}
+
+fn main() {
+    let bitvec = BitVec::<u32>::new();
+}