Remove redundant JoinInput impl

Author: ecstatic-morse

src/join.rs

@@ -196,29 +196,3 @@ impl<'me, Tuple> JoinInput<'me, Tuple> for &'me Relation<Tuple> {
         f(&self.elements)
     }
 }
-
-impl<'me, Tuple> JoinInput<'me, (Tuple, ())> for &'me Relation<Tuple> {
-    type RecentTuples = &'me [(Tuple, ())];
-
-    fn recent(self) -> Self::RecentTuples {
-        &[]
-    }
-
-    fn for_each_stable_set(self, mut f: impl FnMut(&[(Tuple, ())])) {
-        use std::mem;
-        assert_eq!(mem::size_of::<(Tuple, ())>(), mem::size_of::<Tuple>());
-        assert_eq!(mem::align_of::<(Tuple, ())>(), mem::align_of::<Tuple>());
-
-        // SAFETY: https://rust-lang.github.io/unsafe-code-guidelines/layout/structs-and-tuples.html#structs-with-1-zst-fields
-        // guarantees that `T` is layout compatible with `(T, ())`, since `()` is a 1-ZST. We use
-        // `slice::from_raw_parts` because the layout compatibility guarantee does not extend to
-        // containers like `&[T]`.
-        let elements: &'me [Tuple] = self.elements.as_slice();
-        let len = elements.len();
-
-        let elements: &'me [(Tuple, ())] =
-            unsafe { std::slice::from_raw_parts(elements.as_ptr() as *const _, len) };
-
-        f(elements)
-    }
-}