message: Fix Allocative for Vec2
  Summary:
  Contents was declared inline, not as pointee.
  This resulted in slightly incorrect size estimation of containing structs (and also warnings).
diff: @@ -386,8 +386,11 @@ impl<K: Allocative, V: Allocative> Allocative for Vec2<K, V> {
  fn visit<'a, 'b: 'a>(&self, visitor: &'a mut Visitor<'b>) {
  let mut visitor = visitor.enter_self_sized::<Self>();
  if self.cap != 0 {
  - let mut visitor = visitor.enter_unique(
  - allocative::Key::new("ptr"),
  + let mut visitor =
  + visitor.enter_unique(allocative::Key::new("ptr"), mem::size_of::<*const ()>());
  + {
  + let mut visitor = visitor.enter(
  + allocative::Key::new("data"),
  Vec2Layout::<K, V>::new(self.cap).layout.size(),
  );
  for (k, v) in self {
  @@ -398,6 +401,8 @@ impl<K: Allocative, V: Allocative> Allocative for Vec2<K, V> {
  }
  visitor.exit();
  }
  + visitor.exit();
  + }
  }
  #[cfg(test)]
  