/// Note that unlike array expressions this syntax supports all elements
/// which implement `Clone` and the number of elements doesn't have to be
/// a constant.
+///
+/// This will use `clone()` to duplicate an expression, so one should be careful
+/// using this with types having a nonstandard `Clone` implementation. For
+/// example, `vec![Rc::new(1); 5]` will create a vector of five references
+/// to the same boxed integer value, not five references pointing to independently
+/// boxed integers.
#[cfg(not(test))]
#[macro_export]
#[stable(feature = "rust1", since = "1.0.0")]