Macro smallvec 

macro_rules! smallvec {
    (@one $x:expr) => { ... };
    () => { ... };
    ($elem:expr; $n:expr) => { ... };
    ($($x:expr),+$(,)?) => { ... };
}

Creates a [SmallVec] containing the arguments.

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, smallvec![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.