How do you use Universal Function Call Syntax  with slices?  []::<i32>::len(&[1]) and similar variants all give a syntax error.   As a (very silly) use case, let’s say that I have defined a trait like this:  trait MyLen {     fn len(&self) -> usize; }  impl<T> MyLen for T {     fn len(&self) -> usize { 0 } }  And then want to know the actual length of a slice I have. Using [1,2,3].len() will just use my custom len method and always return 0. Both [i32]::len and []::len are syntax errors, with th...