std.algorithm sort() and reverse() confusion

[Paul via Digitalmars-d-learn]

On Friday, 30 January 2015 at 16:21:24 UTC, Kagamin wrote:
> writeln("Sorted, reversed: ", retro(sort(myVals)));
> ?

Or...

writeln("Reverse sorted: ", sort!("a > b")(vals));

but I still don't understand the original 'error'.