Lt still slow?

See below for some text from the datastructures.jl documentation (which I wrote last year). I'm wondering whether the statement about the performance hit from using Lt rather than a customized order type is still accurate for 0.5 and 0.6, in which the type system for functions has been revamped. I can try some performance tests if the consensus is that the current documentation is inaccurate.

A second minor documentation issue is that the entry in the table of contents for the sorted containers should probably be "Sorted containers" rather than "Overview of sorted containers".

Thanks,
Steve

---- quote from the documentation begins here

The simplest approach is to define an ordering object of the form Lt(my_isless), where Lt is a built-in type (see ordering.jl) and my_isless is the user’s comparison function. In the above example, the ordering object would be:

  Lt((x,y) -> isless(lowercase(x),lowercase(y)))

The ordering object is indicated in the above list of constructors in the o position (see above for constructor syntax).

This approach suffers from a performance hit (10%-50% depending on the container) because the compiler cannot inline or compute the correct dispatch for the function in parentheses, so the dispatch takes place at run-time.

Start with the datastructures.jl documentation and ordering.jl, then verify whether the stated performance hit for Lt remains accurate in Julia 0.5 and 0.6. Use performance tests to confirm the documentation claim, and check the sorted containers table-of-contents entry. Done means the performance wording reflects the results and the entry is renamed if appropriate.