please rewrite a sentence about types in the manual #23967
Description
The following sentence appears at the end of the 3rd paragraph of the chapter called "Types" in the manual. When I read it several years ago as a Julia newbie, I misunderstood what it meant and got a wrong impression of how types work:
"Doing so [gradually introducing type annotations] will typically increase both the performance and robustness of these systems, and perhaps somewhat counterintuitively, often significantly simplify them."
I mistakenly thought that this sentence meant that the myplus example (appearing later in the section, but was not in the manual when I first read it) would be more efficient if both x and y were explicitly typed.
Now that I am more experienced, I still don't know what the above sentence means, but it is still a high-visibility sentence for newbies. AFAIK, the main reasons to introduce type annotations in function specifications are: (1) to guide the multiple dispatch, (2) to catch programmer errors, (3) to improve human readability. None of these three directly relates to performance, robustness or simplicity. So I would like to suggest that the original author rewrite the sentence or else delete it.