The rule changes are as follows:
* All functions (introduced with the 'func' keyword) have argument
labels for arguments beyond the first, by default. Methods are no
longer special in this regard.
* The presence of a default argument no longer implies an argument
label.
The actual changes to the parser and printer are fairly simple; the
rest of the noise is updating the standard library, overlays, tests,
etc.
With the standard library, this change is intended to be API neutral:
I've added/removed #'s and _'s as appropriate to keep the user
interface the same. If we want to separately consider using argument
labels for more free functions now that the defaults in the language
have shifted, we can tackle that separately.
Fixes rdar://problem/17218256.
Swift SVN r27704
Curried function parameters (i.e., those past the first written
parameter list) default to having argument labels (which they always
have), but any attempt to change or remove the argument labels would
fail. Use the fact that we keep both the argument labels and the
parameter names in patterns to generalize our handling of argument
labels to address this problem.
The IDE changes are due to some positive fallout from this change: we
were using the body parameters as labels in code completions for
subscript operations, which was annoying and wrong.
Fixes rdar://problem/17237268.
Swift SVN r24525
