In Swift 3, we had a bug where you could provide argument labels
to a function call taking a single Any parameter, even if the
parameter did not have a label.
This mostly worked (with asserts off!) but in fact it would crash
in SILGen if you were calling an enum case constructor.
Since this 'feature' has been promoted from 'works on accident' to
'still a hack but guarded by Swift 3 mode and exists on purpose',
fix the crash, even though Swift 3 could not compile the code in
question.
Also add a Swift 3 mode check to the earlier SILGen hack, so that
when/if we remove Swift 3 mode it will be obvious that this code is
now dead too.
In Swift 3.0.1, argument labels are ignored when calling a function
having a single parameter of 'Any' type. That is, if we have:
func foo(_: Any) {}
Both of the following were accepted in a no-assert build (an assert
build would crash, but the GM builds of Xcode ship with asserts off):
foo(123)
foo(data: 123)
This behavior was fixed by 578e36a7e1,
but unfortunately we have to revert to the old behavior *and* defeat
the assertion when in Swift 3 mode.
Swift 4 mode still has the correct behavior, where the second call
'foo(data: 123)' produces a diagnostic.
Now, I have to pour myself a strong drink to forget this ever happened.
Fixes <rdar://problem/28952837>.
There's a general problem where a SubscriptExpr has an argument
that's a LoadExpr loading a tuple from an lvalue. For some reason
we don't construct the ParenExpr in this case, which confused
CSDiag.
Also, in Swift 3 mode, add a total hack to fudge things in
matchCallArguments() in the case where we erroneously lost
ParenType sugar.
Fix matchTypes() to be more careful about stripping off ParenType
sugar, in order to match the behavior outlined in SE-0110.
Note that the new logic only executes in Swift 4 mode; there's
no functional change here in Swift 3 mode.
This makes a second copy of the tuple_arguments test:
- Compatibility/tuple_arguments is a test for Swift 3, updated to
note differences with Swift 3.
- Constraints/tuple_arguments has been updated for the new Swift 4
mode behavior.
Fixes <rdar://problem/27383557>.
