This necessary for ensuring the property that String doesn't keep
inaccessible memory alive. For example, before this change,
String(s.dropFirst().unicodeScalars)
would compile and produce a String that owned inaccessible memory.
Now it no longer compiles.
String's view's SubSequences are the same as the Substring's
view. E.g. String.UnicodeScalarView.SubSequence is
Substring.UnicodeScalarView.
New compatibility inits added, to work around the fact that many
previously failable initializers are now non-failable.
This is a step along the way toward handling backward-compatiblity of UTF8View
slicing and preventing inadvertent creation of String instances that keep
inaccessible memory alive.
I failed to merge the upstream changes to swift-corelibs-foundation at the same
time as I merged that #9806, and it broke on linux. Going to get it right this
time.
EmptyCollection was changed a while ago to use _debugPrecondition checks in the
accesses being tested that fail in optimize mode. Change the test to only expect
a failure in debug mode.
rdar://31897334
This reverts commit
ecfa406fc5, which was reinstating
3c5b393e0c.
It does not revert one test change from that commit, because
inexplicably one of the tests is still failing, probably due to some
other changes that have happened since. I'm leaving a ticket open to
investigate.
I've added one of the new cases that is failing as a result of this
change.
This is being reverted not because of bugs in this particular commit,
but because it seems to be exposing other bugs in the type checker that
are resulting in source compatibility problems. We need to shake these
other bugs out of the type checker before bringing this change back.
* Give Sequence a top-level Element, constrain Iterator to match
* Remove many instances of Iterator.
* Fixed various hard-coded tests
* XFAIL a few tests that need further investigation
* Change assoc type for arrayLiteralConvertible
* Mop up remaining "better expressed as a where clause" warnings
* Fix UnicodeDecoders prototype test
* Fix UIntBuffer
* Fix hard-coded Element identifier in CSDiag
* Fix up more tests
* Account for flatMap changes
Like NSObject, CFType has primitive operations CFEqual and CFHash,
so Swift should allow those types to show up in Hashable positions
(like dictionaries). The most general way to do this was to
introduce a new protocol, _CFObject, and then have the importer
automatically make all CF types conform to it.
This did require one additional change: the == implementation that
calls through to CFEqual is in a new CoreFoundation overlay, but the
conformance is in the underlying Clang module. Therefore, operator
lookup for conformances has been changed to look in the overlay for
an imported declaration (if there is one).
This re-applies 361ab62454, reverted in
f50b1e73dc, after a /very/ long interval
where we decided if it was worth breaking people who've added these
conformances on their own. Since the workaround isn't too difficult---
use `#if swift(>=3.2)` to guard the extension introducing the
conformance---it was deemed acceptable.
https://bugs.swift.org/browse/SR-2388
