This should have been done for Swift 4.2 according to SE-0204, but
better later than never. Deprecating these methods as of Swift 5.0.
Also modfying the tests to check for the deprecation message.
Fixes: <rdar://problem/43694210>
* Obsolete ModifierSlice typealiases in 5.0
* Obsolete *Indexable in 5.0
* Obsolete IteratorOverOne/EmptyIterator in 5.0
* Obsolete lazy typealiases in 5.0
* Drop .characters from tests
* Obsolete old literal protocols in 5.0
* Obsolete Range conversion helpers in 5.0
* Obsolete IndexDistance helpers in 5.0
* Obsolete Unsafe compat helpers in 5.0
* Obsolete flatMap compatibility helper in 5.0
* Obsolete withMutableCharacters in 5.0
* Obsolete customPlaygroundQuickLook in 5.0
* Deprecate Zip2Sequence streams in 5.0
* Replace * with swift on lotsa stuff
* Back off obsoleting playground conformances for now
Remove many of the implementations of obsoleted String functionality
by replacing it with unreachable. A few remain temporarily until the
Foundation overlay can be updated.
Also, update TestJSONEncoder.swift off of deprecated functionality.
* Update std lib to Swift 5.0
* Disable Unicode.* warnings for now
* Slow path to resiliently handle the case where an unknown rounding rule is passed
* Remove resilience from Encoding/DecodingError (which should only happen on slow paths anyway)
* internal typealiases now need @usableFromInline
* Force inlining on Array._owner.get
We still had unavailable versions of these for floating-point types
only. We shouldn't need to keep these around, and can instead just
emit a helpful diagnostic for anyone that attempts to use them.
Unfortunately I don't see any way for the diagnostic to produce an
actual fix-it, so it just suggests '+= 1' or '-= 1' without actually
producing a fix.
