* Eradicate IndexDistance associated type, replacing with Int everywhere
* Consistently use Int for ExistentialCollection’s IndexDistance type.
* Fix test for IndexDistance removal
* Remove a handful of no-longer-needed explicit types
* Add compatibility shims for non-Int index distances
* Test compatibility shim
* Move IndexDistance typealias into the Collection protocol
* Refactor Indices and Slice to use conditional conformance
* Replace ReversedRandomAccessCollection with a conditional extension
* Refactor some types into struct+extensions
* Revise Slice documentation
* Fix test cases for adoption of conditional conformances.
* [RangeReplaceableCollection] Eliminate unnecessary slicing subscript operator.
* Add -enable-experimental-conditional-conformances to test.
* Gruesome workaround for crasher in MutableSlice tests
After changes to stdlib and type-checker related to removing
of the `_Strideable` it's now possible to properly support
iterator types for *ClosedRange without any workarounds.
Resolves: rdar://problem/25584401
Using && here causes us to go down a SILGen path that guarantees that self will
be evaluated over the entire && expression instead of just the LHS. This cause
the uniqueness check to always return false at -Onone. At -O, the optimizer is
smart enough to remove this issue.
rdar://33358110
For Swift 3 / 4:
Deprecate the spelling "ImplicitlyUnwrappedOptional", emitting a warning
and suggesting "!" in places where they are allowed according to
SE-0054.
In places where SE-0054 disallowed IUOs but we continued to accept them
in previous compilers, emit a warning suggesting "Optional" or "?" as
an alternative depending on context and treat the IUO as an Optional,
noting this in the diagnostic.
For Swift 5:
Treat "ImplicitlyUnwrappedOptional" as an error, suggesting
"!" in places where they are allowed by SE-0054.
In places where SE-0054 disallowed IUOs, emit an error suggestion
"Optional" or "?" as an alternative depending on context.
Consider different overload choices for the same location in evaluation
order, this makes overload resolution more predictable because it's going
to follow expression bottom-up, that prevents situations when some
expressions are considered ambigious because choices taken further up
equate the score, instead each level is given distinct weight
based on evaluation order.
Resolves: rdar://problem/31888810
The optimized-build behavior of UnsafeBufferPointer bounds/overflow
checking cannot be tested. The standard library always compiles with debug
checking enabled, so the behavior of the optimized test depends on whether
the inlining heuristics decide to inline these methods. To fix this, we need
a way to force @_inlineable UnsafeBufferPointer methods to be emitted inside
the client code, and thereby subject the stdlib implementation to the test
case's compile options.
