Not sure why the earlier version even compiled; the `Iterator.Element` types need to match up for most of these operations, and the `Iterator` types themselves need to match for some.
I think the complexity of these condition extensions is unneeded, and may be vestigial from a time when the compiler was less cooperative. Test this theory using CI
Eliminate all of the redundant conformance constraints in the standard
library that were identified by the newly-introduced warning for
redundant, explicitly-specified conformances.
Adds the runtime implementation for copy-on-write existentials. This support is
enabled if SWIFT_RUNTIME_ENABLE_COW_EXISTENTIALS is defined. Focus is on
correctness -- not performance yet.
Don't use allocate/deallocate/projectBuffer witnesses for globals in cow
existential mode.
Use SWIFT_RUNTIME_ENABLE_COW_EXISTENTIALS configuration to set the default for
SILOptions.
This includes an IRGen fix to use the right projection in
emitMetatypeOfOpaqueExistential if SWIFT_RUNTIME_ENABLE_COW_EXISTENTIALS is set.
Use unknownRetain instead of native retain in dynamicCastToExistential.
Calling drop(while: ) after prefix() on a pure Sequence loses the
prefix, because in the internal drop(while: ) override grabs the
underlying base iterator from _PrefixSequence and wraps it in a
_DropWhileSequence.
Previously often times when casting a value, we would just pass along the
cleanup of the uncasted value. With semantic SIL this is no longer correct since
the cleanup now needs to be on the cast result.
This caused problems for certain usages of Builtin.castToNativeObject(...) by
the stdlib. Specifically, the stdlib was using this on AnyObject values that
were not necessarily native. Since we were recreating the cleanup on the native
value, a swift native release was being used =><=.
In this commit I solve this problem by:
1. Adding an assert in Builtin.castToNativeObject(...) that ensures that any value
passed to Builtin.castToNativeObject() is known conservatively to use swift
native reference counting.
2. I changed all uses where we do not have a precondition of a native ref
counting type to use Builtin.castToUnknownObject(...).
3. I added a new Builtin called Builtin.unsafeCastToNativeObject(...) that does
not have the compile time check. I used this to rewrite callsites in the stdlib
where we know via preconditions that an AnyObject will dynamically always be
native.
rdar://29791263
Conforming types already provide the static bitWidth property. Instance
one can be implemented in a protocol extension.
Resolves: <rdar://problem/30186638>
