This reverts commit 3e932c075d.
The compiler does not support @_alwaysEmitIntoClient properties
specially wrt property descriptors. The revert commit would introduce an
ABI incompatability when a keypath to Array.first is formed:
let greetings = ["hello", "hola"]
let count = greetings[keyPath: \[String].first?.count]
Runmning on an older runtime would lead to linker errors against $sSa5firstxSgvpMV
the property descriptor for Array.first.
rdar://58484319
This makes Array.first much small and more efficient.
Without this, Array.first compiled down to RandomAccessCollection.first, which ended up in pretty unefficient code.
rdar://problem/46291397
There were 2 functions to output argument list. Consolidate them and
consistently use it from every call like production (i.e. function call,
constructor call, enum with associated values, subscript)
* Handle completion in 'parseExprKeyPath()' instead of
'parseExprPostfixSuffix()'.
* Fix a crash for implicit type keypath. e.g. '\.path.<complete>'. (SR-8042).
* Use 'completeExprKeyPath()' callback.
* Implement completion without '.'. e.g. '\Ty.path<complete>'
* Improved handling for 'subscript' in completion.
* Improved handling for optional unwrapping in completion.
https://bugs.swift.org/browse/SR-8042
rdar://problem/41262612
