Intelligent prompt issue of Swift

Number:rdar://49843572 Date Originated:April 12 2019, 3:50 PM
Status: Resolved:
Product:Xcode Product Version:10.2
Classification: Reproducible:Always
There always has tips issue when I typing in variableness's initialization close and use  another close inside, it display <<error type>> in the inside close when I typing variableness, even the bulid system already finish all job and can show warning about it type  

Steps to Reproduce:
create a variableness and initialize it with a close like this(here use a third party framework: snapkit):
	lazy var imageView: UIImageView = {
		let view = UIImageView()
		view.snp.makeConstraints { (make) in
		return view

Expected Results:
in the close of view.snp.makeConstraints,"make" can be prompted rightly , and it's property "width" can be prompted, and the "equalTo" too.

Actual Results:
"make" is prompted "<<error type>>" in Xcode 10.1, or prompted nothing in Xcode 10.2, and "width", "equalTo" never be prompted.

and also I try to bring a configurator to UIResponder:
protocol ViewConfigProtocol {}
extension ViewConfigProtocol where Self: UIResponder {
	func config(_ config: ((Self) -> Void)) -> Self {
		return self
extension UIResponder: ViewConfigProtocol { }

so I can initialize a variableness like this: 
	lazy var shareImageContentView = UIScrollView().config { (view) in
However it does't work either, the "view" is  prompted wrongly and "alpha" never be prompted.
Interestingly, the build system can show tips "Expression of type 'CGFloat' is unused" rightly

By the way, this legacy bug already existed when I use Swift 2 years ago. And Objective-C basically has  similar  issue witch still did't been fixed all these years....


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