[SR-15774] Error "the compiler is unable to type-check this expression in reasonable time" for what should be a fairly trivial expression

[swift-ci]

Previous ID	SR-15774
Radar	None
Original Reporter	aaargh! (JIRA User)
Type	Bug

Environment

IDE/Compiler: XCode version 13.2.1 (13C100), Apple Swift version 5.5.2 (swiftlang-1300.0.47.5 clang-1300.0.29.30)

OS: macOS 12.1

Arch: Arm64

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	None
Priority	Medium

md5: d350d8f547493a4f867fe9cd4741de79

Issue Description:

The following code causes the compiler to fail with an "the compiler is unable to type-check this expression in reasonable time" error.

fileprivate extension URLSessionTaskTransactionMetrics {
    
    var timeOfLastEvent: Date? {
        responseEndDate ?? responseStartDate ?? requestEndDate ?? requestStartDate ?? connectEndDate ?? secureConnectionEndDate ?? secureConnectionStartDate ?? connectStartDate ?? domainLookupEndDate ?? domainLookupStartDate ?? fetchStartDate
    }
}

All properties here are of type Date?

[slavapestov]

Still too complex on main. I'll add a test case.