[SR-8964] Type check operator (is) fails for Any! variable holding an Error (struct) value

[swift-ci]

Previous ID	SR-8964
Radar	rdar://problem/45217461
Original Reporter	wojciechczerski (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Environment

Xcode 10.0 (10A255), Swift 4.2

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, Runtime
Assignee	@tbkka
Priority	Medium

md5: 942adf7e130c74daa296f6ca84a5bcbc

relates to:

• SR-4552 Implicitly Unwrapped Optional after casting to Any, can't be casted to Protocol it conforms to

Issue Description:

In the following code the "b is Error" incorrectly returns false though the b variable holds an Error value.

struct MyError: Error { }

let a: Any! = MyError()
let b: Any = a
b is Error // false 

The result of the type check should be true. This issue might be related to SR-4552.

[AnnaZaks]

CC @jckarter
@swift-ci create

[tbkka]

#33561 should fix this for the non-optimized case (where the cast is being handled by the runtime). There may still be issues with optimized casts, though.

[tbkka]

This now appears to be fixed for both debug and release builds.