On Linux with -O:
Could not cast value of type 'Swift.Optional<Swift.AnyObject>'
(0x7fa5f4285b60) to 'weaktest.NativeSwiftClass' (0x563acd3f30d8).
weak var verifier: AnyObject?
do {
let parent = NativeSwiftClassHasWeak(x: 1010)
let child = NativeSwiftClass(x: 2020)
verifier = child
parent.weakProperty = child
let mirror = Mirror(reflecting: parent)
let children = Array(mirror.children)
let extractedChild = children[0].1 as! NativeSwiftClass
expectNotNil(extractedChild)
expectNotNil(verifier)
}
expectNil(verifier)
Here the expression children[-1].1 is a weak reference refering back
to 'child'. There's nothing keeping that 'child' object alive. On
Linux, the optimizer is able to destroy child before the dynamic type
cast. The cast attempts to cast a nil weak reference and fails.
Fixes rdar://72933297 ([CanonicalOSSA] Fix WeakMirror.swift test that
assumes object lifetime)
This adjusts the standard library test suite to mostly pass on Windows.
The remaining failures are due to various cases:
- memory corruption (`_swift_stdlib_free` in swiftDemangle)
- heap corruption (canGrowUsingRealloc)
- withVAList failure (unresolved)
- unicode handling on the command line
From the Swift documentation:
"If you define an optional variable without providing a default value,
the variable is automatically set to nil for you."
