[SR-426] Memory leak with enum containing class, downcast to Any.Type #43043
Description
| Previous ID | SR-426 |
| Radar | None |
| Original Reporter | austin (JIRA User) |
| Type | Bug |
| Status | Resolved |
| Resolution | Done |
Environment
Building on OS X 10.11.2, revision 73872e5.
Additional Detail from JIRA
| Votes | 0 |
| Component/s | Standard Library |
| Labels | Bug, NotOptimizedOnly, Runtime |
| Assignee | jder (JIRA) |
| Priority | Medium |
md5: 66dcf74255f01d0bc1c3c7eded17fdfe
blocks:
- SR-88 Remove old mirrors
Issue Description:
The following code appears to produce a memory leak. When it is run, the relevant class's `deinit` is never called:
class BasicClass {
let a : Int
init(_ a: Int) {
print("BasicClass being init'ed with value \(a)")
self.a = a
}
deinit {
print("BasicClass being deinit'ed with value \(a)")
}
}
enum Bar<T> {
case First(T)
}
enum Baz<T, U> {
case First(T), Second(U), Third, Fourth
}
func doSomething() {
let myThing : Any = Bar.First(BasicClass(10))
// bad behavior also happens with multi-payload generic enums
// bad behavior also happens with a tuple, like "(1, 2, BasicClass(10))"
// bad behavior does not happen with just a bare "BasicClass(10)"
// A:
if let foo = myThing as? Any.Type {
print("myThing is a metatype")
}
}
doSomething()In particular, the thing that causes trouble is the conditional downcast to Any.Type (marked by the comment 'A'). If the if-let statement is removed, the init and deinit run properly. If the if-let statement is present, only the init runs properly.
A downcast to a non-metatype seems to work fine. I have not tried downcasting to other metatypes.