Comment by Rob Nash (JIRA)

FYI

The protocol 'CardableScene' currently shows 'redundant layout constraint" warning, as explained here

https://bugs.swift.org/browse/SR-6265?focusedCommentId=31224&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-31224

However, it has been suggested in the comments that this issue is not related.

@swift-ci create

Do you have a complete project where this reproduces? That'll make it easier to be sure we're looking at the same thing.

Comment by Rob Nash (JIRA)

Ye sure @belkadan project attached. Run the workspace on an iPhone simulator of your choice and take a look at DanceClassViewController.swift

override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.title = "Class"
} [^Archive.zip] 

It looks like that one isn't the problem one, but breaking at Card.swift:17 lets me try the "p scene.showsNavigationBar" that causes the problem. Accessing plain Objective-C methods like "p scene.view" also produces this error.

(Thanks!)

Comment by Alex Reilly (JIRA)

Any updates on this? Still experiencing it on the current Xcode (9.3)

Full error that I'm experiencing:

(lldb) po newDatasource.values
objc[60841]: Method cache corrupted. This may be a message to an invalid object, or a memory error somewhere else.
objc[60841]: receiver 0x7b14000f0230, SEL 0x10fef5a70, isa 0x111f6bf98, cache 0x111f6bfa8, buckets 0x7b1400101030, mask 0x3, occupied 0x1
objc[60841]: receiver 0 bytes, buckets 80 bytes
objc[60841]: selector 'release'
objc[60841]: isa '_TtGCs13ManagedBufferGVs17_HeapBufferHeaderVs18_StringBufferIVars_Vs6UInt16_'
objc[60841]: Method cache corrupted. This may be a message to an invalid object, or a memory error somewhere else.
expression produced error: warning: couldn't get required object pointer (substituting NULL): Couldn't load 'self' because its value couldn't be evaluated

error: Execution was interrupted, reason: signal SIGABRT.
The process has been returned to the state before expression evaluation.

That's probably a different issue, Alex. Can you file that separately with your own reproducer?

This bug is an unfortunate series of events. I plan to work on this 🙂

(I have ideas on how to fix this, it's just not trivial).

I never got around to this, but I have ideas on how to fix. It would be a good starter bug.

Comment by Andrey Yakushev (JIRA)

Same problem in Xcode 11.1, during XCTests (sorry, can't show code - NDA). But looks very close (but with Foundation classes instead of UIKit)

The radar linked with this issue is marked as fixed — Is this accurate?