stack info: objc Thread 1 Queue : com.apple.main-thread (serial) #0 0x00007fff2cca2d75 in swift_isUniquelyReferenced_nonNull_native () #1 0x00007fff4263ec1c in specialized Array._makeUniqueAndReserveCapacityIfNotUnique() () #2 0x00007fff42abe6ad in PlatformDocumentController.createDocumentClassIfNeeded(_:) () #3 0x00007fff42abdf97 in PlatformDocumentController.init(formulas:) () #4 0x00007fff4290d0ce in AppDelegate.applicationWillFinishLaunching(_:) () #5 0x00007fff4290d880 in @objc AppDelegate.applicationWillFinishLaunching(_:) () #6 0x00007fff20638fec in __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ () #7 0x00007fff206d489b in ___CFXRegistrationPost_block_invoke () #8 0x00007fff206d480f in _CFXRegistrationPost () #9 0x00007fff20609bde in _CFXNotificationPost () #10 0x00007fff21378abe in -[NSNotificationCenter postNotificationName:object:userInfo:] () #11 0x00007fff22e52931 in -[NSApplication finishLaunching] () #12 0x00007fff22e5253a in -[NSApplication run] () #13 0x00007fff22e2696f in NSApplicationMain () #14 0x00007fff4261a9f4 in specialized runApp(_:) () #15 0x00007fff42eb1792 in runAppA(_:) () #16 0x00007fff42a3009d in static App.main() () crash info: objc SwiftUI`merged generic specialization SwiftUI.HostPreferencesCombiner.Child of Swift.Array._makeUniqueAndReserveCapacityIfNotUnique() - ():   0x7fff4263ec00 +0: pushq %rbp   0x7fff4263ec01 +1: movq  %rsp, %rbp   0x7fff4263ec04 +4: pushq %r15   0x7fff4263ec06 +6: pushq %r14   0x7fff4263ec08 +8: pushq %rbx   0x7fff4263ec09 +9: pushq %rax   0x7fff4263ec0a +10: movq  %rdx, %r14   0x7fff4263ec0d +13: movq  %rsi, %r15   0x7fff4263ec10 +16: movq  %rdi, %rbx   0x7fff4263ec13 +19: movq  (%r13), %rdi   0x7fff4263ec17 +23: callq 0x7fff430225a8      ; symbol stub for: swift_isUniquelyReferenced_nonNull_native 0x7fff4263ec1c +28: testb %al, %al   0x7fff4263ec1e +30: je   0x7fff4263ec2b      ; +43   0x7fff4263ec20 +32: addq  $0x8, %rsp   0x7fff4263ec24 +36: popq  %rbx   0x7fff4263ec25 +37: popq  %r14   0x7fff4263ec27 +39: popq  %r15   0x7fff4263ec29 +41: popq  %rbp   0x7fff4263ec2a +42: retq     0x7fff4263ec2b +43: movq  (%r13), %rax   0x7fff4263ec2f +47: movq  0x10(%rax), %rsi   0x7fff4263ec33 +51: incq  %rsi   0x7fff4263ec36 +54: pushq $0x1   0x7fff4263ec38 +56: popq  %rdx   0x7fff4263ec39 +57: xorl  %edi, %edi   0x7fff4263ec3b +59: movq  %rbx, %rcx   0x7fff4263ec3e +62: movq  %r15, %r8   0x7fff4263ec41 +65: callq *%r14   0x7fff4263ec44 +68: jmp  0x7fff4263ec20      ; +32   0x7fff4263ec46 +70: nopw  %cs:(%rax,%rax) swiftui code swift DocumentGroup(newDocument: {       return MyFileDocument(self.home.create())     }()) { file in       if let m = home.open(file) {         MainView(vModel: m ).background(           HostingWindowFinder { (window) in             guard let window = window else {               return             }             window.delegate = home             print(window)           }         )       } else {         Text("ERROR")       }     }.commands {       SaveCommands()       SidebarCommands()     }