#expect crashes w/ EXC_BAD_ACCESS on collections of length greater than 2 where children refer to parent

[dleavitt]

Description

I have a class Coll with a property items that's an array of Items.

These Items can have a weak reference back to their Coll. If at least three of them do, a failed expectation about the Coll or one of the Items will cause a crash with EXC_BAD_ACCESS.

I believe the crash is caused when generating the description of the expectation e.g. Expectation failed: (subject → SwiftExpectReproTests.Coll) == nil

Looks like infinite recursion?

Reproduction

import Testing

// minimal reproduction
@Test func testSimplestRepro() {
    let collection = Coll([Item("a"), Item("b"), Item("c")])
    for item in collection.items { item.collection = collection }
    #expect(collection == nil) // EXC_BAD_ACCESS
}

// what crashes, what doesn't
@Test func testFailureScenarios() {
    let subject = Coll([Item("a"), Item("b"), Item("c")])

    let sameLength = Coll([Item("c"), Item("a"), Item("b")])

    #expect(subject == sameLength) // expectation fails but doesn't crash
    #expect(subject == nil) // expectation fails but doesn't crash

    // two items is fine
    subject.items[0].collection = subject
    subject.items[1].collection = subject
    #expect(subject == sameLength) // expectation fails but doesn't crash
    // but once we add a third item...
    subject.items[2].collection = subject

    let equal = Coll([Item("a"), Item("b"), Item("c")])
    #expect(subject == equal) // works fine, doesn't need to print expectation

    #expect(subject == sameLength, "Nope") // crashes with EXC_BAD_ACCESS. Message doesn't help.
    #expect(subject.items == sameLength.items) // crashes
    #expect(subject == nil) // crashes
    #expect(subject.items[0] == nil) // crashes

    let diffLength = Coll([Item("a"), Item("b"), Item("c"), Item("d")])
    #expect(subject == diffLength) // crashes
}

class Coll: Equatable { // equatable isn't actually needed to repro
    var items: [Item]
    init(_ items: [Item] = []) { self.items = items }
    static func == (lhs: Coll, rhs: Coll) -> Bool {
        guard lhs.items.count == rhs.items.count else { return false }
        return lhs.items == rhs.items
    }
}

class Item: Equatable {
    var id: String
    weak var collection: Coll? // weak vs strong doesn't make a difference
    init(_ id: String) { self.id = id }
    static func == (lhs: Item, rhs: Item) -> Bool { lhs.id == rhs.id }
}

Stack dump

* thread #2, queue = 'com.apple.root.user-initiated-qos.cooperative', stop reason = EXC_BAD_ACCESS (code=2, address=0x16fe03c50)
    frame #0: 0x00000001a6b7bec8 libswiftCore.dylib`swift_getTypeByMangledNameImpl(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<void const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 72
    frame #1: 0x00000001a6b75d70 libswiftCore.dylib`swift_getTypeByMangledName + 836
    frame #2: 0x00000001a6b91028 libswiftCore.dylib`swift::_checkGenericRequirements(__swift::__runtime::llvm::ArrayRef<swift::GenericParamDescriptor>, __swift::__runtime::llvm::ArrayRef<swift::TargetGenericRequirementDescriptor<swift::InProcess>>, __swift::__runtime::llvm::SmallVectorImpl<void const*>&, std::__1::function<void const* (unsigned int, unsigned int)>, std::__1::function<void const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 1100
    frame #3: 0x00000001a6b79410 libswiftCore.dylib`_gatherGenericParameters(swift::TargetContextDescriptor<swift::InProcess> const*, __swift::__runtime::llvm::ArrayRef<swift::MetadataOrPack>, swift::TargetMetadata<swift::InProcess> const*, __swift::__runtime::llvm::SmallVectorImpl<unsigned int>&, __swift::__runtime::llvm::SmallVectorImpl<void const*>&, swift::Demangle::__runtime::Demangler&) + 2004
    frame #4: 0x00000001a6b846d8 libswiftCore.dylib`(anonymous namespace)::DecodedMetadataBuilder::createBoundGenericType(swift::TargetContextDescriptor<swift::InProcess> const*, __swift::__runtime::llvm::ArrayRef<swift::MetadataOrPack>, swift::MetadataOrPack) const + 248
    frame #5: 0x00000001a6b80fb4 libswiftCore.dylib`swift::Demangle::__runtime::TypeDecoder<(anonymous namespace)::DecodedMetadataBuilder>::decodeMangledType(swift::Demangle::__runtime::Node*, unsigned int, bool) + 9904
    frame #6: 0x00000001a6b80bf4 libswiftCore.dylib`swift::Demangle::__runtime::TypeDecoder<(anonymous namespace)::DecodedMetadataBuilder>::decodeMangledType(swift::Demangle::__runtime::Node*, unsigned int, bool) + 8944
    frame #7: 0x00000001a6b7bcc0 libswiftCore.dylib`swift_getTypeByMangledNodeImpl(swift::MetadataRequest, swift::Demangle::__runtime::Demangler&, swift::Demangle::__runtime::Node*, void const* const*, std::__1::function<void const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 892
    frame #8: 0x00000001a6b7b864 libswiftCore.dylib`swift_getTypeByMangledNode + 836
    frame #9: 0x00000001a6b7c32c libswiftCore.dylib`swift_getTypeByMangledNameImpl(swift::MetadataRequest, __swift::__runtime::llvm::StringRef, void const* const*, std::__1::function<void const* (unsigned int, unsigned int)>, std::__1::function<swift::TargetWitnessTable<swift::InProcess> const* (swift::TargetMetadata<swift::InProcess> const*, unsigned int)>) + 1196
    frame #10: 0x00000001a6b75d70 libswiftCore.dylib`swift_getTypeByMangledName + 836
    frame #11: 0x00000001a6b9be28 libswiftCore.dylib`(anonymous namespace)::getFieldAt(swift::TargetMetadata<swift::InProcess> const*, unsigned int) + 556
    frame #12: 0x00000001a6b9d6b4 libswiftCore.dylib`decltype(fp2(nullptr)) (anonymous namespace)::call<swift_reflectionMirror_subscript::$_0>(swift::OpaqueValue*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift_reflectionMirror_subscript::$_0 const&)::'lambda'()::operator()() const + 352
    frame #13: 0x00000001a6b9a664 libswiftCore.dylib`swift_reflectionMirror_subscript + 456
    frame #14: 0x00000001a6b18984 libswiftCore.dylib`partial apply forwarder for closure #1 (Swift.Int) -> (label: Swift.Optional<Swift.String>, value: Any) in Swift.Mirror.init(internalReflecting: Any, subjectType: Swift.Optional<Any.Type>, customAncestor: Swift.Optional<Swift.Mirror>) -> Swift.Mirror + 72
    frame #15: 0x00000001a68f5ffc libswiftCore.dylib`Swift.LazyMapSequence< where τ_0_0: Swift.Collection>.subscript.read : (τ_0_0.Index) -> τ_0_1 + 388
    frame #16: 0x00000001a68f5e48 libswiftCore.dylib`protocol witness for Swift.Collection.subscript.read : (τ_0_0.Index) -> τ_0_0.Element in conformance < where τ_0_0: Swift.Collection> Swift.LazyMapSequence<τ_0_0, τ_0_1> : Swift.Collection in Swift + 72
    frame #17: 0x00000001a677cf44 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 656
    frame #18: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #19: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #20: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #21: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #22: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #23: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #24: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #25: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #26: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #27: 0x00000001a685ecd8 libswiftCore.dylib`Swift._CollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 308
    frame #28: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #29: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #30: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #31: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #32: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #33: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #34: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #35: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #36: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #37: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #38: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #39: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #40: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #41: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #42: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #43: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #44: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #45: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #46: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #47: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #48: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #49: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #50: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #51: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #52: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #53: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #54: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #55: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #56: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #57: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #58: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #59: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #60: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #61: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #62: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #63: 0x00000001a685ecd8 libswiftCore.dylib`Swift._CollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 308
    frame #64: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #65: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #66: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #67: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #68: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #69: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #70: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #71: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #72: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #73: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #74: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #75: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #76: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #77: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #78: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #79: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #80: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #81: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #82: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #83: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #84: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #85: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #86: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #87: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #88: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #89: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #90: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #91: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #92: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #93: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #94: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #95: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #96: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #97: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #98: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #99: 0x00000001a685ecd8 libswiftCore.dylib`Swift._CollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 308
    frame #100: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48


.....


    frame #3269: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #3270: 0x0000000103010214 Testing`closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 132
    frame #3271: 0x0000000103017e78 Testing`partial apply forwarder for closure #1 ((label: Swift.Optional<Swift.String>, value: Any)) -> Testing.__Expression.Value in Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 24
    frame #3272: 0x0000000103017e9c Testing`partial apply forwarder for generic specialization <(label: Swift.Optional<Swift.String>, value: Any), Testing.__Expression.Value, Swift.Never> of reabstraction thunk helper <τ_0_0><τ_1_0, τ_1_1 where τ_1_1: Swift.Error> from @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @out τ_1_1) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0) -> (@out τ_1_0, @error @owned Swift.Error) + 28
    frame #3273: 0x00000001a6adead8 libswiftCore.dylib`merged partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Collection> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 32
    frame #3274: 0x00000001a6ad870c libswiftCore.dylib`partial apply forwarder for reabstraction thunk helper <τ_0_0><τ_1_0 where τ_0_0: Swift.Sequence> from @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @owned Swift.Error) to @escaping @callee_guaranteed (@in_guaranteed τ_0_0.Swift.Sequence.Element) -> (@out τ_1_0, @error @out Swift.Error) + 16
    frame #3275: 0x00000001a677cf94 libswiftCore.dylib`merged generic partial specialization <Signature = @escaping @convention(thin) @convention(method) <τ_0_0><τ_1_0, τ_1_1 where τ_0_0: Swift.Collection, τ_1_1 == Swift.Error> (@guaranteed @callee_guaranteed @substituted <τ_0_0, τ_0_1, τ_0_2 where τ_0_0: ~Swift.Copyable, τ_0_0: ~Swift.Escapable, τ_0_1: ~Swift.Copyable, τ_0_1: ~Swift.Escapable, τ_0_2: ~Swift.Copyable, τ_0_2: ~Swift.Escapable> (@in_guaranteed τ_0_0) -> (@out τ_0_2, @error @out τ_0_1) for <τ_0_0.ElementSwift.Errorτ_1_0>, @in_guaranteed τ_0_0) -> (@owned Swift.Array<τ_1_0>, @error @owned Swift.Error)> of Swift.Collection.map<τ_0_0, τ_0_1 where τ_1_1: Swift.Error>((τ_0_0.Element) throws(τ_1_1) -> τ_1_0) throws(τ_1_1) -> Swift.Array<τ_1_0> + 736
    frame #3276: 0x00000001a6866658 libswiftCore.dylib`Swift._RandomAccessCollectionBox._map<τ_0_0>((τ_0_0.Element) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 316
    frame #3277: 0x00000001a6af7410 libswiftCore.dylib`dispatch thunk of Swift._AnySequenceBox._map<τ_0_0>((τ_0_0) throws -> τ_1_0) throws -> Swift.Array<τ_1_0> + 48
    frame #3278: 0x000000010300ff18 Testing`Testing.__Expression.Value.init(_reflecting: Any, label: Swift.Optional<Swift.String>, seenObjects: inout Swift.Dictionary<Swift.ObjectIdentifier, Swift.AnyObject>) -> Testing.__Expression.Value + 2324
    frame #3279: 0x0000000103010564 Testing`closure #1 (τ_0_0) -> Testing.__Expression.Value in Testing.__Expression.capturingRuntimeValue<τ_0_0>(Swift.Optional<τ_0_0>) -> Testing.__Expression + 152
    frame #3280: 0x0000000103017d90 Testing`partial apply forwarder for closure #1 (τ_0_0) -> Testing.__Expression.Value in Testing.__Expression.capturingRuntimeValue<τ_0_0>(Swift.Optional<τ_0_0>) -> Testing.__Expression + 24
    frame #3281: 0x000000010300c360 Testing`Swift.Optional.map<τ_0_0, τ_0_1 where τ_1_0: Swift.Error, τ_1_1: ~Swift.Copyable>((τ_0_0) throws(τ_1_0) -> τ_1_1) throws(τ_1_0) -> Swift.Optional<τ_1_1> + 516
    frame #3282: 0x000000010300d2cc Testing`Testing.__Expression.capturingRuntimeValue<τ_0_0>(Swift.Optional<τ_0_0>) -> Testing.__Expression + 456
    frame #3283: 0x000000010300da3c Testing`Testing.__Expression.capturingRuntimeValues<each τ_0_0, τ_0_1>(Swift.Optional<τ_0_1>, repeat Swift.Optional<τ_0_0>) -> Testing.__Expression + 1068
    frame #3284: 0x000000010300dbcc Testing`Testing.__Expression.capturingRuntimeValues<each τ_0_0, τ_0_1>(Swift.Optional<τ_0_1>, repeat Swift.Optional<τ_0_0>) -> Testing.__Expression + 1468
    frame #3285: 0x0000000102f9ca84 Testing`implicit closure #1 () -> Swift.Optional<Testing.__Expression> in Testing.__checkBinaryOperation<τ_0_0, τ_0_1>(_: τ_0_0, _: (τ_0_0, () -> τ_0_1) -> Swift.Bool, _: @autoclosure () -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) -> Swift.Result<(), Swift.Error> + 528
    frame #3286: 0x0000000102f9a55c Testing`Testing.__checkValue(_: Swift.Bool, expression: Testing.__Expression, expressionWithCapturedRuntimeValues: @autoclosure () -> Swift.Optional<Testing.__Expression>, mismatchedErrorDescription: @autoclosure () -> Swift.Optional<Swift.String>, difference: @autoclosure () -> Swift.Optional<Swift.String>, mismatchedExitConditionDescription: @autoclosure () -> Swift.Optional<Swift.String>, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) -> Swift.Result<(), Swift.Error> + 916
    frame #3287: 0x0000000102f9c828 Testing`Testing.__checkBinaryOperation<τ_0_0, τ_0_1>(_: τ_0_0, _: (τ_0_0, () -> τ_0_1) -> Swift.Bool, _: @autoclosure () -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) -> Swift.Result<(), Swift.Error> + 576
  * frame #3288: 0x0000000100dba64c SwiftExpectReproTests`testSimplestRepro() [inlined] freestanding macro expansion #1 of expect in module SwiftExpectReproTests file SwiftExpectReproTests.swift line 7 column 5 at @__swiftmacro_21SwiftExpectReproTests0032SwiftExpectReproTestsswift_jIADjfMX6_4_6expectfMf_.swift:1:1
    frame #3289: 0x0000000100dba43c SwiftExpectReproTests`testSimplestRepro() at SwiftExpectReproTests.swift:7:5
    frame #3290: 0x0000000100dba744 SwiftExpectReproTests`closure #2 in $s21SwiftExpectReproTests012testSimplestC04TestfMp_23functestSimplestRepro__fMu_@Sendable () at @__swiftmacro_21SwiftExpectReproTests012testSimplestC04TestfMp_.swift:6:20
    frame #3291: 0x00000001030484b4 Testing`(3) await resume partial function for Testing.__ifMainActorIsolationEnforced<τ_0_0 where τ_0_0: Swift.Sendable>(_: @Swift.MainActor @Sendable () async throws -> τ_0_0, else: @Sendable () async throws -> τ_0_0) async throws -> τ_0_0
    frame #3292: 0x0000000100db9e70 SwiftExpectReproTests`$s21SwiftExpectReproTests012testSimplestC04TestfMp_23functestSimplestRepro__fMu_@Sendable () at @__swiftmacro_21SwiftExpectReproTests012testSimplestC04TestfMp_.swift:3:13
    frame #3293: 0x0000000102fdafec Testing`(4) await resume partial function for closure #1 () async throws -> () in closure #1 () async -> () in Testing.Runner._runTestCase(_: Testing.Test.Case, within: Testing.Runner.Plan.Step) async throws -> ()
    frame #3294: 0x0000000102f66448 Testing`(1) await resume partial function for partial apply forwarder for closure #1 () -> sending τ_0_1 in Testing.__checkClosureCall<τ_0_0, τ_0_1 where τ_0_0: Swift.Equatable, τ_0_0: Swift.Error>(throws: τ_0_0, performing: () async throws -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) async -> Swift.Result<(), Swift.Error>
    frame #3295: 0x0000000102fb1b94 Testing`(2) await resume partial function for function signature specialization <Arg[4] = Dead> of static Testing.Issue.withErrorRecording(at: Testing.SourceLocation, configuration: Swift.Optional<Testing.Configuration>, isolation: isolated Swift.Optional<Swift.Actor>, _: () async throws -> ()) async -> Swift.Optional<Swift.Error>
    frame #3296: 0x0000000102fda504 Testing`(2) await resume partial function for closure #1 () async -> () in Testing.Runner._runTestCase(_: Testing.Test.Case, within: Testing.Runner.Plan.Step) async throws -> ()
    frame #3297: 0x0000000102f66448 Testing`(1) await resume partial function for partial apply forwarder for closure #1 () -> sending τ_0_1 in Testing.__checkClosureCall<τ_0_0, τ_0_1 where τ_0_0: Swift.Equatable, τ_0_0: Swift.Error>(throws: τ_0_0, performing: () async throws -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) async -> Swift.Result<(), Swift.Error>
    frame #3298: 0x0000000270693e18 libswift_Concurrency.dylib`(2) await resume partial function for Swift.TaskLocal.withValueImpl<τ_0_0>(_: __owned τ_0_0, operation: () async throws -> τ_1_0, isolation: isolated Swift.Optional<Swift.Actor>, file: Swift.String, line: Swift.UInt) async throws -> τ_1_0
    frame #3299: 0x0000000270693ab4 libswift_Concurrency.dylib`(2) await resume partial function for Swift.TaskLocal.withValue<τ_0_0>(_: τ_0_0, operation: () async throws -> τ_1_0, isolation: isolated Swift.Optional<Swift.Actor>, file: Swift.String, line: Swift.UInt) async throws -> τ_1_0
    frame #3300: 0x0000000102fdc5b4 Testing`(2) await resume partial function for generic specialization <()> of static Testing.Test.Case.withCurrent<τ_0_0>(_: Testing.Test.Case, perform: () async throws -> τ_0_0) async throws -> τ_0_0
    frame #3301: 0x0000000102fd9f74 Testing`(2) await resume partial function for Testing.Runner._runTestCase(_: Testing.Test.Case, within: Testing.Runner.Plan.Step) async throws -> ()
    frame #3302: 0x0000000102fd99f0 Testing`(1) await resume partial function for closure #2 @Sendable (Testing.Test.Case) async throws -> () in Testing.Runner._runTestCases<τ_0_0 where τ_0_0: Swift.Sequence, τ_0_0.Element == Testing.Test.Case>(_: τ_0_0, within: Testing.Runner.Plan.Step) async throws -> ()
    frame #3303: 0x0000000102f66448 Testing`(1) await resume partial function for partial apply forwarder for closure #1 () -> sending τ_0_1 in Testing.__checkClosureCall<τ_0_0, τ_0_1 where τ_0_0: Swift.Equatable, τ_0_0: Swift.Error>(throws: τ_0_0, performing: () async throws -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) async -> Swift.Result<(), Swift.Error>
    frame #3304: 0x0000000102fe5e0c Testing`(1) await resume partial function for generic not re-abstracted specialization <Testing.Test.Case, Swift.LazyFilterSequence<Swift.AnySequence<Testing.Test.Case>>> of closure #1 () async throws -> () in closure #1 (inout Swift.ThrowingTaskGroup<(), Swift.Error>) async throws -> () in Testing.Runner._forEach<τ_0_0, τ_0_1 where τ_0_0: Swift.Sendable, τ_0_0 == τ_0_1.Element, τ_0_1: Swift.Sequence>(in: τ_0_1, for: Swift.Optional<Testing.Runner.Plan.Step>, _: @Sendable (τ_0_0) async throws -> ()) async throws -> ()
    frame #3305: 0x0000000102f66448 Testing`(1) await resume partial function for partial apply forwarder for closure #1 () -> sending τ_0_1 in Testing.__checkClosureCall<τ_0_0, τ_0_1 where τ_0_0: Swift.Equatable, τ_0_0: Swift.Error>(throws: τ_0_0, performing: () async throws -> τ_0_1, expression: Testing.__Expression, comments: @autoclosure () -> Swift.Array<Testing.Comment>, isRequired: Swift.Bool, sourceLocation: Testing.SourceLocation) async -> Swift.Result<(), Swift.Error>

Expected behavior

I'd expect it to print the failed assertion, like it does if only two of the items have references to the parent.

Environment

swift-driver version: 1.115 Apple Swift version 6.0.2 (swiftlang-6.0.2.1.2 clang-1600.0.26.4)
Target: arm64-apple-macosx15.0

IPS Crash Report

Additional information

Possibly related:

• #expect crashes with EXC_BAD_ACCESS when condition comparing generics is false #76608
• EXC_BAD_ACCESS at XCTAssertEqual #70430
• App using Swift macros unexpectedly report EXC_BAD_ACCESS errors #70469

https://github.com/swiftlang/swift-testing/blob/57335d72b1ed5dda16db61c35dd4551976bda920/Sources/Testing/SourceAttribution/Expression.swift#L439

https://github.com/swiftlang/swift-testing/blob/57335d72b1ed5dda16db61c35dd4551976bda920/Sources/Testing/SourceAttribution/Expression.swift#L238