子类NSObject和使用泛型时的快速编译错误

Question

以下Swift代码在构建时生成编译错误：

import Foundation

class Wrapper<T> : NSObject {
    let obj : T

    init(x : T) {
        self.obj = x
    }
}

是我做错什么了还是这是编译器的错误？

如果是的话，我能做些什么来解决这个问题呢？

错误日志：

CompileSwift normal i386 com.apple.xcode.tools.swift.compiler
    cd /Users/hermespique/workspace/HanekeSwift
    export PATH="/Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode6-Beta.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -target i386-apple-ios8.0 -module-name HanekeTests -O0 -sdk /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk -g -module-cache-path /Users/hermespique/Library/Developer/Xcode/DerivedData/ModuleCache -I /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator -F /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk/Developer/Library/Frameworks -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Frameworks -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk/Developer/Library/Frameworks -c -j4 /Users/hermespique/workspace/HanekeSwift/HanekeTests/XCTestCase+Assert.swift /Users/hermespique/workspace/HanekeSwift/HanekeTests/Cache.swift /Users/hermespique/workspace/HanekeSwift/HanekeTests/Wrapper.swift -output-file-map /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/HanekeTests-OutputFileMap.json -serialize-diagnostics -emit-dependencies -emit-module -emit-module-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/HanekeTests.swiftmodule -Xcc -iquote -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-generated-files.hmap -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-own-target-headers.hmap -Xcc -ivfsoverlay -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/all-product-headers.yaml -Xcc -iquote -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-project-headers.hmap -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator/include -Xcc -I/Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/DerivedSources/i386 -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/DerivedSources -Xcc -DDEBUG=1 -Xcc -DDEBUG=1 -emit-objc-header -emit-objc-header-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/HanekeTests-Swift.h

0  swift                    0x000000010a889608 llvm::sys::PrintStackTrace(__sFILE*) + 40
1  swift                    0x000000010a889af4 SignalHandler(int) + 452
2  libsystem_platform.dylib 0x00007fff88e185aa _sigtramp + 26
3  libsystem_platform.dylib 0x00007fff55fb0334 _sigtramp + 3440999844
4  swift                    0x0000000109c87395 swift::irgen::IRGenFunction::emitTypeMetadataRef(swift::CanType) + 21
5  swift                    0x0000000109cbcfb8 (anonymous namespace)::OpaqueArchetypeTypeInfo::destroy(swift::irgen::IRGenFunction&, swift::irgen::Address, swift::CanType) const + 24
6  swift                    0x0000000109cf467b swift::SILVisitor<(anonymous namespace)::IRGenSILFunction, void>::visit(swift::ValueBase*) + 23579
7  swift                    0x0000000109cee266 swift::irgen::IRGenModule::emitSILFunction(swift::SILFunction*) + 8678
8  swift                    0x0000000109c6f6f8 swift::irgen::IRGenModule::emitGlobalTopLevel() + 184
9  swift                    0x0000000109cdb6e3 performIRGeneration(swift::IRGenOptions&, swift::Module*, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, swift::SourceFile*, unsigned int) + 1859
10 swift                    0x0000000109cdc033 swift::performIRGeneration(swift::IRGenOptions&, swift::SourceFile&, swift::SILModule*, llvm::StringRef, llvm::LLVMContext&, unsigned int) + 51
11 swift                    0x0000000109c4e65a frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 4842
12 swift                    0x0000000109c4d35d main + 1533
13 libdyld.dylib            0x00007fff8ddbb5fd start + 1
14 libdyld.dylib            0x0000000000000040 start + 1914980932
Stack dump:
0.  Program arguments: /Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift -frontend -c /Users/hermespique/workspace/HanekeSwift/HanekeTests/XCTestCase+Assert.swift /Users/hermespique/workspace/HanekeSwift/HanekeTests/Cache.swift -primary-file /Users/hermespique/workspace/HanekeSwift/HanekeTests/Wrapper.swift -enable-objc-attr-requires-objc-module -target i386-apple-ios8.0 -module-name HanekeTests -sdk /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk -I /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator -F /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk/Developer/Library/Frameworks -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Frameworks -F /Applications/Xcode6-Beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator8.0.sdk/Developer/Library/Frameworks -g -module-cache-path /Users/hermespique/Library/Developer/Xcode/DerivedData/ModuleCache -Xcc -iquote -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-generated-files.hmap -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-own-target-headers.hmap -Xcc -ivfsoverlay -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/all-product-headers.yaml -Xcc -iquote -Xcc /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/HanekeTests-project-headers.hmap -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Products/Debug-iphonesimulator/include -Xcc -I/Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/DerivedSources/i386 -Xcc -I/Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/DerivedSources -Xcc -DDEBUG=1 -Xcc -DDEBUG=1 -emit-module-doc-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/Wrapper~partial.swiftdoc -O0 -emit-module-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/Wrapper~partial.swiftmodule -serialize-diagnostics-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/Wrapper.dia -emit-dependencies-path /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/Wrapper.d -o /Users/hermespique/Library/Developer/Xcode/DerivedData/Haneke-dsgqpxenngbaqpctbkhhwtqbiorj/Build/Intermediates/Haneke.build/Debug-iphonesimulator/HanekeTests.build/Objects-normal/i386/Wrapper.o 
1.  While emitting IR SIL function @_TToFC11HanekeTests7WrapperE for 'deinit' at /Users/hermespique/workspace/HanekeSwift/HanekeTests/Wrapper.swift:11:7
<unknown>:0: error: unable to execute command: Segmentation fault: 11
<unknown>:0: error: swift frontend command failed due to signal (use -v to see invocation)
Command /Applications/Xcode6-Beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/swift failed with exit code 254

Answer 1

我找到了解决这个问题的办法

class Wrapper<T> {
    let _val: T[]

    init(_ v: T) {
        _val = [v]
    }

    var val : T {
        get {
            return _val[0]
        }
        set {
            _val[0] = newValue
        }
    }
}

因为Array是一个引用类型(即使它是struct)，所以Wrapper类的大小现在是固定的，编译器可以处理它。

Answer 2

我认为这是一个带有泛型和NSObject的X代码错误。

class Foo<T>:NSObject{
    let _foo:T?

    init(foo:T){
        _foo  = foo
    }
}

给出了退出代码254失败

删除NSObject可以正常工作。ie：

class Foo<T>{
    let _foo:T?

    init(foo:T){
        _foo  = foo
    }
}

或者向泛型添加约束似乎是有效的。ie：

class Foo<T:AnyObject>:NSObject{
    let _foo:T?

    init(foo:T){
        _foo  = foo
    }
}

Answer 3

我篡改了您感兴趣的(+1)代码片段，下面是我在避免编译器错误时能得到的最接近的代码：

struct Wrapper<T>  {
    var obj : T

    init(_ x : T) {
        obj = x
    }
}

所以，如果你真的不需要包装器才能成为一个类，那么你就可以继续.直到下一版本的Xcode ;)