将现有项目迁移到 Xcode 10 GM 种子时出现分段错误 11

Question

新的 Xcode GM 种子（以及之前的 beta 6）无法构建，存在多个分段错误 11 个错误（使用 swift 4.2）。即使我删除、重命名或注释掉有问题的 class(es)，错误也不会消失。

项目在 Swift 4.1 和 Xcode 9.

上构建没有问题

出现错误的示例class：

import Foundation

/// Possible sides for a corner.
public enum CornerSide {
    /// Corner on the left side.
    case left,
    /// Corner on the right side.
    right
}

或

import Foundation

extension Int {
    var toString: String { return "\(self)" }
}

或

import Foundation

public class DemoStatistics: Statistics { }

统计数据 class 是一个普通的 class，具有功能和扩展（没什么特别的）。

堆栈跟踪：

0  swift                    0x000000011199264a PrintStackTraceSignalHandler(void*) + 42
1  swift                    0x0000000111991dfe SignalHandler(int) + 302
2  libsystem_platform.dylib 0x00007fff7e337f5a _sigtramp + 26
3  libsystem_platform.dylib 0x00007fd691b0bcd8 _sigtramp + 326974872
4  swift                    0x000000010f17e126 swift::ProtocolConformanceRef::subst(swift::Type, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>) const + 550
5  swift                    0x000000010f18a7f9 swift::SubstitutionMap::subst(llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>) const + 761
6  swift                    0x000000010f17e4fd swift::ProtocolConformance::subst(swift::Type, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>) const + 749
7  swift                    0x000000010f17e7bb swift::ProtocolConformance::subst(swift::Type, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>) const + 1451
8  swift                    0x000000010eda6e59 swift::ConformanceChecker::ensureRequirementsAreSatisfied(bool)::GatherConformancesListener::satisfiedConformance(swift::Type, swift::Type, swift::ProtocolConformanceRef) + 201
9  swift                    0x000000010ed7cc2f swift::TypeChecker::checkGenericArguments(swift::DeclContext*, swift::SourceLoc, swift::SourceLoc, swift::Type, swift::ArrayRefView<swift::Type, swift::GenericTypeParamType*, swift::GenericTypeParamType* swift::staticCastHelper<swift::GenericTypeParamType>(swift::Type const&), true>, llvm::ArrayRef<swift::Requirement>, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>, llvm::function_ref<bool (swift::TypeCheckRequest)>*, swift::OptionSet<swift::ConformanceCheckFlags, unsigned int>, swift::GenericRequirementsCheckListener*, swift::SubstOptions) + 1103
10 swift                    0x000000010eda6bcd swift::ConformanceChecker::ensureRequirementsAreSatisfied(bool) + 1325
11 swift                    0x000000010edc24ba swift::ConformanceChecker::resolveTypeWitnesses() + 378
12 swift                    0x000000010ed92973 swift::MultiConformanceChecker::checkIndividualConformance(swift::NormalProtocolConformance*, bool) + 11347
13 swift                    0x000000010ed8f8c2 swift::MultiConformanceChecker::checkAllConformances() + 162
14 swift                    0x000000010eda8ac7 swift::TypeChecker::checkConformancesInContext(swift::DeclContext*, swift::IterableDeclContext*) + 4279
15 swift                    0x000000010edf2f94 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int) + 2388
16 swift                    0x000000010ea2d865 swift::CompilerInstance::performSema() + 4949
17 swift                    0x000000010dc1a59b performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 731
18 swift                    0x000000010dc16dc5 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 7717
19 swift                    0x000000010dbbca35 main + 1349
20 libdyld.dylib            0x00007fff7e029015 start + 1
21 libdyld.dylib            0x00000000000000ac start + 2180870296

出现错误的所有 class 都在我正在构建并在示例 iOS 应用程序中使用的框架中。任何帮助将不胜感激。

Answer 1

自己设法解决了这个问题。问题出在单个通用 class 上，它从同一协议继承了两次（一次是直接继承的，一次是通过另一个协议继承的）。

奇怪的是，swift 4.1 和 Xcode 9 没问题，而且 Segmentation fault 11 位置与实际错误所在位置无关。

将现有项目迁移到 Xcode 10 GM 种子时出现分段错误 11

Segmentation fault 11 when migrating existing project to Xcode 10 GM seed

ios

swift

xcode10

swift4.2