[SR-4210] Segmentation Fault: 11 Using Protocol w/ associatedType w/ Class Constraint

[swift-ci]

Previous ID	SR-4210
Radar	rdar://problem/30976603
Original Reporter	michael (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Attachment: Download

Environment

Version 8.3 beta 4 (8W143q)
Toolchain: Swift Development Snapshot 2017-03-08 (a)

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 3.1Regression, CompilerCrash
Assignee	None
Priority	Medium

md5: 1871cd607a6c6bb829baefe94aba24ab

Issue Description:

Using the latest Swift 3.1 Snapshot at the time of this writing (2017-03-08 (a)) and Xcode 8.3 beta 4, a "Segmentation Fault: 11" error occurs with the following code.

/// A simple `class` type used to constrain the collection’s element type. Any existing class will do, e.g. `NSError`.
class Object { }

/// A protocol for `Object` collection types.
protocol ObjectCollectionProtocol {
    associatedtype Element: Object
}

/// A concrete implementation of `ObjectCollectionProtocol`.
final class ObjectCollection<T: Object>: ObjectCollectionProtocol {
    typealias Element = T
    
    /// This initializer’s signature creates a "Segmentation fault: 11" error.
    init<C: ObjectCollectionProtocol>(_ baseCollection: C) where C.Element == T { }
}

This does not occur in some earlier snapshots, or earlier versions of Swift. Note that this is a very isolated example of the same error I experience trying to build Realm, specifically at the initializer here.

The error details from the snippet above in the "SegFault11" project in SegFault11.swift (attached):

CompileSwift normal x86_64 /Users/Michael/Desktop/SegFault11/SegFault11/SegFault11.swift
    cd /Users/Michael/Desktop/SegFault11
    /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2017-03-08-a.xctoolchain/usr/bin/swift -frontend -c -primary-file /Users/Michael/Desktop/SegFault11/SegFault11/SegFault11.swift /Users/Michael/Desktop/SegFault11/SegFault11/ViewController.swift /Users/Michael/Desktop/SegFault11/SegFault11/AppDelegate.swift -target x86_64-apple-ios10.3 -enable-objc-interop -sdk "/Users/Michael/Downloads/Xcode-beta 2.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator10.3.sdk" -I /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator -F /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator -enable-testing -g -module-cache-path /Users/Michael/Library/Developer/Xcode/DerivedData/ModuleCache -D DEBUG -serialize-debugging-options -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/swift-overrides.hmap -Xcc -iquote -Xcc /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-generated-files.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-own-target-headers.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-all-target-headers.hmap -Xcc -iquote -Xcc /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-project-headers.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator/include -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/DerivedSources/x86_64 -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/DerivedSources -Xcc -DDEBUG=1 -Xcc -working-directory/Users/Michael/Desktop/SegFault11 -emit-module-doc-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11~partial.swiftdoc -serialize-diagnostics-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.dia -Onone -module-name SegFault11 -emit-module-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11~partial.swiftmodule -emit-dependencies-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.d -emit-reference-dependencies-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.swiftdeps -o /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.o

0  swift                    0x0000000111f85898 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 40
1  swift                    0x0000000111f84ab6 llvm::sys::RunSignalHandlers() + 86
2  swift                    0x0000000111f85ee9 SignalHandler(int) + 361
3  libsystem_platform.dylib 0x00007fffa26fbbba _sigtramp + 26
4  libsystem_platform.dylib 0x00007fa4541d1590 _sigtramp + 2980927984
5  swift                    0x000000010fdc132c swift::GenericSignatureBuilder::addSameTypeRequirementBetweenArchetypes(swift::GenericSignatureBuilder::PotentialArchetype*, swift::GenericSignatureBuilder::PotentialArchetype*, swift::GenericSignatureBuilder::RequirementSource const*) + 1612
6  swift                    0x000000010fdbbef6 swift::GenericSignatureBuilder::addSameTypeRequirement(swift::GenericSignatureBuilder::ResolvedType, swift::GenericSignatureBuilder::ResolvedType, swift::GenericSignatureBuilder::FloatingRequirementSource, llvm::function_ref<void (swift::Type, swift::Type)>) + 102
7  swift                    0x000000010fdbf91c swift::GenericSignatureBuilder::addRequirement(swift::Requirement const&, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::SubstitutionMap const*, llvm::SmallPtrSetImpl<swift::ProtocolDecl*>&) + 924
8  swift                    0x000000010fdbfd92 swift::GenericSignatureBuilder::addRequirement(swift::RequirementRepr const*, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::SubstitutionMap const*) + 834
9  swift                    0x000000010fdc224a swift::GenericSignatureBuilder::addRequirement(swift::RequirementRepr const*) + 90
10 swift                    0x000000010fc8ab3b swift::TypeChecker::checkGenericParamList(swift::GenericSignatureBuilder*, swift::GenericParamList*, swift::GenericSignature*, swift::GenericTypeResolver*) + 459
11 swift                    0x000000010fc8b99b checkGenericFuncSignature(swift::TypeChecker&, swift::GenericSignatureBuilder*, swift::AbstractFunctionDecl*, swift::GenericTypeResolver&) + 107
12 swift                    0x000000010fc8b5f1 swift::TypeChecker::validateGenericFuncSignature(swift::AbstractFunctionDecl*) + 513
13 swift                    0x000000010fc713f9 (anonymous namespace)::DeclChecker::visitConstructorDecl(swift::ConstructorDecl*) + 1097
14 swift                    0x000000010fc614eb (anonymous namespace)::DeclChecker::visit(swift::Decl*) + 251
15 swift                    0x000000010fc6f83b (anonymous namespace)::DeclChecker::visitClassDecl(swift::ClassDecl*) + 315
16 swift                    0x000000010fc614db (anonymous namespace)::DeclChecker::visit(swift::Decl*) + 235
17 swift                    0x000000010fc613e4 swift::TypeChecker::typeCheckDecl(swift::Decl*, bool) + 100
18 swift                    0x000000010fcdbf84 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int) + 1524
19 swift                    0x000000010f8db089 swift::CompilerInstance::performSema() + 3897
20 swift                    0x000000010ee9451c swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 4380
21 swift                    0x000000010ee51e00 main + 3312
22 libdyld.dylib            0x00007fffa24ee255 start + 1
23 libdyld.dylib            0x000000000000003e start + 1571888618
Stack dump:
0.  Program arguments: /Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2017-03-08-a.xctoolchain/usr/bin/swift -frontend -c -primary-file /Users/Michael/Desktop/SegFault11/SegFault11/SegFault11.swift /Users/Michael/Desktop/SegFault11/SegFault11/ViewController.swift /Users/Michael/Desktop/SegFault11/SegFault11/AppDelegate.swift -target x86_64-apple-ios10.3 -enable-objc-interop -sdk /Users/Michael/Downloads/Xcode-beta 2.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator10.3.sdk -I /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator -F /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator -enable-testing -g -module-cache-path /Users/Michael/Library/Developer/Xcode/DerivedData/ModuleCache -D DEBUG -serialize-debugging-options -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/swift-overrides.hmap -Xcc -iquote -Xcc /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-generated-files.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-own-target-headers.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-all-target-headers.hmap -Xcc -iquote -Xcc /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/SegFault11-project-headers.hmap -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Products/Debug-iphonesimulator/include -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/DerivedSources/x86_64 -Xcc -I/Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/DerivedSources -Xcc -DDEBUG=1 -Xcc -working-directory/Users/Michael/Desktop/SegFault11 -emit-module-doc-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11~partial.swiftdoc -serialize-diagnostics-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.dia -Onone -module-name SegFault11 -emit-module-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11~partial.swiftmodule -emit-dependencies-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.d -emit-reference-dependencies-path /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.swiftdeps -o /Users/Michael/Library/Developer/Xcode/DerivedData/SegFault11-hkkupaxdvvekoialydwpgjtxyxyr/Build/Intermediates/SegFault11.build/Debug-iphonesimulator/SegFault11.build/Objects-normal/x86_64/SegFault11.o 
1.  While type-checking 'ObjectCollection' at /Users/Michael/Desktop/SegFault11/SegFault11/SegFault11.swift:18:7
2.  While type-checking 'init' at /Users/Michael/Desktop/SegFault11/SegFault11/SegFault11.swift:22:5

[belkadan]

Yikes. @slavapestov, @DougGregor, this is an area you've been actively working on.

[belkadan]

@swift-ci create

[DougGregor]

`GenericSignatureBuilder` is in the backtrace, so this crash is on master.

[DougGregor]

Hah, I ran across and fixed this issue last night.

[DougGregor]

7809118

[belkadan]

The originator says it's also failing in the 3.1 branch.

[DougGregor]

The example project builds with Xcode 8.3 beta 4, I broke this recently on master, and the stack trace is showing a type (`GenericSignatureBuilder`) that didn't exist on the 3.1 branch.

I'll check the latest 3.1 snapshot to see if there's something fishy there.

[DougGregor]

The 3.1 snapshot from March 8th builds cleanly, too. I think the submitter grabbed the snapshot from master, which had this bug (and which I subsequently fixed).