[swift-users] Assertion Failure When Using the swift-DEVELOPMENT-SNAPSHOT-2016-08-04-a Xcode Toolchain

[Saagar Jha]

Hello Swift Users,

This afternoon I updated my Xcode to Xcode 8 beta 4, and tried to compile one of my previously migrated Swift 3 projects. Along with a couple of renames, the compiler kept crashing due to a segmentation fault. Since the issue appeared to be similar to SR-2227, which was supposedly fixed with a pull request a couple days ago, I downloaded today’s snapshot toolchain. The new toolchain throws an assertion:

Assertion failed: (value != OpenExistentials.end() && "didn't see this OVE in a containing OpenExistentialExpr?"), function walkToExprPre, file /Users/buildnode/jenkins/workspace/oss-swift-package-osx/swift/lib/Sema/CSDiag.cpp, line 3082.
0  swift                    0x000000010a932ebb llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 43
1  swift                    0x000000010a932106 llvm::sys::RunSignalHandlers() + 70
2  swift                    0x000000010a93360f SignalHandler(int) + 383
3  libsystem_platform.dylib 0x00007fffa6122d7a _sigtramp + 26
4  libsystem_platform.dylib 0x0000000100000001 _sigtramp + 1508758177
5  swift                    0x000000010a93335e abort + 14
6  swift                    0x000000010a933341 __assert_rtn + 81
7  swift                    0x0000000108431879 eraseOpenedExistentials(swift::Expr*&)::ExistentialEraser::walkToExprPre(swift::Expr*) + 361
8  swift                    0x00000001085b8ea5 (anonymous namespace)::Traversal::visit(swift::Expr*) + 4981
9  swift                    0x00000001085b6f75 swift::Expr::walk(swift::ASTWalker&) + 53
10 swift                    0x000000010842e375 (anonymous namespace)::FailureDiagnosis::typeCheckChildIndependently(swift::Expr*, swift::Type, swift::ContextualTypePurpose, swift::OptionSet<TCCFlags, unsigned int>, swift::ExprTypeCheckListener*) + 1221
11 swift                    0x0000000108434ea3 (anonymous namespace)::FailureDiagnosis::typeCheckArgumentChildIndependently(swift::Expr*, swift::Type, (anonymous namespace)::CalleeCandidateInfo const&, swift::OptionSet<TCCFlags, unsigned int>) + 1987
12 swift                    0x000000010843e9a1 (anonymous namespace)::FailureDiagnosis::visitApplyExpr(swift::ApplyExpr*) + 913
13 swift                    0x0000000108428f6a swift::ASTVisitor<(anonymous namespace)::FailureDiagnosis, bool, void, void, void, void, void>::visit(swift::Expr*) + 170
14 swift                    0x0000000108422888 swift::constraints::ConstraintSystem::diagnoseFailureForExpr(swift::Expr*) + 104
15 swift                    0x00000001084289a8 swift::constraints::ConstraintSystem::salvage(llvm::SmallVectorImpl<swift::constraints::Solution>&, swift::Expr*) + 4056
16 swift                    0x00000001084ab665 swift::TypeChecker::solveForExpression(swift::Expr*&, swift::DeclContext*, swift::Type, swift::FreeTypeVariableBinding, swift::ExprTypeCheckListener*, swift::constraints::ConstraintSystem&, llvm::SmallVectorImpl<swift::constraints::Solution>&, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>) + 917
17 swift                    0x00000001084b17d1 swift::TypeChecker::typeCheckExpression(swift::Expr*&, swift::DeclContext*, swift::TypeLoc, swift::ContextualTypePurpose, swift::OptionSet<swift::TypeCheckExprFlags, unsigned int>, swift::ExprTypeCheckListener*, swift::constraints::ConstraintSystem*) + 625
18 swift                    0x000000010852c061 swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 545
19 swift                    0x000000010852c543 swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 1795
20 swift                    0x000000010852bf8e swift::ASTVisitor<(anonymous namespace)::StmtChecker, void, swift::Stmt*, void, void, void, void>::visit(swift::Stmt*) + 334
21 swift                    0x000000010852b369 (anonymous namespace)::StmtChecker::typeCheckBody(swift::BraceStmt*&) + 25
22 swift                    0x000000010852a63f swift::TypeChecker::typeCheckFunctionBodyUntil(swift::FuncDecl*, swift::SourceLoc) + 383
23 swift                    0x000000010852a463 swift::TypeChecker::typeCheckAbstractFunctionBodyUntil(swift::AbstractFunctionDecl*, swift::SourceLoc) + 35
24 swift                    0x000000010852afe4 swift::TypeChecker::typeCheckAbstractFunctionBody(swift::AbstractFunctionDecl*) + 180
25 swift                    0x00000001084e5c56 typeCheckFunctionsAndExternalDecls(swift::TypeChecker&) + 166
26 swift                    0x00000001084e68f0 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int) + 1568
27 swift                    0x000000010818798c swift::CompilerInstance::performSema() + 3916
28 swift                    0x0000000107c82ad1 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*) + 449
29 swift                    0x0000000107c8163f swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2895
30 swift                    0x0000000107c43ea0 main + 2448
31 libdyld.dylib            0x00007fffa5f16255 start + 1

The stack trace doesn’t really help tell me what’s going wrong; does anyone have the same issue or know why this is happening?

Thanks,
Saagar Jha

P.S. Should I file a bug on the JIRA?



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