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The Swift Programming Language
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[SR-10491] AST Verifier crash on IUO unwrap through AnyObject lookup #52891

Open hamishknight opened 5 years ago

hamishknight commented 5 years ago
Previous ID SR-10491
Radar rdar://problem/50169795
Original Reporter @hamishknight
Type Bug
Environment Swift version 5.0-dev (LLVM 94d957ca75, Swift 130cd9e81f) Target: x86_64-apple-darwin18.5.0
Additional Detail from JIRA | | | |------------------|-----------------| |Votes | 0 | |Component/s | Compiler | |Labels | Bug, CompilerCrash, TypeChecker | |Assignee | None | |Priority | Medium | md5: ce4521d5f7dccd1e87ea948b15e07401

Issue Description:

The following crashes the AST verifier:

import Foundation

class C {
  @objc func foo() -> String! { return nil }
}

func bar(_ x: AnyObject) {
  let y: String = x.foo!()
}

Stack dump:

0.  Program arguments: ./swift -frontend -typecheck /Users/hamishknight/Desktop/Stochastic Projects/hang on a gosh darn sec/hang on a gosh darn sec/main.swift -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk
1.  While walking into decl 'bar(_:)' (at /Users/hamishknight/Desktop/Stochastic Projects/hang on a gosh darn sec/hang on a gosh darn sec/main.swift:15:1)
2.  While walking into body of 'bar(_:)' (at /Users/hamishknight/Desktop/Stochastic Projects/hang on a gosh darn sec/hang on a gosh darn sec/main.swift:15:1)
3.  While walking into initializer for declaration 0x7fb5288cfb00 (at /Users/hamishknight/Desktop/Stochastic Projects/hang on a gosh darn sec/hang on a gosh darn sec/main.swift:16:3)
0  swift                    0x0000000112eaa585 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1  swift                    0x0000000112ea9588 llvm::sys::RunSignalHandlers() + 248
2  swift                    0x0000000112eaab88 SignalHandler(int) + 264
3  libsystem_platform.dylib 0x00007fff61b98b5d _sigtramp + 29
4  libsystem_platform.dylib 000000000000000000 _sigtramp + 2655417536
5  swift                    0x000000010fe3d789 (anonymous namespace)::Verifier::checkSameType(swift::Type, swift::Type, char const*) + 41
6  swift                    0x000000010fe3f0e1 (anonymous namespace)::Verifier::checkOptionalObjectType(swift::Type, swift::Type, swift::Expr*) + 81
7  swift                    0x000000010fe332f8 (anonymous namespace)::Verifier::walkToExprPost(swift::Expr*) + 13656
8  swift                    0x000000010fe4657b (anonymous namespace)::Traversal::visitApplyExpr(swift::ApplyExpr*) + 123
9  swift                    0x000000010fe487c0 swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Decl*) + 752
10 swift                    0x000000010fe43af7 (anonymous namespace)::Traversal::doIt(swift::Decl*) + 215
11 swift                    0x000000010fe468c8 swift::ASTVisitor<(anonymous namespace)::Traversal, swift::Expr*, swift::Stmt*, bool, swift::Pattern*, bool, void>::visit(swift::Stmt*) + 472
12 swift                    0x000000010fe4983e (anonymous namespace)::Traversal::visitAbstractFunctionDecl(swift::AbstractFunctionDecl*) + 782
13 swift                    0x000000010fe43af7 (anonymous namespace)::Traversal::doIt(swift::Decl*) + 215
14 swift                    0x000000010fe43a0b swift::Decl::walk(swift::ASTWalker&) + 27
15 swift                    0x000000010fef9f1a swift::SourceFile::walk(swift::ASTWalker&) + 170
16 swift                    0x000000010fe2ef4b swift::verify(swift::SourceFile&) + 59
17 swift                    0x000000010fbe6425 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int) + 1381
18 swift                    0x000000010f3708f6 swift::CompilerInstance::parseAndTypeCheckMainFileUpTo(swift::SourceFile::ASTStage_t, swift::PersistentParserState&, swift::DelayedParsingCallbacks*, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>) + 502
19 swift                    0x000000010f36f403 swift::CompilerInstance::parseAndCheckTypesUpTo(swift::CompilerInstance::ImplicitImports const&, swift::SourceFile::ASTStage_t) + 339
20 swift                    0x000000010f36ebf7 swift::CompilerInstance::performSemaUpTo(swift::SourceFile::ASTStage_t) + 615
21 swift                    0x000000010f13c2dd performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 1613
22 swift                    0x000000010f13ac36 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2982
23 swift                    0x000000010f0e1b08 main + 696
24 libdyld.dylib            0x00007fff619b33d5 start + 1
fish: './swift -frontend -typecheck /U…' terminated by signal SIGSEGV (Address boundary error)
hamishknight commented 5 years ago

Here's hoping we can deprecate AnyObject lookup soon