[SR-13365] Segmentation fault: 11

[swift-ci]

Previous ID	SR-13365
Radar	rdar://problem/67361238
Original Reporter	linqingmo (JIRA User)
Type	Bug

Environment

Xcode 11.6

Additional Detail from JIRA

| | | |------------------|-----------------| |Votes | 0 | |Component/s | Compiler | |Labels | Bug, CompilerCrash | |Assignee | None | |Priority | Medium | md5: f1f7a384ca8e96740fe4ebe78da284eb

Issue Description:

extension Result: Decodable where Success: Decodable, Failure: Decodable {
    public init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        do {
            let success = try container.decode(Success.self)
            self = .success(success)
        } catch {
            let failure = try container.decode(Failure.self)
            self = .failure(failure)
        }
    }
}

struct Failure: Error, Decodable {
    let message: String
}

class Test<V: Decodable> {}

class Test2<V: Decodable>: Test<Result<V, Failure>> { // Error
}

protocol CustomDecodable: Decodable {
    init(fromCustom decoder: Decoder) throws
}

extension Result: CustomDecodable where Success: Decodable, Failure: Decodable {
    public init(fromCustom decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        do {
            let success = try container.decode(Success.self)
            self = .success(success)
        } catch {
            let failure = try container.decode(Failure.self)
            self = .failure(failure)
        }
    }
}

class TestC<V: CustomDecodable> {}

class Test3<V: CustomDecodable>: TestC<Result<V, Failure>> { // OK
}

error:

1.  Apple Swift version 5.2.4 (swiftlang-1103.0.32.9 clang-1103.0.32.53)
2.  While emitting IR for source file /Users/linqingmo/lolipop/TestDecodable/TestDecodable/main.swift
3.  While emitting class metadata for 'Test2' (at /Users/linqingmo/lolipop/TestDecodable/TestDecodable/main.swift:32:1)
4.  While emitting metadata for 'Test2' (at /Users/linqingmo/lolipop/TestDecodable/TestDecodable/main.swift:32:1)
0  swift                    0x000000010f0e64ea PrintStackTraceSignalHandler(void*) + 42
1  swift                    0x000000010f0e5cc0 SignalHandler(int) + 352
2  libsystem_platform.dylib 0x00007fff6bfd45fd _sigtramp + 29
3  swift                    0x000000010bf42650 llvm::Optional<swift::Type> llvm::function_ref<llvm::Optional<swift::Type> (swift::TypeBase*)>::callback_fn<substType(swift::Type, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<swift::ProtocolConformanceRef (swift::CanType, swift::Type, swift::ProtocolDecl*)>, swift::SubstOptions)::$_23>(long, swift::TypeBase*) + 0
4  swift                    0x000000010bebf1ef swift::GenericSignatureImpl::getConformanceAccessPath(swift::Type, swift::ProtocolDecl*) + 31
5  swift                    0x000000010bdd8a65 swift::Mangle::ASTMangler::appendConcreteProtocolConformance(swift::ProtocolConformance const*) + 1925
6  swift                    0x000000010bdd5e17 swift::Mangle::ASTMangler::appendRetroactiveConformances(swift::SubstitutionMap, swift::ModuleDecl*) + 199
7  swift                    0x000000010bdd3ec6 swift::Mangle::ASTMangler::appendType(swift::Type, swift::ValueDecl const*) + 8774
8  swift                    0x000000010b05fcbf swift::irgen::IRGenMangler::mangleTypeForReflection(swift::irgen::IRGenModule&, swift::Type) + 255
9  swift                    0x000000010b003cd6 getTypeRefImpl(swift::irgen::IRGenModule&, swift::CanType, swift::CanGenericSignature, swift::irgen::MangledTypeRefRole) + 1430
10 swift                    0x000000010afb9fc4 (anonymous namespace)::TypeContextDescriptorBuilderBase<(anonymous namespace)::ClassContextDescriptorBuilder, swift::ClassDecl>::emit() + 3172
11 swift                    0x000000010afd5186 swift::irgen::emitClassMetadata(swift::irgen::IRGenModule&, swift::ClassDecl*, swift::irgen::ClassLayout const&, swift::irgen::ClassLayout const&) + 22246
12 swift                    0x000000010af01aaa swift::irgen::IRGenModule::emitClassDecl(swift::ClassDecl*) + 346
13 swift                    0x000000010af1177b swift::irgen::IRGenModule::emitSourceFile(swift::SourceFile&) + 123
14 swift                    0x000000010b04b65e performIRGeneration(swift::IRGenOptions&, swift::ModuleDecl*, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, llvm::StringRef, swift::PrimarySpecificPaths const&, llvm::LLVMContext&, swift::SourceFile*, llvm::GlobalVariable**) + 1118
15 swift                    0x000000010ae42a5f performCompileStepsPostSILGen(swift::CompilerInstance&, swift::CompilerInvocation&, std::__1::unique_ptr<swift::SILModule, std::__1::default_delete<swift::SILModule> >, bool, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, bool, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 4255
16 swift                    0x000000010ae37eba swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 48426
17 swift                    0x000000010adafb73 main + 1283
18 libdyld.dylib            0x00007fff6bddbcc9 start + 1
19 libdyld.dylib            0x000000000000004a start + 2485273474
error: Segmentation fault: 11

[theblixguy]

You seem to have created a TensorFlow bug report, rather than a Swift bug report. Anyway, here's a simplified reproducer:

extension Result: Decodable where Success: Decodable, Failure: Decodable {
  public init(from decoder: Decoder) throws {
    fatalError()
  }
}

struct Failure: Error, Decodable {}

class Base<T: Decodable> {}
class Derived<T: Decodable>: Base<Result<T, Failure>> {}

[typesanitizer]

@swift-ci create