[SR-4786] Infinite recursion in compareDependentTypes/getArchetypeAnchor with associated types with incompatible bounds

[huonw]

Previous ID	SR-4786
Radar	rdar://problem/31955862
Original Reporter	@huonw
Type	Bug
Status	Resolved
Resolution	Done

Environment

aa8d64c (2017-04-30)

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug
Assignee	None
Priority	Medium

md5: 39a4d5ccea1ff674919d7babbb66b65b

Issue Description:

public protocol _UTFEncoding {
    associatedtype EncodedScalar where EncodedScalar == Int
}

public protocol UnicodeEncoding {
    associatedtype EncodedScalar: BidirectionalCollection
}

public protocol _UTFParser {
    associatedtype Encoding: UnicodeEncoding, _UTFEncoding
}

  * frame #​0: 0x0000000100febda5 swift`compareDependentTypes(pa=0x00007fff5fbec598, pb=0x00007fff5fbec5a0) at GenericSignatureBuilder.cpp:1415 [opt]
    frame #&#8203;1: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;2: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;3: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;4: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;5: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;6: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;7: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;8: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;9: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;10: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]

...

    frame #&#8203;398: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;399: 0x0000000100fec09e swift`compareDependentTypes(pa=<unavailable>, pb=<unavailable>) at GenericSignatureBuilder.cpp:1438 [opt]
    frame #&#8203;400: 0x0000000100feb4e7 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=<unavailable>, builder=<unavailable>) at GenericSignatureBuilder.cpp:1511 [opt]
    frame #&#8203;401: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x000000010591f260, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;402: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x000000010591f520, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]

...

    frame #&#8203;598: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x0000000105a239d0, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;599: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x0000000105a23c90, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;600: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x0000000105a23f50, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;601: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x0000000105a24210, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;602: 0x0000000100feb235 swift`swift::GenericSignatureBuilder::PotentialArchetype::getArchetypeAnchor(this=0x0000000105a244d0, builder=0x00007fff5fbfc290) at GenericSignatureBuilder.cpp:1490 [opt]
    frame #&#8203;603: 0x0000000100ff78ea swift`swift::GenericSignatureBuilder::finalize(swift::SourceLoc, llvm::ArrayRef<swift::GenericTypeParamType*>, bool) at GenericSignatureBuilder.cpp:4858 [opt]
    frame #&#8203;604: 0x0000000100ff74c0 swift`swift::GenericSignatureBuilder::finalize(this=<unavailable>, loc=<unavailable>, genericParams=<unavailable>, allowConcreteGenericParams=<unavailable>) at GenericSignatureBuilder.cpp:3864 [opt]
    frame #&#8203;605: 0x0000000100ea71fd swift`swift::TypeChecker::checkGenericEnvironment(this=0x00007fff5fbfc8d8, genericParams=0x000000010739e0c8, dc=0x00000001074472a0, parentSig=<unavailable>, allowConcreteGenericParams=<unavailable>, inferRequirements=function_ref<void (swift::GenericSignatureBuilder &)> @ 0x00007fff5fbfc360)>) at TypeCheckGeneric.cpp:1168 [opt]
    frame #&#8203;606: 0x0000000100ea7622 swift`swift::TypeChecker::validateGenericTypeSignature(swift::GenericTypeDecl*) [inlined] swift::TypeChecker::checkGenericEnvironment(this=0x00007fff5fbfc8d8, genericParams=<unavailable>, outerSignature=<unavailable>, allowConcreteGenericParams=false) at TypeChecker.h:1316 [opt]
    frame #&#8203;607: 0x0000000100ea75ea swift`swift::TypeChecker::validateGenericTypeSignature(this=0x00007fff5fbfc8d8, typeDecl=<unavailable>) at TypeCheckGeneric.cpp:1234 [opt]
    frame #&#8203;608: 0x0000000100e7c5d2 swift`swift::TypeChecker::validateDecl(this=0x00007fff5fbfc8d8, D=0x0000000107449dd0) at TypeCheckDecl.cpp:7150 [opt]
    frame #&#8203;609: 0x0000000100e8aee6 swift`(anonymous namespace)::DeclChecker::visitProtocolDecl(this=0x00007fff5fbfc878, PD=0x0000000107449dd0) at TypeCheckDecl.cpp:4577 [opt]
    frame #&#8203;610: 0x0000000100e7ab57 swift`(anonymous namespace)::DeclChecker::visit(swift::Decl*) [inlined] swift::ASTVisitor<(anonymous namespace)::DeclChecker, void, void, void, void, void, void>::visit(D=0x0000000107449dd0) at DeclNodes.def:115 [opt]
    frame #&#8203;611: 0x0000000100e7a9cd swift`(anonymous namespace)::DeclChecker::visit(this=0x00007fff5fbfc878, decl=0x0000000107449dd0) at TypeCheckDecl.cpp:3813 [opt]
    frame #&#8203;612: 0x0000000100e7a974 swift`swift::TypeChecker::typeCheckDecl(this=0x00007fff5fbfc8d8, D=0x0000000107449dd0, isFirstPass=true) at TypeCheckDecl.cpp:6935 [opt]
    frame #&#8203;613: 0x0000000100efbc84 swift`swift::performTypeChecking(SF=<unavailable>, TLC=0x00007fff5fbfceb8, Options=<unavailable>, StartElem=<unavailable>, WarnLongFunctionBodies=<unavailable>) at TypeChecker.cpp:700 [opt]
    frame #&#8203;614: 0x0000000100a6b3ff swift`swift::CompilerInstance::performSema(this=<unavailable>) at Frontend.cpp:520 [opt]
    frame #&#8203;615: 0x0000000100043c8c swift`performCompile(Instance=0x00007fff5fbfe630, Invocation=0x00007fff5fbfd768, Args=<unavailable>, ReturnValue=0x00007fff5fbfe5f4, observer=0x0000000000000000, Stats=0x00007fff5fbfdd60) at FrontendTool.cpp:499 [opt]
    frame #&#8203;616: 0x000000010004282d swift`swift::performFrontend(Args=<unavailable>, Argv0=<unavailable>, MainAddr=<unavailable>, observer=0x0000000000000000) at FrontendTool.cpp:1193 [opt]
    frame #&#8203;617: 0x0000000100004676 swift`main(argc_=<unavailable>, argv_=<unavailable>) at driver.cpp:160 [opt]
    frame #&#8203;618: 0x00007fffeb2fc235 libdyld.dylib`start + 1
    frame #&#8203;619: 0x00007fffeb2fc235 libdyld.dylib`start + 1

[huonw]

@swift-ci create

[DougGregor]

89bed63