[swiftc (31 vs. 5565)] Add crasher in swift::GenericSignatureBuilder::addRequirement

Add test case for crash triggered in `swift::GenericSignatureBuilder::addRequirement`.

Current number of unresolved compiler crashers: 31 (5565 resolved)

Stack trace:

```
0 0x0000000003a7b018 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/path/to/swift/bin/swift+0x3a7b018)
1 0x0000000003a7b756 SignalHandler(int) (/path/to/swift/bin/swift+0x3a7b756)
2 0x00007ff6250c5390 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390)
3 0x000000000157d9a4 swift::GenericSignatureBuilder::addRequirement(swift::RequirementRepr const*, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::SubstitutionMap const*, swift::ModuleDecl*) (/path/to/swift/bin/swift+0x157d9a4)
4 0x000000000157bd6f swift::GenericSignatureBuilder::addConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*) (/path/to/swift/bin/swift+0x157bd6f)
5 0x000000000157fc55 swift::GenericSignatureBuilder::addTypeRequirement(llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::GenericSignatureBuilder::UnresolvedHandlingKind) (/path/to/swift/bin/swift+0x157fc55)
6 0x0000000001590d41 swift::GenericSignatureBuilder::ConstraintResult llvm::function_ref<swift::GenericSignatureBuilder::ConstraintResult (swift::Type, swift::TypeRepr const*)>::callback_fn<swift::GenericSignatureBuilder::addInheritedRequirements(swift::TypeDecl*, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::RequirementSource const*, swift::ModuleDecl*)::$_26>(long, swift::Type, swift::TypeRepr const*) (/path/to/swift/bin/swift+0x1590d41)
7 0x0000000001589522 std::_Function_handler<void (swift::Type, swift::TypeRepr const*), visitInherited(llvm::ArrayRef<swift::TypeLoc>, llvm::function_ref<swift::GenericSignatureBuilder::ConstraintResult (swift::Type, swift::TypeRepr const*)>)::$_59>::_M_invoke(std::_Any_data const&, swift::Type&&, swift::TypeRepr const*&&) (/path/to/swift/bin/swift+0x1589522)
8 0x000000000157b6a1 swift::GenericSignatureBuilder::addInheritedRequirements(swift::TypeDecl*, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::RequirementSource const*, swift::ModuleDecl*) (/path/to/swift/bin/swift+0x157b6a1)
9 0x000000000157b4be swift::GenericSignatureBuilder::addGenericParameterRequirements(swift::GenericTypeParamDecl*) (/path/to/swift/bin/swift+0x157b4be)
10 0x0000000001385a22 swift::TypeChecker::checkGenericParamList(swift::GenericSignatureBuilder*, swift::GenericParamList*, swift::GenericSignature*, swift::GenericTypeResolver*) (/path/to/swift/bin/swift+0x1385a22)
11 0x0000000001389004 swift::TypeChecker::checkGenericEnvironment(swift::GenericParamList*, swift::DeclContext*, swift::GenericSignature*, bool, llvm::function_ref<void (swift::GenericSignatureBuilder&)>) (/path/to/swift/bin/swift+0x1389004)
12 0x0000000001389429 swift::TypeChecker::validateGenericTypeSignature(swift::GenericTypeDecl*) (/path/to/swift/bin/swift+0x1389429)
13 0x000000000135a200 swift::TypeChecker::validateDecl(swift::ValueDecl*) (/path/to/swift/bin/swift+0x135a200)
14 0x0000000001359c99 swift::TypeChecker::validateDecl(swift::ValueDecl*) (/path/to/swift/bin/swift+0x1359c99)
15 0x00000000015b259c swift::DeclContext::lookupQualified(swift::Type, swift::DeclName, swift::NLOptions, swift::LazyResolver*, llvm::SmallVectorImpl<swift::ValueDecl*>&) const (/path/to/swift/bin/swift+0x15b259c)
16 0x00000000015b0c47 swift::UnqualifiedLookup::UnqualifiedLookup(swift::DeclName, swift::DeclContext*, swift::LazyResolver*, bool, swift::SourceLoc, bool, bool, bool) (/path/to/swift/bin/swift+0x15b0c47)
17 0x000000000138b607 swift::TypeChecker::lookupUnqualifiedType(swift::DeclContext*, swift::DeclName, swift::SourceLoc, swift::OptionSet<swift::NameLookupFlags, unsigned int>) (/path/to/swift/bin/swift+0x138b607)
18 0x00000000013dad5d resolveTopLevelIdentTypeComponent(swift::TypeChecker&, swift::DeclContext*, swift::ComponentIdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13dad5d)
19 0x00000000013d52b3 resolveIdentTypeComponent(swift::TypeChecker&, swift::DeclContext*, llvm::ArrayRef<swift::ComponentIdentTypeRepr*>, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d52b3)
20 0x00000000013d4c89 swift::TypeChecker::resolveIdentifierType(swift::DeclContext*, swift::IdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d4c89)
21 0x00000000013d59f8 (anonymous namespace)::TypeResolver::resolveType(swift::TypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>) (/path/to/swift/bin/swift+0x13d59f8)
22 0x00000000013d58fc swift::TypeChecker::resolveType(swift::TypeRepr*, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d58fc)
23 0x00000000013d4300 swift::TypeChecker::validateType(swift::TypeLoc&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d4300)
24 0x0000000001385c30 swift::TypeChecker::validateRequirement(swift::SourceLoc, swift::RequirementRepr&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*) (/path/to/swift/bin/swift+0x1385c30)
25 0x00000000013506d8 swift::TypeChecker::validateWhereClauses(swift::ProtocolDecl*) (/path/to/swift/bin/swift+0x13506d8)
26 0x0000000001353678 swift::TypeChecker::validateDeclForNameLookup(swift::ValueDecl*) (/path/to/swift/bin/swift+0x1353678)
27 0x00000000015b0b91 swift::UnqualifiedLookup::UnqualifiedLookup(swift::DeclName, swift::DeclContext*, swift::LazyResolver*, bool, swift::SourceLoc, bool, bool, bool) (/path/to/swift/bin/swift+0x15b0b91)
28 0x000000000138b607 swift::TypeChecker::lookupUnqualifiedType(swift::DeclContext*, swift::DeclName, swift::SourceLoc, swift::OptionSet<swift::NameLookupFlags, unsigned int>) (/path/to/swift/bin/swift+0x138b607)
29 0x00000000013dad5d resolveTopLevelIdentTypeComponent(swift::TypeChecker&, swift::DeclContext*, swift::ComponentIdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13dad5d)
30 0x00000000013d52b3 resolveIdentTypeComponent(swift::TypeChecker&, swift::DeclContext*, llvm::ArrayRef<swift::ComponentIdentTypeRepr*>, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d52b3)
31 0x00000000013d4c89 swift::TypeChecker::resolveIdentifierType(swift::DeclContext*, swift::IdentTypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, bool, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d4c89)
32 0x00000000013d59f8 (anonymous namespace)::TypeResolver::resolveType(swift::TypeRepr*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>) (/path/to/swift/bin/swift+0x13d59f8)
33 0x00000000013d58fc swift::TypeChecker::resolveType(swift::TypeRepr*, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d58fc)
34 0x00000000013d4300 swift::TypeChecker::validateType(swift::TypeLoc&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*, llvm::function_ref<bool (swift::TypeCheckRequest)>*) (/path/to/swift/bin/swift+0x13d4300)
35 0x0000000001385bfc swift::TypeChecker::validateRequirement(swift::SourceLoc, swift::RequirementRepr&, swift::DeclContext*, swift::OptionSet<swift::TypeResolutionFlags, unsigned int>, swift::GenericTypeResolver*) (/path/to/swift/bin/swift+0x1385bfc)
36 0x00000000013506d8 swift::TypeChecker::validateWhereClauses(swift::ProtocolDecl*) (/path/to/swift/bin/swift+0x13506d8)
37 0x0000000001369ecb (anonymous namespace)::DeclChecker::visitProtocolDecl(swift::ProtocolDecl*) (/path/to/swift/bin/swift+0x1369ecb)
38 0x0000000001358444 (anonymous namespace)::DeclChecker::visit(swift::Decl*) (/path/to/swift/bin/swift+0x1358444)
39 0x0000000001358343 swift::TypeChecker::typeCheckDecl(swift::Decl*, bool) (/path/to/swift/bin/swift+0x1358343)
40 0x00000000013e3344 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int, unsigned int) (/path/to/swift/bin/swift+0x13e3344)
41 0x0000000000fa16cd swift::CompilerInstance::performSema() (/path/to/swift/bin/swift+0xfa16cd)
42 0x00000000004abe59 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) (/path/to/swift/bin/swift+0x4abe59)
43 0x00000000004aa3f9 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) (/path/to/swift/bin/swift+0x4aa3f9)
44 0x0000000000465697 main (/path/to/swift/bin/swift+0x465697)
45 0x00007ff6235d5830 __libc_start_main /build/glibc-bfm8X4/glibc-2.23/csu/../csu/libc-start.c:325:0
46 0x0000000000462d39 _start (/path/to/swift/bin/swift+0x462d39)
```

Author: practicalswift

validation-test/compiler_crashers/28789-swift-genericsignaturebuilder-addrequirement-swift-requirementrepr-const-swift-g.swift

@@ -0,0 +1,9 @@
+// This source file is part of the Swift.org open source project
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+
+// RUN: not --crash %target-swift-frontend %s -emit-ir
+protocol P{{}class a typealias e where f=a