[swiftc (52 vs. 5592)] Add crasher in swift::TypeBase::getCanonicalType(...)

Add test case for crash triggered in `swift::TypeBase::getCanonicalType(...)`.

Current number of unresolved compiler crashers: 52 (5592 resolved)

/cc @slavapestov - just wanted to let you know that this crasher caused an assertion failure for the assertion `gpDecl->getDepth() != GenericTypeParamDecl::InvalidDepth && "parameter hasn't been validated"` added on 2017-02-22 by you in commit fdb0a18 :-)

Assertion failure in [`lib/AST/Type.cpp (line 1086)`](https://github.com/apple/swift/blob/c1139c0b0cc1cc0bd7bc089d67dd08f6c241904f/lib/AST/Type.cpp#L1086):

```
Assertion `gpDecl->getDepth() != GenericTypeParamDecl::InvalidDepth && "parameter hasn't been validated"' failed.

When executing: swift::CanType swift::TypeBase::getCanonicalType()
```

Assertion context:

```c++

  case TypeKind::GenericTypeParam: {
    GenericTypeParamType *gp = cast<GenericTypeParamType>(this);
    auto gpDecl = gp->getDecl();
    assert(gpDecl->getDepth() != GenericTypeParamDecl::InvalidDepth &&
           "parameter hasn't been validated");
    Result = GenericTypeParamType::get(gpDecl->getDepth(), gpDecl->getIndex(),
                                       gpDecl->getASTContext());
    break;
  }

```
Stack trace:

```
0 0x0000000003e849d4 PrintStackTraceSignalHandler(void*) (/path/to/swift/bin/swift+0x3e849d4)
1 0x0000000003e84d16 SignalHandler(int) (/path/to/swift/bin/swift+0x3e84d16)
2 0x00007f6adc82e390 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x11390)
3 0x00007f6adad53428 gsignal /build/glibc-bfm8X4/glibc-2.23/signal/../sysdeps/unix/sysv/linux/raise.c:54:0
4 0x00007f6adad5502a abort /build/glibc-bfm8X4/glibc-2.23/stdlib/abort.c:91:0
5 0x00007f6adad4bbd7 __assert_fail_base /build/glibc-bfm8X4/glibc-2.23/assert/assert.c:92:0
6 0x00007f6adad4bc82 (/lib/x86_64-linux-gnu/libc.so.6+0x2dc82)
7 0x00000000016c6c70 swift::TypeBase::getCanonicalType() (/path/to/swift/bin/swift+0x16c6c70)
8 0x00000000016c6eac swift::QuerySubstitutionMap::operator()(swift::SubstitutableType*) const (/path/to/swift/bin/swift+0x16c6eac)
9 0x00000000016d4519 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<llvm::Optional<swift::ProtocolConformanceRef> (swift::CanType, swift::Type, swift::ProtocolType*)>, swift::SubstOptions)::$_18>(long, swift::TypeBase*) (/path/to/swift/bin/swift+0x16d4519)
10 0x00000000016d0a56 swift::Type::transformRec(llvm::function_ref<llvm::Optional<swift::Type> (swift::TypeBase*)>) const (/path/to/swift/bin/swift+0x16d0a56)
11 0x00000000016d0d6d swift::Type::transformRec(llvm::function_ref<llvm::Optional<swift::Type> (swift::TypeBase*)>) const (/path/to/swift/bin/swift+0x16d0d6d)
12 0x00000000016cbd45 swift::Type::subst(swift::SubstitutionMap const&, swift::SubstOptions) const (/path/to/swift/bin/swift+0x16cbd45)
13 0x000000000166e75e swift::GenericSignatureBuilder::addRequirement(swift::Requirement const&, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::ModuleDecl*, swift::SubstitutionMap const*) (/path/to/swift/bin/swift+0x166e75e)
14 0x000000000166f67f swift::GenericSignatureBuilder::expandConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*, bool)::$_15::operator()(swift::TypeDecl*, swift::TypeDecl*) const (/path/to/swift/bin/swift+0x166f67f)
15 0x000000000166e04f swift::GenericSignatureBuilder::expandConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*, bool) (/path/to/swift/bin/swift+0x166e04f)
16 0x0000000001670fba 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+0x1670fba)
17 0x0000000001686173 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*)::$_22>(long, swift::Type, swift::TypeRepr const*) (/path/to/swift/bin/swift+0x1686173)
18 0x000000000167dda2 std::_Function_handler<void (swift::Type, swift::TypeRepr const*), visitInherited(llvm::ArrayRef<swift::TypeLoc>, llvm::function_ref<swift::GenericSignatureBuilder::ConstraintResult (swift::Type, swift::TypeRepr const*)>)::$_56>::_M_invoke(std::_Any_data const&, swift::Type&&, swift::TypeRepr const*&&) (/path/to/swift/bin/swift+0x167dda2)
19 0x000000000166c72e swift::GenericSignatureBuilder::addInheritedRequirements(swift::TypeDecl*, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::RequirementSource const*, swift::ModuleDecl*) (/path/to/swift/bin/swift+0x166c72e)
20 0x000000000166cd29 swift::GenericSignatureBuilder::expandConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*, bool) (/path/to/swift/bin/swift+0x166cd29)
21 0x0000000001670fba 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+0x1670fba)
22 0x0000000001686173 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*)::$_22>(long, swift::Type, swift::TypeRepr const*) (/path/to/swift/bin/swift+0x1686173)
23 0x000000000167dda2 std::_Function_handler<void (swift::Type, swift::TypeRepr const*), visitInherited(llvm::ArrayRef<swift::TypeLoc>, llvm::function_ref<swift::GenericSignatureBuilder::ConstraintResult (swift::Type, swift::TypeRepr const*)>)::$_56>::_M_invoke(std::_Any_data const&, swift::Type&&, swift::TypeRepr const*&&) (/path/to/swift/bin/swift+0x167dda2)
24 0x000000000166c72e swift::GenericSignatureBuilder::addInheritedRequirements(swift::TypeDecl*, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::RequirementSource const*, swift::ModuleDecl*) (/path/to/swift/bin/swift+0x166c72e)
25 0x000000000166ca45 swift::GenericSignatureBuilder::expandConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*, bool) (/path/to/swift/bin/swift+0x166ca45)
26 0x0000000001670fba 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+0x1670fba)
27 0x0000000001686173 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*)::$_22>(long, swift::Type, swift::TypeRepr const*) (/path/to/swift/bin/swift+0x1686173)
28 0x000000000167dda2 std::_Function_handler<void (swift::Type, swift::TypeRepr const*), visitInherited(llvm::ArrayRef<swift::TypeLoc>, llvm::function_ref<swift::GenericSignatureBuilder::ConstraintResult (swift::Type, swift::TypeRepr const*)>)::$_56>::_M_invoke(std::_Any_data const&, swift::Type&&, swift::TypeRepr const*&&) (/path/to/swift/bin/swift+0x167dda2)
29 0x000000000166c72e swift::GenericSignatureBuilder::addInheritedRequirements(swift::TypeDecl*, llvm::PointerUnion<swift::GenericSignatureBuilder::PotentialArchetype*, swift::Type>, swift::GenericSignatureBuilder::RequirementSource const*, swift::ModuleDecl*) (/path/to/swift/bin/swift+0x166c72e)
30 0x000000000166cd29 swift::GenericSignatureBuilder::expandConformanceRequirement(swift::GenericSignatureBuilder::PotentialArchetype*, swift::ProtocolDecl*, swift::GenericSignatureBuilder::RequirementSource const*, bool) (/path/to/swift/bin/swift+0x166cd29)
31 0x0000000001670fba 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+0x1670fba)
32 0x000000000166e93b swift::GenericSignatureBuilder::addRequirement(swift::Requirement const&, swift::GenericSignatureBuilder::FloatingRequirementSource, swift::ModuleDecl*, swift::SubstitutionMap const*) (/path/to/swift/bin/swift+0x166e93b)
33 0x0000000001638efc swift::ProtocolDecl::computeRequirementSignature() (/path/to/swift/bin/swift+0x1638efc)
34 0x00000000012c2a48 swift::TypeChecker::validateGenericTypeSignature(swift::GenericTypeDecl*) (/path/to/swift/bin/swift+0x12c2a48)
35 0x0000000001290473 swift::TypeChecker::validateDecl(swift::ValueDecl*) (/path/to/swift/bin/swift+0x1290473)
36 0x00000000012a18cf (anonymous namespace)::DeclChecker::visitProtocolDecl(swift::ProtocolDecl*) (/path/to/swift/bin/swift+0x12a18cf)
37 0x000000000128e5b8 (anonymous namespace)::DeclChecker::visit(swift::Decl*) (/path/to/swift/bin/swift+0x128e5b8)
38 0x000000000128e4b3 swift::TypeChecker::typeCheckDecl(swift::Decl*, bool) (/path/to/swift/bin/swift+0x128e4b3)
39 0x000000000131efc4 swift::performTypeChecking(swift::SourceFile&, swift::TopLevelContext&, swift::OptionSet<swift::TypeCheckingFlags, unsigned int>, unsigned int, unsigned int, unsigned int, unsigned int) (/path/to/swift/bin/swift+0x131efc4)
40 0x0000000001043dd7 swift::CompilerInstance::performSema() (/path/to/swift/bin/swift+0x1043dd7)
41 0x00000000004bd856 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) (/path/to/swift/bin/swift+0x4bd856)
42 0x00000000004bc60e swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) (/path/to/swift/bin/swift+0x4bc60e)
43 0x0000000000474c54 main (/path/to/swift/bin/swift+0x474c54)
44 0x00007f6adad3e830 __libc_start_main /build/glibc-bfm8X4/glibc-2.23/csu/../csu/libc-start.c:325:0
45 0x0000000000472509 _start (/path/to/swift/bin/swift+0x472509)
```

Author: practicalswift

validation-test/compiler_crashers/28838-gpdecl-getdepth-generictypeparamdecl-invaliddepth-parameter-hasnt-been-validated.swift

@@ -0,0 +1,12 @@
+// 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
+
+// REQUIRES: asserts
+// RUN: not --crash %target-swift-frontend %s -emit-ir
+protocol P{typealias e:A
+protocol A:P{}typealias a
+class a<a