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//===--- DerivedConformances.cpp - Derived conformance utilities ----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "TypeChecker.h"
#include "swift/AST/Decl.h"
#include "swift/AST/Stmt.h"
#include "swift/AST/Expr.h"
#include "swift/AST/Pattern.h"
#include "swift/AST/ParameterList.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/AST/Types.h"
#include "swift/ClangImporter/ClangModule.h"
#include "DerivedConformances.h"
using namespace swift;
DerivedConformance::DerivedConformance(TypeChecker &tc, Decl *conformanceDecl,
NominalTypeDecl *nominal,
ProtocolDecl *protocol)
: TC(tc), ConformanceDecl(conformanceDecl), Nominal(nominal),
Protocol(protocol) {
assert(getConformanceContext()->getSelfNominalTypeDecl() == nominal);
}
DeclContext *DerivedConformance::getConformanceContext() const {
return cast<DeclContext>(ConformanceDecl);
}
void DerivedConformance::addMembersToConformanceContext(
ArrayRef<Decl *> children) {
auto IDC = cast<IterableDeclContext>(ConformanceDecl);
for (auto child : children) {
IDC->addMember(child);
}
}
Type DerivedConformance::getProtocolType() const {
return Protocol->getDeclaredType();
}
bool DerivedConformance::derivesProtocolConformance(DeclContext *DC,
NominalTypeDecl *Nominal,
ProtocolDecl *Protocol) {
// Only known protocols can be derived.
auto knownProtocol = Protocol->getKnownProtocolKind();
if (!knownProtocol)
return false;
if (*knownProtocol == KnownProtocolKind::Hashable) {
// We can always complete a partial Hashable implementation, and we can
// synthesize a full Hashable implementation for structs and enums with
// Hashable components.
return canDeriveHashable(Nominal);
}
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::AdditiveArithmetic)
return canDeriveAdditiveArithmetic(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::PointwiseMultiplicative)
return canDerivePointwiseMultiplicative(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::ElementaryFunctions)
return canDeriveElementaryFunctions(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::KeyPathIterable)
return canDeriveKeyPathIterable(Nominal);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::TensorArrayProtocol)
return canDeriveTensorArrayProtocol(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::TensorGroup)
return canDeriveTensorGroup(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::VectorProtocol)
return canDeriveVectorProtocol(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::Differentiable)
return canDeriveDifferentiable(Nominal, DC);
// SWIFT_ENABLE_TENSORFLOW
if (*knownProtocol == KnownProtocolKind::EuclideanDifferentiable)
return canDeriveEuclideanDifferentiable(Nominal, DC);
if (auto *enumDecl = dyn_cast<EnumDecl>(Nominal)) {
switch (*knownProtocol) {
// The presence of a raw type is an explicit declaration that
// the compiler should derive a RawRepresentable conformance.
case KnownProtocolKind::RawRepresentable:
return enumDecl->hasRawType();
// Enums without associated values can implicitly derive Equatable
// conformance.
case KnownProtocolKind::Equatable:
return canDeriveEquatable(DC, Nominal);
// "Simple" enums without availability attributes can explicitly derive
// a CaseIterable conformance.
//
// FIXME: Lift the availability restriction.
case KnownProtocolKind::CaseIterable:
return !enumDecl->hasPotentiallyUnavailableCaseValue()
&& enumDecl->hasOnlyCasesWithoutAssociatedValues();
// @objc enums can explicitly derive their _BridgedNSError conformance.
case KnownProtocolKind::BridgedNSError:
return enumDecl->isObjC() && enumDecl->hasCases()
&& enumDecl->hasOnlyCasesWithoutAssociatedValues();
// Enums without associated values and enums with a raw type of String
// or Int can explicitly derive CodingKey conformance.
case KnownProtocolKind::CodingKey: {
Type rawType = enumDecl->getRawType();
if (rawType) {
auto parentDC = enumDecl->getDeclContext();
ASTContext &C = parentDC->getASTContext();
auto nominal = rawType->getAnyNominal();
return nominal == C.getStringDecl() || nominal == C.getIntDecl();
}
// hasOnlyCasesWithoutAssociatedValues will return true for empty enums;
// empty enumas are allowed to conform as well.
return enumDecl->hasOnlyCasesWithoutAssociatedValues();
}
default:
return false;
}
} else if (isa<StructDecl>(Nominal) || isa<ClassDecl>(Nominal)) {
// Structs and classes can explicitly derive Encodable and Decodable
// conformance (explicitly meaning we can synthesize an implementation if
// a type conforms manually).
if (*knownProtocol == KnownProtocolKind::Encodable ||
*knownProtocol == KnownProtocolKind::Decodable) {
// FIXME: This is not actually correct. We cannot promise to always
// provide a witness here for all structs and classes. Unfortunately,
// figuring out whether this is actually possible requires much more
// context -- a TypeChecker and the parent decl context at least -- and is
// tightly coupled to the logic within DerivedConformance.
// This unfortunately means that we expect a witness even if one will not
// be produced, which requires DerivedConformance::deriveCodable to output
// its own diagnostics.
return true;
}
// Structs can explicitly derive Equatable conformance.
if (isa<StructDecl>(Nominal)) {
switch (*knownProtocol) {
case KnownProtocolKind::Equatable:
return canDeriveEquatable(DC, Nominal);
default:
return false;
}
}
}
return false;
}
void DerivedConformance::tryDiagnoseFailedDerivation(DeclContext *DC,
NominalTypeDecl *nominal,
ProtocolDecl *protocol) {
auto knownProtocol = protocol->getKnownProtocolKind();
if (!knownProtocol)
return;
if (*knownProtocol == KnownProtocolKind::Equatable) {
tryDiagnoseFailedEquatableDerivation(DC, nominal);
}
if (*knownProtocol == KnownProtocolKind::Hashable) {
tryDiagnoseFailedHashableDerivation(DC, nominal);
}
}
ValueDecl *DerivedConformance::getDerivableRequirement(NominalTypeDecl *nominal,
ValueDecl *requirement) {
// Note: whenever you update this function, also update
// TypeChecker::deriveProtocolRequirement.
ASTContext &ctx = nominal->getASTContext();
auto name = requirement->getFullName();
// Local function that retrieves the requirement with the same name as
// the provided requirement, but within the given known protocol.
// SWIFT_ENABLE_TENSORFLOW
auto getRequirement = [&](KnownProtocolKind kind,
llvm::function_ref<bool(ValueDecl *)> filter =
nullptr) -> ValueDecl * {
// Dig out the protocol.
auto proto = ctx.getProtocol(kind);
if (!proto) return nullptr;
if (auto conformance = TypeChecker::conformsToProtocol(
nominal->getDeclaredInterfaceType(), proto, nominal,
ConformanceCheckFlags::SkipConditionalRequirements)) {
auto DC = conformance->getConcrete()->getDeclContext();
// Check whether this nominal type derives conformances to the protocol.
if (!DerivedConformance::derivesProtocolConformance(DC, nominal, proto))
return nullptr;
}
// Retrieve the requirement.
auto results = proto->lookupDirect(name);
// SWIFT_ENABLE_TENSORFLOW
// Filter requirements, if `filter` function is specified.
if (filter) {
llvm::erase_if(results, [&](ValueDecl *v) {
return !isa<ProtocolDecl>(v->getDeclContext()) ||
!v->isProtocolRequirement() || !filter(v);
});
}
return results.empty() ? nullptr : results.front();
// SWIFT_ENABLE_TENSORFLOW END
};
// Properties.
if (isa<VarDecl>(requirement)) {
// RawRepresentable.rawValue
if (name.isSimpleName(ctx.Id_rawValue))
return getRequirement(KnownProtocolKind::RawRepresentable);
// Hashable.hashValue
if (name.isSimpleName(ctx.Id_hashValue))
return getRequirement(KnownProtocolKind::Hashable);
// CaseIterable.allValues
if (name.isSimpleName(ctx.Id_allCases))
return getRequirement(KnownProtocolKind::CaseIterable);
// _BridgedNSError._nsErrorDomain
if (name.isSimpleName(ctx.Id_nsErrorDomain))
return getRequirement(KnownProtocolKind::BridgedNSError);
// CodingKey.stringValue
if (name.isSimpleName(ctx.Id_stringValue))
return getRequirement(KnownProtocolKind::CodingKey);
// CodingKey.intValue
if (name.isSimpleName(ctx.Id_intValue))
return getRequirement(KnownProtocolKind::CodingKey);
// SWIFT_ENABLE_TENSORFLOW
// AdditiveArithmetic.zero
if (name.isSimpleName(ctx.Id_zero))
return getRequirement(KnownProtocolKind::AdditiveArithmetic);
// SWIFT_ENABLE_TENSORFLOW
// EuclideanDifferentiable.differentiableVectorView
if (name.isSimpleName(ctx.Id_differentiableVectorView))
return getRequirement(KnownProtocolKind::EuclideanDifferentiable);
// SWIFT_ENABLE_TENSORFLOW
// PointwiseMultiplicative.one
if (name.isSimpleName(ctx.Id_one))
return getRequirement(KnownProtocolKind::PointwiseMultiplicative);
// SWIFT_ENABLE_TENSORFLOW
// PointwiseMultiplicative.reciprocal
if (name.isSimpleName(ctx.Id_reciprocal))
return getRequirement(KnownProtocolKind::PointwiseMultiplicative);
// SWIFT_ENABLE_TENSORFLOW
// KeyPathIterable.allKeyPaths
if (name.isSimpleName(ctx.Id_allKeyPaths))
return getRequirement(KnownProtocolKind::KeyPathIterable);
// SWIFT_ENABLE_TENSORFLOW
// TensorArrayProtocol._tensorHandleCount
if (name.isSimpleName(ctx.Id_tensorHandleCount))
return getRequirement(KnownProtocolKind::TensorArrayProtocol);
// SWIFT_ENABLE_TENSORFLOW
// TensorArrayProtocol._typeList
if (name.isSimpleName(ctx.Id_typeList) && !requirement->isStatic())
return getRequirement(KnownProtocolKind::TensorArrayProtocol);
// SWIFT_ENABLE_TENSORFLOW
// TensorGroup._typeList
if (name.isSimpleName(ctx.Id_typeList))
return getRequirement(KnownProtocolKind::TensorGroup);
return nullptr;
}
// Functions.
if (auto func = dyn_cast<FuncDecl>(requirement)) {
if (func->isOperator() && name.getBaseName() == "==")
return getRequirement(KnownProtocolKind::Equatable);
// Encodable.encode(to: Encoder)
if (name.isCompoundName() && name.getBaseName() == ctx.Id_encode) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_to)
return getRequirement(KnownProtocolKind::Encodable);
}
// Hashable.hash(into: inout Hasher)
if (name.isCompoundName() && name.getBaseName() == ctx.Id_hash) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 && argumentNames[0] == ctx.Id_into)
return getRequirement(KnownProtocolKind::Hashable);
}
// SWIFT_ENABLE_TENSORFLOW
// AdditiveArithmetic.+
// AdditiveArithmetic.-
if (func->isOperator() && (name.getBaseName() == "+" ||
name.getBaseName() == "-")) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 2)
return getRequirement(KnownProtocolKind::AdditiveArithmetic);
}
// SWIFT_ENABLE_TENSORFLOW
// PointwiseMultiplicative.(.*)
if (func->isOperator() && name.getBaseName() == ".*") {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 2)
return getRequirement(KnownProtocolKind::PointwiseMultiplicative);
}
// SWIFT_ENABLE_TENSORFLOW
// ElementaryFunctions requirements
if (name.isCompoundName()) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 && (false
#define ELEMENTARY_FUNCTION_UNARY(ID, NAME) || name.getBaseName() == NAME
#include "DerivedConformanceElementaryFunctions.def"
#undef ELEMENTARY_FUNCTION_UNARY
)) {
return getRequirement(KnownProtocolKind::ElementaryFunctions);
}
if (argumentNames.size() == 2) {
if (name.getBaseName() == "root")
return getRequirement(KnownProtocolKind::ElementaryFunctions);
if (name.getBaseName() == "pow") {
return getRequirement(
KnownProtocolKind::ElementaryFunctions,
[&](ValueDecl *v) {
auto *funcDecl = dyn_cast<FuncDecl>(v);
if (!funcDecl)
return false;
return funcDecl->getParameters()->get(1)->getName() ==
func->getParameters()->get(1)->getName();
});
}
}
}
// SWIFT_ENABLE_TENSORFLOW
// VectorProtocol.scaled(by:)
if (name.isCompoundName() && name.getBaseName() == ctx.Id_scaled) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 &&
argumentNames[0] == ctx.getIdentifier("by"))
return getRequirement(KnownProtocolKind::VectorProtocol);
}
// SWIFT_ENABLE_TENSORFLOW
// VectorProtocol.adding(_:)
// VectorProtocol.subtracting(_:)
if (name.isCompoundName() &&
(name.getBaseName() == ctx.Id_adding ||
name.getBaseName() == ctx.Id_subtracting)) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 && argumentNames[0].empty())
return getRequirement(KnownProtocolKind::VectorProtocol);
}
// SWIFT_ENABLE_TENSORFLOW
// TensorArrayProtocol._unpackTensorHandles(into:)
if (name.isCompoundName() &&
name.getBaseName() == ctx.Id_unpackTensorHandles) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 &&
argumentNames[0] == ctx.getIdentifier("into")) {
return getRequirement(KnownProtocolKind::TensorArrayProtocol);
}
}
// SWIFT_ENABLE_TENSORFLOW
// Differentiable.move(along:)
if (name.isCompoundName() &&
name.getBaseName() == ctx.Id_move) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1 &&
argumentNames[0] == ctx.getIdentifier("along")) {
return getRequirement(KnownProtocolKind::Differentiable);
}
}
return nullptr;
}
// Initializers.
if (auto ctor = dyn_cast<ConstructorDecl>(requirement)) {
auto argumentNames = name.getArgumentNames();
if (argumentNames.size() == 1) {
if (argumentNames[0] == ctx.Id_rawValue)
return getRequirement(KnownProtocolKind::RawRepresentable);
// CodingKey.init?(stringValue:), CodingKey.init?(intValue:)
if (ctor->isFailable() &&
!ctor->isImplicitlyUnwrappedOptional() &&
(argumentNames[0] == ctx.Id_stringValue ||
argumentNames[0] == ctx.Id_intValue))
return getRequirement(KnownProtocolKind::CodingKey);
// Decodable.init(from: Decoder)
if (argumentNames[0] == ctx.Id_from)
return getRequirement(KnownProtocolKind::Decodable);
// SWIFT_ENABLE_TENSORFLOW
// TensorGroup.init(_owning:)
if (argumentNames[0] == ctx.getIdentifier("_owning")) {
return getRequirement(KnownProtocolKind::TensorGroup);
}
} else if (argumentNames.size() == 2) {
// SWIFT_ENABLE_TENSORFLOW
// TensorArrayProtocol.init(_owning:count)
if (argumentNames[0] == ctx.getIdentifier("_owning") &&
argumentNames[1] == ctx.getIdentifier("count")) {
return getRequirement(KnownProtocolKind::TensorArrayProtocol);
}
}
return nullptr;
}
// Associated types.
if (isa<AssociatedTypeDecl>(requirement)) {
// RawRepresentable.RawValue
if (name.isSimpleName(ctx.Id_RawValue))
return getRequirement(KnownProtocolKind::RawRepresentable);
// CaseIterable.AllCases
if (name.isSimpleName(ctx.Id_AllCases))
return getRequirement(KnownProtocolKind::CaseIterable);
// SWIFT_ENABLE_TENSORFLOW
// KeyPathIterable.AllKeyPaths
if (name.isSimpleName(ctx.Id_AllKeyPaths))
return getRequirement(KnownProtocolKind::KeyPathIterable);
// SWIFT_ENABLE_TENSORFLOW
// Differentiable.TangentVector
if (name.isSimpleName(ctx.Id_TangentVector))
return getRequirement(KnownProtocolKind::Differentiable);
// SWIFT_ENABLE_TENSORFLOW
// VectorProtocol.VectorSpaceScalar
if (name.isSimpleName(ctx.Id_VectorSpaceScalar))
return getRequirement(KnownProtocolKind::VectorProtocol);
return nullptr;
}
return nullptr;
}
DeclRefExpr *
DerivedConformance::createSelfDeclRef(AbstractFunctionDecl *fn) {
ASTContext &C = fn->getASTContext();
auto selfDecl = fn->getImplicitSelfDecl();
return new (C) DeclRefExpr(selfDecl, DeclNameLoc(), /*implicit*/true);
}
AccessorDecl *DerivedConformance::
addGetterToReadOnlyDerivedProperty(VarDecl *property,
Type propertyContextType) {
auto getter =
declareDerivedPropertyGetter(property, propertyContextType);
property->setImplInfo(StorageImplInfo::getImmutableComputed());
property->setAccessors(SourceLoc(), {getter}, SourceLoc());
return getter;
}
std::pair<AccessorDecl *, AccessorDecl *>
DerivedConformance::addGetterAndSetterToMutableDerivedProperty(
VarDecl *property, Type propertyContextType) {
auto *getter = declareDerivedPropertyGetter(property, propertyContextType);
auto *setter = declareDerivedPropertySetter(property, propertyContextType);
property->setImplInfo(StorageImplInfo::getMutableComputed());
property->setAccessors(SourceLoc(), {getter, setter}, SourceLoc());
return std::make_pair(getter, setter);
}
AccessorDecl *
DerivedConformance::declareDerivedPropertyGetter(VarDecl *property,
Type propertyContextType) {
auto &C = property->getASTContext();
auto parentDC = property->getDeclContext();
ParameterList *params = ParameterList::createEmpty(C);
Type propertyInterfaceType = property->getInterfaceType();
auto getterDecl = AccessorDecl::create(C,
/*FuncLoc=*/SourceLoc(), /*AccessorKeywordLoc=*/SourceLoc(),
AccessorKind::Get, property,
/*StaticLoc=*/SourceLoc(), StaticSpellingKind::None,
/*Throws=*/false, /*ThrowsLoc=*/SourceLoc(),
/*GenericParams=*/nullptr, params,
TypeLoc::withoutLoc(propertyInterfaceType), parentDC);
getterDecl->setImplicit();
getterDecl->setIsTransparent(false);
// Compute the interface type of the getter.
getterDecl->computeType();
getterDecl->copyFormalAccessFrom(property);
C.addSynthesizedDecl(getterDecl);
return getterDecl;
}
// SWIFT_ENABLE_TENSORFLOW
AccessorDecl *
DerivedConformance::declareDerivedPropertySetter(VarDecl *property,
Type propertyContextType) {
bool isStatic = property->isStatic();
bool isFinal = property->isFinal();
auto &C = property->getASTContext();
auto parentDC = property->getDeclContext();
auto propertyInterfaceType = property->getInterfaceType();
auto propertyParam = new (C) ParamDecl(SourceLoc(), SourceLoc(), Identifier(),
property->getLoc(), C.getIdentifier("newValue"), parentDC);
propertyParam->setSpecifier(ParamDecl::Specifier::Default);
propertyParam->setInterfaceType(propertyInterfaceType);
ParameterList *params = ParameterList::create(C, propertyParam);
auto setterDecl = AccessorDecl::create(C,
/*FuncLoc*/ SourceLoc(), /*AccessorKeywordLoc*/ SourceLoc(),
AccessorKind::Set, property, /*StaticLoc*/ SourceLoc(),
StaticSpellingKind::None, /*Throws*/ false, /*ThrowsLoc*/ SourceLoc(),
/*GenericParams*/ nullptr, params, TypeLoc(), parentDC);
setterDecl->setImplicit();
setterDecl->setStatic(isStatic);
// Set mutating if parent is not a class.
if (!parentDC->getSelfClassDecl())
setterDecl->setSelfAccessKind(SelfAccessKind::Mutating);
// If this is supposed to be a final method, mark it as such.
assert(isFinal || !parentDC->getSelfClassDecl());
if (isFinal && parentDC->getSelfClassDecl() &&
!setterDecl->isFinal())
setterDecl->getAttrs().add(new (C) FinalAttr(/*Implicit*/ true));
// Compute the interface type of the setter.
setterDecl->setGenericSignature(parentDC->getGenericSignatureOfContext());
setterDecl->computeType();
setterDecl->copyFormalAccessFrom(property);
C.addSynthesizedDecl(setterDecl);
return setterDecl;
}
std::pair<VarDecl *, PatternBindingDecl *>
DerivedConformance::declareDerivedProperty(Identifier name,
Type propertyInterfaceType,
Type propertyContextType,
bool isStatic, bool isFinal) {
auto &C = TC.Context;
auto parentDC = getConformanceContext();
VarDecl *propDecl = new (C) VarDecl(/*IsStatic*/isStatic, VarDecl::Introducer::Var,
/*IsCaptureList*/false, SourceLoc(), name,
parentDC);
// SWIFT_ENABLE_TENSORFLOW
// TODO: Upstream this change to master.
if (isFinal && parentDC->getSelfClassDecl())
propDecl->getAttrs().add(new (C) FinalAttr(/*Implicit*/ true));
propDecl->setImplicit();
propDecl->copyFormalAccessFrom(Nominal, /*sourceIsParentContext*/ true);
propDecl->setInterfaceType(propertyInterfaceType);
Pattern *propPat = new (C) NamedPattern(propDecl, /*implicit*/ true);
propPat->setType(propertyContextType);
propPat = TypedPattern::createImplicit(C, propPat, propertyContextType);
propPat->setType(propertyContextType);
auto *pbDecl = PatternBindingDecl::createImplicit(
C, StaticSpellingKind::None, propPat, /*InitExpr*/ nullptr, parentDC);
return {propDecl, pbDecl};
}
bool DerivedConformance::checkAndDiagnoseDisallowedContext(
ValueDecl *synthesizing) const {
// In general, conformances can't be synthesized in extensions across files;
// but we have to allow it as a special case for Equatable and Hashable on
// enums with no associated values to preserve source compatibility.
bool allowCrossfileExtensions = false;
if (Protocol->isSpecificProtocol(KnownProtocolKind::Equatable) ||
Protocol->isSpecificProtocol(KnownProtocolKind::Hashable)) {
auto ED = dyn_cast<EnumDecl>(Nominal);
allowCrossfileExtensions = ED && ED->hasOnlyCasesWithoutAssociatedValues();
}
if (!allowCrossfileExtensions &&
Nominal->getModuleScopeContext() !=
getConformanceContext()->getModuleScopeContext()) {
TC.diagnose(ConformanceDecl->getLoc(),
diag::cannot_synthesize_in_crossfile_extension,
getProtocolType());
TC.diagnose(Nominal->getLoc(), diag::kind_declared_here,
DescriptiveDeclKind::Type);
return true;
}
// A non-final class can't have an protocol-witnesss initializer in an
// extension.
if (auto CD = dyn_cast<ClassDecl>(Nominal)) {
if (!CD->isFinal() && isa<ConstructorDecl>(synthesizing) &&
isa<ExtensionDecl>(ConformanceDecl)) {
TC.diagnose(ConformanceDecl->getLoc(),
diag::cannot_synthesize_init_in_extension_of_nonfinal,
getProtocolType(), synthesizing->getFullName());
return true;
}
}
return false;
}