static Type deriveCaseIterable_AllCases(DerivedConformance &derived) {
// enum SomeEnum : CaseIterable {
// @derived
// typealias AllCases = [SomeEnum]
// }
auto *rawInterfaceType = computeAllCasesType(cast<EnumDecl>(derived.Nominal));
return derived.getConformanceContext()->mapTypeIntoContext(rawInterfaceType);
}
/// Validates the given CodingKeys enum decl by ensuring its cases are a 1-to-1
/// match with the stored vars of the given type.
///
/// \param codingKeysDecl The \c CodingKeys enum decl to validate.
static bool validateCodingKeysEnum(DerivedConformance &derived,
EnumDecl *codingKeysDecl) {
auto &tc = derived.TC;
auto conformanceDC = derived.getConformanceContext();
// Look through all var decls in the given type.
// * Filter out lazy/computed vars.
// * Filter out ones which are present in the given decl (by name).
//
// If any of the entries in the CodingKeys decl are not present in the type
// by name, then this decl doesn't match.
// If there are any vars left in the type which don't have a default value
// (for Decodable), then this decl doesn't match.
// Here we'll hold on to properties by name -- when we've validated a property
// against its CodingKey entry, it will get removed.
llvm::SmallDenseMap<Identifier, VarDecl *, 8> properties;
for (auto *varDecl :
derived.Nominal->getStoredProperties(/*skipInaccessible=*/true)) {
if (varDecl->getAttrs().hasAttribute<LazyAttr>())
continue;
properties[varDecl->getName()] = varDecl;
}
bool propertiesAreValid = true;
for (auto elt : codingKeysDecl->getAllElements()) {
auto it = properties.find(elt->getName());
if (it == properties.end()) {
tc.diagnose(elt->getLoc(), diag::codable_extraneous_codingkey_case_here,
elt->getName());
// TODO: Investigate typo-correction here; perhaps the case name was
// misspelled and we can provide a fix-it.
propertiesAreValid = false;
continue;
}
// We have a property to map to. Ensure it's {En,De}codable.
auto conformance =
varConformsToCodable(tc, conformanceDC, it->second, derived.Protocol);
switch (conformance) {
case Conforms:
// The property was valid. Remove it from the list.
properties.erase(it);
break;
case DoesNotConform:
tc.diagnose(it->second->getLoc(),
diag::codable_non_conforming_property_here,
derived.getProtocolType(), it->second->getType());
LLVM_FALLTHROUGH;
case TypeNotValidated:
// We don't produce a diagnostic for a type which failed to validate.
// This will produce a diagnostic elsewhere anyway.
propertiesAreValid = false;
continue;
}
}
if (!propertiesAreValid)
return false;
// If there are any remaining properties which the CodingKeys did not cover,
// we can skip them on encode. On decode, though, we can only skip them if
// they have a default value.
if (!properties.empty() &&
derived.Protocol->isSpecificProtocol(KnownProtocolKind::Decodable)) {
for (auto it = properties.begin(); it != properties.end(); ++it) {
// If the var is default initializable, then it need not have an explicit
// initial value.
auto *varDecl = it->second;
if (auto pbd = varDecl->getParentPatternBinding()) {
if (pbd->isDefaultInitializable())
continue;
}
if (varDecl->getParentInitializer())
continue;
// The var was not default initializable, and did not have an explicit
// initial value.
propertiesAreValid = false;
tc.diagnose(it->second->getLoc(), diag::codable_non_decoded_property_here,
derived.getProtocolType(), it->first);
}
}
return propertiesAreValid;
}
/// Returns whether the given type has a valid nested \c CodingKeys enum.
///
/// If the type has an invalid \c CodingKeys entity, produces diagnostics to
/// complain about the error. In this case, the error result will be true -- in
/// the case where we don't have a valid CodingKeys enum and have produced
/// diagnostics here, we don't want to then attempt to synthesize a CodingKeys
/// enum.
///
/// \returns A \c CodingKeysValidity value representing the result of the check.
static CodingKeysValidity hasValidCodingKeysEnum(DerivedConformance &derived) {
auto &tc = derived.TC;
auto &C = tc.Context;
auto codingKeysDecls =
derived.Nominal->lookupDirect(DeclName(C.Id_CodingKeys));
if (codingKeysDecls.empty())
return CodingKeysValidity(/*hasType=*/false, /*isValid=*/true);
// Only ill-formed code would produce multiple results for this lookup.
// This would get diagnosed later anyway, so we're free to only look at the
// first result here.
auto result = codingKeysDecls.front();
auto *codingKeysTypeDecl = dyn_cast<TypeDecl>(result);
if (!codingKeysTypeDecl) {
tc.diagnose(result->getLoc(),
diag::codable_codingkeys_type_is_not_an_enum_here,
derived.getProtocolType());
return CodingKeysValidity(/*hasType=*/true, /*isValid=*/false);
}
// If the decl hasn't been validated yet, do so.
tc.validateDecl(codingKeysTypeDecl);
// CodingKeys may be a typealias. If so, follow the alias to its canonical
// type.
auto codingKeysType = codingKeysTypeDecl->getDeclaredInterfaceType();
if (isa<TypeAliasDecl>(codingKeysTypeDecl))
codingKeysTypeDecl = codingKeysType->getAnyNominal();
// Ensure that the type we found conforms to the CodingKey protocol.
auto *codingKeyProto = C.getProtocol(KnownProtocolKind::CodingKey);
if (!tc.conformsToProtocol(codingKeysType, codingKeyProto,
derived.getConformanceContext(),
ConformanceCheckFlags::Used)) {
// If CodingKeys is a typealias which doesn't point to a valid nominal type,
// codingKeysTypeDecl will be nullptr here. In that case, we need to warn on
// the location of the usage, since there isn't an underlying type to
// diagnose on.
SourceLoc loc = codingKeysTypeDecl ?
codingKeysTypeDecl->getLoc() :
cast<TypeDecl>(result)->getLoc();
tc.diagnose(loc, diag::codable_codingkeys_type_does_not_conform_here,
derived.getProtocolType());
return CodingKeysValidity(/*hasType=*/true, /*isValid=*/false);
}
// CodingKeys must be an enum for synthesized conformance.
auto *codingKeysEnum = dyn_cast<EnumDecl>(codingKeysTypeDecl);
if (!codingKeysEnum) {
tc.diagnose(codingKeysTypeDecl->getLoc(),
diag::codable_codingkeys_type_is_not_an_enum_here,
derived.getProtocolType());
return CodingKeysValidity(/*hasType=*/true, /*isValid=*/false);
}
bool valid = validateCodingKeysEnum(derived, codingKeysEnum);
return CodingKeysValidity(/*hasType=*/true, /*isValid=*/valid);
}
/// Returns whether the given type is valid for synthesizing {En,De}codable.
///
/// Checks to see whether the given type has a valid \c CodingKeys enum, and if
/// not, attempts to synthesize one for it.
///
/// \param requirement The requirement we want to synthesize.
static bool canSynthesize(DerivedConformance &derived, ValueDecl *requirement) {
// Before we attempt to look up (or more importantly, synthesize) a CodingKeys
// entity on target, we need to make sure the type is otherwise valid.
//
// If we are synthesizing Decodable and the target is a class with a
// superclass, our synthesized init(from:) will need to call either
// super.init(from:) or super.init() depending on whether the superclass is
// Decodable itself.
//
// If the required initializer is not available, we shouldn't attempt to
// synthesize CodingKeys.
auto &tc = derived.TC;
ASTContext &C = tc.Context;
auto proto = derived.Protocol;
auto *classDecl = dyn_cast<ClassDecl>(derived.Nominal);
if (proto->isSpecificProtocol(KnownProtocolKind::Decodable) && classDecl) {
if (auto *superclassDecl = classDecl->getSuperclassDecl()) {
DeclName memberName;
auto superType = superclassDecl->getDeclaredInterfaceType();
if (tc.conformsToProtocol(superType, proto, superclassDecl,
ConformanceCheckFlags::Used)) {
// super.init(from:) must be accessible.
memberName = cast<ConstructorDecl>(requirement)->getFullName();
} else {
// super.init() must be accessible.
// Passing an empty params array constructs a compound name with no
// arguments (as opposed to a simple name when omitted).
memberName = DeclName(C, DeclBaseName::createConstructor(),
ArrayRef<Identifier>());
}
auto result = tc.lookupMember(superclassDecl, superType, memberName);
if (result.empty()) {
// No super initializer for us to call.
tc.diagnose(superclassDecl, diag::decodable_no_super_init_here,
requirement->getFullName(), memberName);
return false;
} else if (result.size() > 1) {
// There are multiple results for this lookup. We'll end up producing a
// diagnostic later complaining about duplicate methods (if we haven't
// already), so just bail with a general error.
return false;
} else {
auto *initializer =
cast<ConstructorDecl>(result.front().getValueDecl());
auto conformanceDC = derived.getConformanceContext();
if (!initializer->isDesignatedInit()) {
// We must call a superclass's designated initializer.
tc.diagnose(initializer,
diag::decodable_super_init_not_designated_here,
requirement->getFullName(), memberName);
return false;
} else if (!initializer->isAccessibleFrom(conformanceDC)) {
// Cannot call an inaccessible method.
auto accessScope = initializer->getFormalAccessScope(conformanceDC);
tc.diagnose(initializer, diag::decodable_inaccessible_super_init_here,
requirement->getFullName(), memberName,
accessScope.accessLevelForDiagnostics());
return false;
} else if (initializer->getFailability() != OTK_None) {
// We can't call super.init() if it's failable, since init(from:)
// isn't failable.
tc.diagnose(initializer, diag::decodable_super_init_is_failable_here,
requirement->getFullName(), memberName);
return false;
}
}
}
}
// If the target already has a valid CodingKeys enum, we won't need to
// synthesize one.
auto validity = hasValidCodingKeysEnum(derived);
// We found a type, but it wasn't valid.
if (!validity.isValid)
return false;
// We can try to synthesize a type here.
if (!validity.hasType) {
auto *synthesizedEnum = synthesizeCodingKeysEnum(derived);
if (!synthesizedEnum)
return false;
}
return true;
}