bool recordIsTriviallyDefaultConstructible(const RecordDecl &RecordDecl,
const ASTContext &Context) {
const auto *ClassDecl = dyn_cast<CXXRecordDecl>(&RecordDecl);
// Non-C++ records are always trivially constructible.
if (!ClassDecl)
return true;
// A class with a user-provided default constructor is not trivially
// constructible.
if (ClassDecl->hasUserProvidedDefaultConstructor())
return false;
// A class is trivially constructible if it has a trivial default constructor.
if (ClassDecl->hasTrivialDefaultConstructor())
return true;
// If all its fields are trivially constructible.
for (const FieldDecl *Field : ClassDecl->fields()) {
if (!isTriviallyDefaultConstructible(Field->getType(), Context))
return false;
}
// If all its direct bases are trivially constructible.
for (const CXXBaseSpecifier &Base : ClassDecl->bases()) {
if (!isTriviallyDefaultConstructible(Base.getType(), Context))
return false;
}
return true;
}
// Based on QualType::isTrivial.
bool isTriviallyDefaultConstructible(QualType Type, const ASTContext &Context) {
if (Type.isNull())
return false;
if (Type->isArrayType())
return isTriviallyDefaultConstructible(Context.getBaseElementType(Type),
Context);
// Return false for incomplete types after skipping any incomplete array
// types which are expressly allowed by the standard and thus our API.
if (Type->isIncompleteType())
return false;
if (Context.getLangOpts().ObjCAutoRefCount) {
switch (Type.getObjCLifetime()) {
case Qualifiers::OCL_ExplicitNone:
return true;
case Qualifiers::OCL_Strong:
case Qualifiers::OCL_Weak:
case Qualifiers::OCL_Autoreleasing:
return false;
case Qualifiers::OCL_None:
if (Type->isObjCLifetimeType())
return false;
break;
}
}
QualType CanonicalType = Type.getCanonicalType();
if (CanonicalType->isDependentType())
return false;
// As an extension, Clang treats vector types as Scalar types.
if (CanonicalType->isScalarType() || CanonicalType->isVectorType())
return true;
if (const auto *RT = CanonicalType->getAs<RecordType>()) {
return recordIsTriviallyDefaultConstructible(*RT->getDecl(), Context);
}
// No other types can match.
return false;
}
void RedundantMemberInitCheck::registerMatchers(MatchFinder *Finder) {
auto Construct =
cxxConstructExpr(
hasDeclaration(cxxConstructorDecl(hasParent(
cxxRecordDecl(unless(isTriviallyDefaultConstructible()))))))
.bind("construct");
Finder->addMatcher(
cxxConstructorDecl(
unless(isDelegatingConstructor()),
ofClass(unless(
anyOf(isUnion(), ast_matchers::isTemplateInstantiation()))),
forEachConstructorInitializer(
cxxCtorInitializer(isWritten(),
withInitializer(ignoringImplicit(Construct)),
unless(forField(hasType(isConstQualified()))))
.bind("init"))),
this);
}
