C++ TypePtr::canAssignTo方法代码示例

static bool isLiteralTypeForEnum(GlobalScope* global, const TypePtr& type)
{
    if(type->canAssignTo(global->IntegerLiteralConvertible()))
        return true;
    if(type->canAssignTo(global->StringLiteralConvertible()))
        return true;
    if(type->canAssignTo(global->FloatLiteralConvertible()))
        return true;
    //if(type->canAssignTo(global->BooleanLiteralConvertible))
    //    return true;
    if(type->canAssignTo(global->UnicodeScalarLiteralConvertible()))
        return true;
    if(type->canAssignTo(global->ExtendedGraphemeClusterLiteralConvertible()))
        return true;
    //nil, array, dictionary literal is not working for enum
    return false;
}

//.........这里部分代码省略.........

    assert(type != nullptr);
    assert(type->getCategory() == category);
    //prepare for generic
    if(!type->getGenericDefinition() && node->getGenericParametersDef())
    {
        GenericParametersDefPtr genericParams = node->getGenericParametersDef();
        GenericDefinitionPtr generic = prepareGenericTypes(genericParams);
        generic->registerTo(type->getScope());
        type->setGenericDefinition(generic);
    }
    
    if(node->hasModifier(DeclarationModifiers::Final))
        type->setFlags(SymbolFlagFinal, true);
    static_pointer_cast<TypeBuilder>(type)->setModuleName(ctx->currentModule->getName());
    ctx->allTypes.push_back(type);
    
    //check inheritance clause
    {
        TypePtr parent = nullptr;
        bool first = true;

        ScopeGuard scope(symbolRegistry, type->getScope());
        SCOPED_SET(ctx->currentType, type);
        for(const TypeIdentifierPtr& parentType : node->getParents())
        {
            parentType->accept(this);
            if(first)
                declareImmediately(parentType->getName());
            TypePtr ptr = resolveType(parentType, true);
            Type::Category pcategory = ptr->getCategory();
            if(pcategory == Type::Specialized)
                pcategory = ptr->getInnerType()->getCategory();
            if(pcategory == Type::Class && category == Type::Class)
            {
                if(!first)
                {
                    //only the first type can be class type
                    error(parentType, Errors::E_SUPERCLASS_MUST_APPEAR_FIRST_IN_INHERITANCE_CLAUSE_1, toString(parentType));
                    return nullptr;
                }
                parent = ptr;
                if(parent->hasFlags(SymbolFlagFinal))
                {
                    error(parentType, Errors::E_INHERITANCE_FROM_A_FINAL_CLASS_A_1, parentType->getName());
                    return nullptr;
                }
            }
            else if(category == Type::Enum && pcategory != Type::Protocol)
            {

                if(parent)//already has a raw type
                {
                    error(parentType, Errors::E_MULTIPLE_ENUM_RAW_TYPES_A_AND_B_2, parent->toString(), ptr->toString());
                    return nullptr;
                }
                if(!first)
                {
                    error(parentType, Errors::E_RAW_TYPE_A_MUST_APPEAR_FIRST_IN_THE_ENUM_INHERITANCE_CLAUSE_1, ptr->toString());
                    return nullptr;
                }
                //check if the raw type is literal convertible
                if(!isLiteralTypeForEnum(symbolRegistry->getGlobalScope(), ptr))
                {
                    error(parentType, Errors::E_RAW_TYPE_A_IS_NOT_CONVERTIBLE_FROM_ANY_LITERAL_1, ptr->toString());
                    return nullptr;
                }
                if(!ptr->canAssignTo(symbolRegistry->getGlobalScope()->Equatable()))
                {
                    error(parentType, Errors::E_RAWREPRESENTABLE_INIT_CANNOT_BE_SYNTHESIZED_BECAUSE_RAW_TYPE_A_IS_NOT_EQUATABLE_1, ptr->toString());
                    return nullptr;
                }
                parent = ptr;
            }
            else if(pcategory == Type::Protocol)
            {
                type->addProtocol(ptr);
            }
            else
            {
                if(category == Type::Class)
                    error(parentType, Errors::E_INHERITANCE_FROM_NONE_PROTOCOL_NON_CLASS_TYPE_1, toString(parentType));
                else
                    error(parentType, Errors::E_INHERITANCE_FROM_NONE_PROTOCOL_TYPE_1, toString(parentType));
                return nullptr;
            }
            first = false;
        }

        type->setParentType(parent);
        if(parent && parent->getAccessLevel() == AccessLevelPublic && (node->getModifiers() & DeclarationModifiers::AccessModifiers) == 0)
            type->setAccessLevel(AccessLevelPublic);//when access level is undefined, try to inherit base's access level
        else
            type->setAccessLevel(parseAccessLevel(node->getModifiers()));
    }
    

    declarationFinished(type->getName(), type, node);
    return type;
}

void DeclarationAnalyzer::visitEnum(const EnumDefPtr& node)
{
    if(isLazyDeclared(node))
        return;
    TypeBuilderPtr type = static_pointer_cast<TypeBuilder>(getOrDefineType(node));
    ScopeGuard scope(symbolRegistry, type->getScope());
    SCOPED_SET(ctx->currentType, type);
    SCOPED_SET(ctx->currentExtension, nullptr);
    SCOPED_SET(ctx->currentFunction, nullptr);


    GlobalScope* global = symbolRegistry->getGlobalScope();
    SymbolScope* local = symbolRegistry->getCurrentScope();
    //check if it's raw value enum
    bool isRawValues = false;
    if(node->numParents() > 0)
    {
        TypePtr firstParent = lookupType(node->getParent(0));
        if(firstParent)
        {
            Type::Category  category = firstParent->getCategory();
            isRawValues = category == Type::Struct || category == Type::Enum || category == Type::Aggregate || category == Type::Class;
            if(isRawValues)
                type->setParentType(firstParent);
        }
    }

    //initialize enum's cases
    if(isRawValues)
    {
        if(!node->numCases())
        {
            error(node, Errors::E_ENUM_WITH_NO_CASES_CANNOT_DECLARE_A_RAW_TYPE);
            return;
        }
        //Add RawRepresentable protocol if it's not implemented
        if(!type->canAssignTo(global->RawRepresentable()))
        {
            makeRawRepresentable(type, global);
        }

        TypePtr rawType = type->getParentType();
        assert(rawType != nullptr);
        bool integerConvertible = rawType->canAssignTo(global->IntegerLiteralConvertible());
        for(auto c : node->getCases())
        {
            if(!c.value && !integerConvertible)
            {
                //Enum cases require explicit raw values when the raw type is not integer literal convertible
                error(node, Errors::E_ENUM_CASES_REQUIRE_EXPLICIT_RAW_VALUES_WHEN_THE_RAW_TYPE_IS_NOT_INTEGER_LITERAL_CONVERTIBLE);
                return;
            }
            if(c.value)
            {
                if(dynamic_pointer_cast<TupleType>(c.value))
                {
                    error(node, Errors::E_ENUM_WITH_RAW_TYPE_CANNOT_HAVE_CASES_WITH_ARGUMENTS);
                    return;
                }
            }
            type->addEnumCase(c.name, global->Void());
            //register it to scope
            local->addSymbol(SymbolPlaceHolderPtr(new SymbolPlaceHolder(c.name, type, SymbolPlaceHolder::R_PARAMETER, SymbolFlagReadable | SymbolFlagMember | SymbolFlagStatic | SymbolFlagInitialized)));
        }
    }
    else
    {
        //it's an associated-values enum
        for(auto c : node->getCases())
        {
            TypePtr associatedType = global->Void();
            if(c.value)
            {
                TypeNodePtr typeNode = dynamic_pointer_cast<TypeNode>(c.value);
                if(!typeNode)
                {
                    error(node, Errors::E_ENUM_CASE_CANNOT_HAVE_A_RAW_VALUE_IF_THE_ENUM_DOES_NOT_HAVE_A_RAW_TYPE);
                    return;
                }
                assert(typeNode != nullptr);
                associatedType = resolveType(typeNode, true);
            }
            type->addEnumCase(c.name, associatedType);
            if(associatedType == global->Void())
                local->addSymbol(SymbolPlaceHolderPtr(new SymbolPlaceHolder(c.name, type, SymbolPlaceHolder::R_PARAMETER, SymbolFlagReadable | SymbolFlagMember | SymbolFlagStatic | SymbolFlagInitialized)));
        }
    }
    //check member declaration of enum
    {
        SCOPED_SET(ctx->flags, (ctx->flags & (~SemanticContext::FLAG_PROCESS_IMPLEMENTATION)) | SemanticContext::FLAG_PROCESS_DECLARATION);
        for (const DeclarationPtr &decl : *node)
        {
            bool isStatic = decl->hasModifier(DeclarationModifiers::Class) || decl->hasModifier(DeclarationModifiers::Static);
            if (!isStatic && (decl->getNodeType() == NodeType::ValueBindings))
            {
                error(node, Errors::E_ENUMS_MAY_NOT_CONTAIN_STORED_PROPERTIES);
                continue;
            }
            decl->accept(this);
        }
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    //check if it's defined as a nested type
    if(ctx->currentType)
    {
        if(genericParams)
        {
            error(node, Errors::E_GENERIC_TYPE_A_NESTED_IN_TYPE_B_IS_NOT_ALLOWED_2, id->getName(), ctx->currentType->getName());
            return nullptr;
        }
        if(ctx->currentType->isGenericType())
        {
            error(node, Errors::E_TYPE_A_NESTED_IN_GENERIC_TYPE_B_IS_NOT_ALLOWED_2, id->getName(), ctx->currentType->getName());
            return nullptr;
        }
    }

    if(genericParams)
    {
        generic = prepareGenericTypes(genericParams);
        generic->registerTo(typeScope);
    }

    //check inheritance clause
    TypePtr parent = nullptr;
    std::vector<TypePtr> protocols;
    bool first = true;

    for(const TypeIdentifierPtr& parentType : node->getParents())
    {
        parentType->accept(semanticAnalyzer);
        TypePtr ptr = this->lookupType(parentType);
        if(ptr->getCategory() == Type::Class && category == Type::Class)
        {
            if(!first)
            {
                //only the first type can be class type
                error(parentType, Errors::E_SUPERCLASS_MUST_APPEAR_FIRST_IN_INHERITANCE_CLAUSE_1, toString(parentType));
                return nullptr;
            }
            parent = ptr;
            if(parent->hasFlags(SymbolFlagFinal))
            {
                error(parentType, Errors::E_INHERITANCE_FROM_A_FINAL_CLASS_A_1, parentType->getName());
                return nullptr;
            }
        }
        else if(category == Type::Enum && ptr->getCategory() != Type::Protocol)
        {

            if(parent)//already has a raw type
            {
                error(parentType, Errors::E_MULTIPLE_ENUM_RAW_TYPES_A_AND_B_2, parent->toString(), ptr->toString());
                return nullptr;
            }
            if(!first)
            {
                error(parentType, Errors::E_RAW_TYPE_A_MUST_APPEAR_FIRST_IN_THE_ENUM_INHERITANCE_CLAUSE_1, ptr->toString());
                return nullptr;
            }
            //check if the raw type is literal convertible
            if(!isLiteralTypeForEnum(symbolRegistry->getGlobalScope(), ptr))
            {
                error(parentType, Errors::E_RAW_TYPE_A_IS_NOT_CONVERTIBLE_FROM_ANY_LITERAL_1, ptr->toString());
                return nullptr;
            }
            if(!ptr->canAssignTo(symbolRegistry->getGlobalScope()->Equatable()))
            {
                error(parentType, Errors::E_RAWREPRESENTABLE_INIT_CANNOT_BE_SYNTHESIZED_BECAUSE_RAW_TYPE_A_IS_NOT_EQUATABLE_1, ptr->toString());
                return nullptr;
            }
            parent = ptr;
        }
        else if(ptr->getCategory() == Type::Protocol)
        {
            protocols.push_back(ptr);
        }
        else
        {
            if(category == Type::Class)
                error(parentType, Errors::E_INHERITANCE_FROM_NONE_PROTOCOL_NON_CLASS_TYPE_1, toString(parentType));
            else
                error(parentType, Errors::E_INHERITANCE_FROM_NONE_PROTOCOL_TYPE_1, toString(parentType));
            return nullptr;
        }
        first = false;
    }

    //register this type
    type = Type::newType(node->getIdentifier()->getName(), category, node, parent, protocols, generic);
    node->setType(type);
    if(parent && parent->getAccessLevel() == AccessLevelPublic && (node->getModifiers() & DeclarationModifiers::AccessModifiers) == 0)
        type->setAccessLevel(AccessLevelPublic);//when access level is undefined, try to inherit base's access level
    else
        type->setAccessLevel(parseAccessLevel(node->getModifiers()));
    currentScope->addSymbol(type);
    if(node->hasModifier(DeclarationModifiers::Final))
        type->setFlags(SymbolFlagFinal, true);

    declarationFinished(type->getName(), type, node);
    return type;
}

void SemanticAnalyzer::visitValueBinding(const ValueBindingPtr& node)
{
    PatternPtr name = node->getName();
    //tuple was already exploded in declaration analyzer
    if(name->getNodeType() == NodeType::Tuple)
    {
        validateTupleTypeDeclaration(node);
    }
    if (name->getNodeType() != NodeType::Identifier)
        return;
    if(node->getOwner()->isReadOnly() && !node->getInitializer() && ctx->currentType == nullptr)
    {
        error(node, Errors::E_LET_REQUIRES_INITIALIZER);
        return;
    }
    //handle type inference for temporary variable
    if(node->isTemporary() && node->getInitializer())
    {
        //temporary variable always has an initializer
        TypePtr initializerType;
        TypePtr declaredType = node->getType();

        SCOPED_SET(ctx->contextualType, declaredType);
        node->getInitializer()->accept(this);
        initializerType = node->getInitializer()->getType();
        assert(initializerType != nullptr);

        if(declaredType)
        {
            //it has both type definition and initializer, then we need to check if the initializer expression matches the type annotation
            if(!initializerType->canAssignTo(declaredType))
            {
                error(node, Errors::E_CANNOT_CONVERT_EXPRESSION_TYPE_2, initializerType->toString(), declaredType->toString());
                return;
            }
        }
        else
        {
            node->setType(initializerType);
        }
    }
    

    //add implicitly constructor for Optional
    IdentifierPtr id = static_pointer_cast<Identifier>(node->getName());
    SymbolScope* currentScope = symbolRegistry->getCurrentScope();


    TypePtr declaredType = node->getType() ? node->getType() : lookupType(node->getDeclaredType());
    SCOPED_SET(ctx->contextualType, declaredType);
    if(!declaredType && !node->getInitializer())
    {
        error(node, Errors::E_TYPE_ANNOTATION_MISSING_IN_PATTERN);
        return;
    }
    SymbolPtr sym = currentScope->lookup(id->getIdentifier());
    assert(sym != nullptr);
    SymbolPlaceHolderPtr placeholder = std::dynamic_pointer_cast<SymbolPlaceHolder>(sym);
    assert(placeholder != nullptr);
    if(declaredType)
    {
        placeholder->setType(declaredType);
    }
    ExpressionPtr initializer = node->getInitializer();
    if(initializer)
    {
        placeholder->setFlags(SymbolFlagInitializing, true);
        ExpressionPtr initializer = transformExpression(declaredType, node->getInitializer());
        node->setInitializer(initializer);
        TypePtr actualType = initializer->getType();
        assert(actualType != nullptr);
        if(declaredType)
        {
            if(!Type::equals(actualType, declaredType) && !canConvertTo(initializer, declaredType))
            {
                error(initializer, Errors::E_CANNOT_CONVERT_EXPRESSION_TYPE_2, actualType->toString(), declaredType->toString());
                return;
            }
        }

        if(!declaredType)
            placeholder->setType(actualType);
    }
    assert(placeholder->getType() != nullptr);
    placeholder->setFlags(SymbolFlagInitializing, false);
    //optional type always considered initialized, compiler will make it has a default value nil
    TypePtr symbolType = sym->getType();
    GlobalScope* global = symbolRegistry->getGlobalScope();
    if(initializer || global->isOptional(symbolType) || global->isImplicitlyUnwrappedOptional(symbolType))
        markInitialized(placeholder);

    if (initializer)
        placeholder->setFlags(SymbolFlagHasInitializer, true);
    if(node->isTemporary())
    {
        placeholder->setFlags(SymbolFlagTemporary, true);
        markInitialized(placeholder);
    }

    if(!node->isTemporary())
//.........这里部分代码省略.........

void SemanticAnalyzer::validateTupleTypeDeclaration(const PatternPtr& name, const TypePtr& declType, const TypePtr& initType)
{
    switch(name->getNodeType())
    {
        case NodeType::Identifier:
        {
            if(initType && declType && !initType->canAssignTo(declType))
            {
                error(name, Errors::E_CANNOT_CONVERT_EXPRESSION_TYPE_2, initType->toString(), declType->toString());
            }
            break;
        }
        case NodeType::TypedPattern:
        {
            TypedPatternPtr pat = static_pointer_cast<TypedPattern>(name);
            assert(pat->getDeclaredType());
            TypePtr nameType = lookupType(pat->getDeclaredType());
            assert(nameType != nullptr);
            if(declType && !Type::equals(nameType, declType))
            {
                error(name, Errors::E_TYPE_ANNOTATION_DOES_NOT_MATCH_CONTEXTUAL_TYPE_A_1, declType->toString());
                abort();
                return;
            }

            break;
        }
        case NodeType::Tuple:
        {
            TuplePtr tuple = static_pointer_cast<Tuple>(name);
            if(declType)
            {
                if((declType->getCategory() != Type::Tuple) || (tuple->numElements() != declType->numElementTypes()))
                {
                    error(name, Errors::E_TYPE_ANNOTATION_DOES_NOT_MATCH_CONTEXTUAL_TYPE_A_1, declType->toString());
                    abort();
                    return;
                }
            }
            int elements = tuple->numElements();
            for(int i = 0; i < elements; i++)
            {
                PatternPtr element = tuple->getElement(i);
                TypePtr elementDecl = declType ? declType->getElementType(i) : nullptr;
                TypePtr elementInit = initType ? initType->getElementType(i) : nullptr;
                validateTupleTypeDeclaration(element, elementDecl, elementInit);
            }
            break;
        }
        case NodeType::ValueBindingPattern:
            break;
        case NodeType::EnumCasePattern:
        {
            
            break;
        }
        case NodeType::TypeCase:
        case NodeType::TypeCheck:
        default:
            error(name, Errors::E_EXPECT_TUPLE_OR_IDENTIFIER);
            break;
    }
    
}