/**
* Visit a node with kind `\ast\AST_DIM`
*
* @param Node $node
* A node of the type indicated by the method name that we'd
* like to figure out the type that it produces.
*
* @return UnionType
* The set of types that are possibly produced by the
* given node
*/
public function visitDim(Node $node) : UnionType
{
$union_type = UnionType::fromNode($this->context, $this->code_base, $node->children['expr']);
if ($union_type->isEmpty()) {
return new UnionType();
}
// Figure out what the types of accessed array
// elements would be
$generic_types = $union_type->genericArrayElementTypes();
// If we have generics, we're all set
if (!$generic_types->isEmpty()) {
return $generic_types;
}
// If the only type is null, we don't know what
// accessed items will be
if ($union_type->isType(NullType::instance())) {
return new UnionType();
}
$element_types = new UnionType();
// You can access string characters via array index,
// so we'll add the string type to the result if we're
// indexing something that could be a string
if ($union_type->isType(StringType::instance()) || $union_type->canCastToUnionType(StringType::instance()->asUnionType())) {
$element_types->addType(StringType::instance());
}
// array offsets work on strings, unfortunately
// Double check that any classes in the type don't
// have ArrayAccess
$array_access_type = Type::fromNamespaceAndName('\\', 'ArrayAccess');
// Hunt for any types that are viable class names and
// see if they inherit from ArrayAccess
foreach ($union_type->getTypeList() as $type) {
if ($type->isNativeType()) {
continue;
}
$class_fqsen = FullyQualifiedClassName::fromType($type);
// If we can't find the class, the type probably
// wasn't a class.
if (!$this->code_base->hasClassWithFQSEN($class_fqsen)) {
continue;
}
$clazz = $this->code_base->getClassByFQSEN($class_fqsen);
// If the class has type ArrayAccess, it can be indexed
// as if it were an array. That being said, we still don't
// know the types of the elements, but at least we don't
// error out.
if ($clazz->getUnionType()->hasType($array_access_type)) {
return $element_types;
}
}
if ($element_types->isEmpty()) {
Log::err(Log::ETYPE, "Suspicious array access to {$union_type}", $this->context->getFile(), $node->lineno);
}
return $element_types;
}
/**
* Takes "a|b[]|c|d[]|e" and returns "b|d"
*
* @return UnionType
* The subset of types in this
*/
public function genericArrayElementTypes() : UnionType
{
// If array is in there, then it can be any type
// Same for mixed
if ($this->hasType(ArrayType::instance()) || $this->hasType(MixedType::instance())) {
return MixedType::instance()->asUnionType();
}
if ($this->hasType(ArrayType::instance())) {
return NullType::instance()->asUnionType();
}
return new UnionType(array_filter(array_map(function (Type $type) {
if (!$type->isGenericArray()) {
return null;
}
return $type->genericArrayElementType();
}, $this->getTypeList())));
}
public function testEvaluate()
{
$object = new NullType();
$this->assertNull($object->evaluate(['unused']));
}
