public function addAlternate(PhpType $alternate)
{
// build() returns the bottom type by default, so we can
// just bail out early here.
if ($alternate->isNoType()) {
return $this;
}
$this->isAllType = $this->isAllType || $alternate->isAllType();
$isAlternateUnknown = $alternate instanceof UnknownType;
// instanceof is desired here
$this->isNativeUnknownType = $this->isNativeUnknownType || $isAlternateUnknown;
if ($isAlternateUnknown) {
$this->areAllUnknownsChecked = $this->areAllUnknownsChecked && $alternate->isChecked();
}
if (!$this->isAllType && !$this->isNativeUnknownType) {
if ($alternate->isUnionType()) {
$union = $alternate->toMaybeUnionType();
foreach ($union->getAlternates() as $unionAlt) {
$this->addAlternate($unionAlt);
}
} else {
// Look through the alternates we've got so far,
// and check if any of them are duplicates of
// one another.
foreach ($this->alternates as $index => $current) {
// The Unknown type is special in that we cannot use our
// subtype based check, but need to check for equality to
// avoid duplicates, and not remove all other alternates.
if ($alternate->isUnknownType()) {
if ($alternate->equals($current)) {
return $this;
}
continue;
}
// Check if we already have a more general type in the union.
// Then, we do not add this alternate.
if ($alternate->isSubTypeOf($current)) {
return $this;
}
// Check if we have a subtype of the passed alternate. Then,
// we remove that alternate in favor of the newly passed one.
if ($current->isSubTypeOf($alternate)) {
unset($this->alternates[$index]);
}
}
$this->alternates[] = $alternate;
}
}
return $this;
}
/**
* Computes the restricted types given a non-successful shallow equality comparison.
*
* @return PhpType[] The first element is the restricted this type, the second element is the restricted type of the
* passed type.
*/
public function getTypesUnderShallowInequality(PhpType $that)
{
// union types
if ($that->isUnionType()) {
$p = $that->toMaybeUnionType()->getTypesUnderShallowInequality($this);
return array($p[1], $p[0]);
}
// Other types.
// There are only two types whose shallow inequality is deterministically
// true -- null and false. We can just enumerate them. Should we ever add
// a true type, this needs to be added here as well.
if ($this->isNullType() && $that->isNullType()) {
return array(null, null);
}
if ($this->isFalse() && $that->isFalse()) {
return array(null, null);
}
return array($this, $that);
}