A type representing a boolean.
Descriptor representing a collection or compound type of collection object.
This descriptor represents any type that is capable of containing other typed values. Examples of such
types can be an array, DoctrineCollection or ArrayObject.
This class represents any Type that could not be identified.
Sometimes DocBlocks refer to types, such as classes, that are outside the generated project's scope; in these
cases we want to identify them as such with an unknown type descriptor.