Type
	SimpleType
		Projection
			prefix : SimpleType
			id: String
		ParameterRef
			id: Int
		Singleton
			path: Path
		EmptyType
		Parameterized
			baseType : SimpleType
			typeArguments: Type*
	Annotated
		baseType : SimpleType
		annotations : Annotation*
	Structure
		parents : ~Type*
		declared: ~Definition*
		inherited: ~Definition*
	Existential
		baseType : Type
		clause: TypeParameter*
	Polymorphic
		baseType: Type
		parameters: TypeParameter*