a typeRefT refers to a class, a basic type or a type parameter

#id: id
the unique ID assigned to this fact.

#parent: id
the ID of the fact that represents the parent of this fact in the prolog AST.

#encl: methodT, constructorT, classInitializerT, fieldT, classT, annotationMemberT, annotationT
the ID of the fact that represents the enclosing element.

#referencedType: classT, basicTypeT, typeParamT
the ID of the referenced type.

String m() {                                                             
    ...
}

methodT(#meth, ..., 'm', [], #typeref, [], ...).
typeRefT(#typeref, #meth, #meth, #string).
classT(#string, ..., 'String', ...).

ast_node_def('Java',typeRefT,[
     ast_arg(id,      mult(1,1,no ), id, [typeRefT]),
     ast_arg(parent,  mult(1,1,no ), id, [id]),
     ast_arg(encl,    mult(1,1,no ), id, [methodT, constructorT, classInitializerT,fieldT,classT,annotationMemberT,annotationT]),
     ast_arg(typeRef, mult(1,1,no ), id, [classT,basicTypeT,typeParamT])
]).