code: public Type unboxedType(Type t) {
          for (int i=0; i<syms.boxedName.length; i++) {
              Name box = syms.boxedName[i];
              if (box != null &&
                  asSuper(t, syms.enterClass(syms.java_base, box)) != null)
                  return syms.typeOfTag[i];
          }
          return Type.noType;
      }
docs: Return the primitive type corresponding to a boxed type.