docs: private TypeSignature getTypeSignature() {
          if (typeSignature == null) {
              try {
                  // There can't be any type variables to resolve in either ClassRefTypeSignature or
                  // BaseTypeSignature, so just set definingClassName to null
                  typeSignature = TypeSignature.parse(typeDescriptorStr, /* definingClassName = */ null);
                  typeSignature.setScanResult(scanResult);
              } catch (final ParseException e) {
                  throw new IllegalArgumentException(e);
              }
          }
          return typeSignature;
      }