After a discussion with @spicyj we decided to keep the warning even though the functions will throw in production. The warning is the only way to learn about that.

We should also document how to pass the secret through in case you know what you're doing.

if (!isNode(entry[1])) {
                return false;
              }
            }
          }
        }
      } else {
        return false;
      }
      return true;
    default:
      return false;
  }
}
function isSymbol(propType, propValue) {
  
  if (propType === 'symbol') {
    return true;
  }
  
  if (propValue['@@toStringTag'] === 'Symbol') {
    return true;
  }
  
  if (typeof Symbol === 'function' && propValue instanceof Symbol) {
    return true;
  }
  return false;
}
function getPropType(propValue) {