function getCurrentComponentErrorInfo(parentType) {
	  var info = getDeclarationErrorAddendum();

	  if (!info) {
	    var parentName = typeof parentType === 'string' ? parentType : parentType.displayName || parentType.name;
	    if (parentName) {
	      info = ' Check the top-level render call using <' + parentName + '>.';
	    }
	  }
	  return info;
	}
Warn if there's no key explicitly set on dynamic arrays of children or
object keys are not valid. This allows us to keep track of children between
updates.