The following is with eslint-plugin-react@6.10.3.

If a propType is quoted for some reason like this:

MyComponent.propTypes = {
  'data-id': PropTypes.string,
};

Then the require-default-props rule gives the following warning:

propType "undefined" is not required, but has no corresponding defaultProp declaration.

Howwever, giving the propType a default value like this does satisfy the rule:

MyComponent.defaultProps = {
  'data-id': 'test',
};

It seems like this is an issue with the formatting of the error message.