English Wikipedia has hundreds of thousands of disambiguation pages. Ideally, no link should ever be made pointing directly to a disambiguation page at a primary topic title; the link should point to the actual article. For example, "the probe went to [[Mercury]]" should actually say "the probe went to [[Mercury (planet)|Mercury)]]"; if the link is intentional, it should pipe through a "foo (disambiguation)" redirect, as in, "there are many meanings of the word, [[Mercury (disambiguation)|Mercury]]". Despite intensive and longstanding efforts at correction, the number of incorrect links hovers around 150,000, with constant repair efforts being offset by the constant introduction of new errors.
I therefore propose the creation of a notification system that would provide a pop-up alert or a warning screen to an editor, indicating that an edit they have made and are attempting to save in Article, Template, Category, Portal, or Draft space will create a link to a disambiguation page, rather than their intended target article. The notice would appear something like:
Warning: this edit will create a link to the disambiguation page, [[Mercury]]; if you intend to link to a specific meaning of Mercury, please correct the link so that it points to the article covering that meaning. If you intend to point to the disambiguation page, please pipe your link as [[Mercury (disambiguation)|Mercury]].
In a truly ideal world, the editor would then be offered a dropdown menu of possible meanings of "Mercury", and would be able to fix the link (and proceed with the save) by making one click to select the intended meaning. Whether such a dropdown menu is possible or not, the editor should have a chance to continue on to save the document as is, and to make the correction afterward.
If it is not possible to implement this with respect to all disambiguation pages, it would still be very useful if such a system could be implemented with respect to a few hundred of the disambiguation pages that are most commonly linked. These can be readily identified by disambiguators, and will include disambiguation pages for terms that ambiguously refer to both nationalities and widely-spoken languages (English, Spanish, Chinese, etc.), terms that refer both to popular music genres and to other popular cultural or scientific topics (Rock, Pop, Heavy metal, etc.), terms that refer to popular or frequently referenced place names having other meanings (Georgia, Phoenix, Springfield, etc.), and terms having multiple scientific and popular culture meanings (Mercury, Battery, Spring, Seal, Model, etc.).
See also: T198936: If a user adds a link to a disambiguation page in the mainspace, suggest changing the link