Now it is far less actual, since even text editors can infer types via language servers in many langs, and you don’t need to put that information in the name. Might be still useful for langs where type inferring is not easy and you want to help users to guess what they receive.

Oh :) I miss the point. Have had some debates in my early programming life about «is» and now read your post with my own accents :))

Saw some code styles where «is» prefix is an indicator of bool-like type in loosely typed programming languages. Also that kind of guidelines can be written when syntax highlighting is not so common. For example there is pretty common to have «m» prefix for protected members in same old code styles.

О, помню, что думал втащить эту фичу (занятие незалогином) в LinguaLeo, но не хватило настойчивости. В целом и хорошо, что не хватило :)