Currently we don't define "related type" as a term, and it has different meanings in different contexts. It may be confusing to use "related type" because some readers may think it should be a term and consistently refer to the same thing (see cplusplus/CWG#461).

Could you add references to the occurrences of "related types" here? Thanks.

@jensmaurer Sure, here are all 6 references/uses of the term that I could find.

1. temp.class.general
2. support.general
3. char.traits.general
4. re.req
   5 & 6) dcl.init.ref The example given in dcl.init.ref#5.4.4 has 2 uses of the term related type

Originally posted by @ranaanoop in cplusplus/CWG#461 (comment)