It's a little strange for the "otherwise" case to not cover all cases not covered by the previous rule. This reordering makes it stranger by moving the complete-class context part away from the other member-secification pieces.

How about something like:

A class is complete where its definition is reachable, and in complete-class contexts within its member-specification. Otherwise it is incomplete, including in other parts of its member-specification.

Yeah, sounds better. Updated.

@tkoeppe?

Very good, thank you!

I think a constructive rule is better:

A class is complete:

• at the point where its definition is reachable, or
• in complete-class contexts within its member-specification

Otherwise it is incomplete, including in other parts of its member-specification.

Why do you think that's better than the previous suggestion? The sentence seems short enough to not require a list, and also I don't think the "or" is right: a class is really complete in both cases, not just in "at least one of these cases". "Or" would be appropriate if we said, "In order to be complete, a class has to [either X] or [Y]", but as written, "and" seems more appropriate.

Mike M. says that "complete-class context" is already applying to "within its member-specification" per the definition, so the extra normative mention of "within its member-specification" is superfluous.

However, this is now deviating from the existing words quite a bit, so I'm wondering whether we want a brief trip through CWG.

I think the "within the member-specification" should be removed in both "otherwise case" and "complete-class contexts". We have completely defined what complete-class context is:

A complete-class context of a class (template) is a

• [...]

within the member-specification of the class or class template.

This implies, e.g., that the function body of the member function outside of the member-specification is not a complete-class context. Conversely, when we refer to "complete-class context", we are saying the contexts defined in the list that appears in the member-specification of the class. Hence

A class is considered to be complete either:

• at the point where its definition is reachable, or
• in its complete-class contexts

Otherwise, it is incomplete.

This is clear, I think.

For and in the updated wording, I still think "and" can result in ambiguity. How should we parse that wording?

A class is complete

1. Where its definition is reachable && in its complete-class contexts
2. Where its definition is reachable || in its complete-class contexts

Case 1 is not the intent but it can embody what and here means. Obviously, the class is considered to be complete if merely one of the conditions is achieved. So, constructive wording is appreciated here to avoid ambiguity.

a class is really complete in both cases, not just in "at least one of these cases". "Or" would be appropriate if we said, "In order to be complete, a class has to [either X] or [Y]", but as written, "and" seems more appropriate.

For and in the updated wording, I still think "and" can result in ambiguity. How should we parse that wording?

Mind you, the current wording uses "and also", which is correct.

Where does "and also" appear in the current wording? The current wording is just ambiguous due to its "and".

Oh, I was looking at the diff of this PR, which added "also".