protocol: inappropriateMatching result code

[Hallvard B Furuseth <h.b.furuseth@usit.uio.no>]

When is the inappropriateMatching result code returned?
Its description in Appendix A says:

     Indicates that an attempt was made, e.g. in a filter, to use
     a matching rule not defined for the attribute type concerned.

This text is roughly copied from X.511 section 12.4.

However, [Protocol] Section 4.5.1 (Search Request) implies that this
does not return an error, but just causes entries to be ignored:

- The extensibleMatch description says:
     If the type field is present and the matchingRule is present,
     (...) the matchingRule MUST be one
     suitable for use with the specified type (see [Syntaxes]),
     otherwise the filter item is undefined.

- A bit earlier, the section says:
     If the filter evaluates
     to FALSE or Undefined, then the entry is ignored for the search.

- Other ways to use extensibleMatch (like ...:dn:matchingrule:=val,
  which might pass an attribute value to an inappropriate matching
  rule) don't say that the result is undefined and non-error the
  same way, but it seems implied that they work the same way.

OTOH, I imagine the result code could be returned for e.g.:
- an unrecognized extensibleMatch matching rule,
- extensibleMatch with neither matching rule nor attribute type,
- equality match on an attribute with no EQUALITY matching rule.

-- 
Hallvard