[class.this]p4 is the constraint that constructors/destructors do not have cv-qualifiers. It probably belong better in [class.mfct.non-static] after its p4, that talks about cv-qualifiers on non-static member functions.

p5 talks about ref-qualifiers on non-static member functions, and I don't see anything stating that this does not apply to ctors/dtors. If that falls out of the grammar, then perhaps this cv-restriction would go the same way, and this paragraph should be demoted to a note? Otherwise, there may be a CWG issue needs to be opened on ref-qualifiers on constructors? (Just as likely I missed this restriction in another cross-reference, in which case it would be good to call that out here too.)