There is the approved RFC at https://wiki.php.net/rfc/context_sensitive_lexer which is listed as "pending implementation" which should alleviate these BC breaks significantly. The linked RFC mentions this one specifically under the "Impact On Other RFCs" section.
- [PHP-DEV] Re: [RFC] Reserving More Types in PHP 7 Nate Abele
- Re: [PHP-DEV] Re: [RFC] Reserving More Types in P... Levi Morrison
- [PHP-DEV] Re: [RFC] Reserving More Types in P... Nate Abele
- Re: [PHP-DEV] Re: [RFC] Reserving More Ty... Joshua Holmer
- Re: [PHP-DEV] Re: [RFC] Reserving Mor... Marcio Almada
- Re: [PHP-DEV] Re: [RFC] Reserving More Ty... Stanislav Malyshev
- Re: [PHP-DEV] Re: [RFC] Reserving Mor... Benjamin Eberlei
- Re: [PHP-DEV] Re: [RFC] Reservin... Lester Caine
- Re: [PHP-DEV] Re: [RFC] Reservin... Matteo Beccati
- RE: [PHP-DEV] Re: [RFC] Reserving Mor... François Laupretre
- Re: [PHP-DEV] Re: [RFC] Reservin... Rowan Collins
- Re: [PHP-DEV] Re: [RFC] Rese... Johannes Schlüter
- RE: [PHP-DEV] Re: [RFC] Rese... François Laupretre
- Re: [PHP-DEV] Re: [RFC] ... Rowan Collins