HHVM & Hack solved two big problems that made PHP difficult for Facebook and other large companies with large existing PHP codebases: Speed, and the lack of type checking

Now the PHP ecosystem is more mature – PHP 7 eliminated the speed differences between HHVM and PHP, and a bunch of static analysis tools find 95% of the bugs that HHVM's typechecker finds.

It makes sense that this would be an inflection point for the future of HHVM.

I hope that more features from HHVM make it into PHP core – especially property types and generics – because, whatever FB decides to do with HHVM, PHP is here for the long-haul.

If you are a PHP user and use Intellij/Phpstorm then this https://plugins.jetbrains.com/plugin/7622-php-inspections-ea... is utterly incredible.

It catches so much stuff, I've been using PHP since 2009 and it there was still stuff I was doing day to day it flagged me for, it's not only that it makes you write better code but it catches so much stuff that you no longer have to hold in your head (things like "Method throws an unhandled exception" etc).

In terms of "wow" (impact vs amount of effort required) it's second only to TypeScript in the last year or so for me.

Not a co-incidence that both tools add better type checking (amongst a lot of other useful stuff) to the languages I was stuck using.

Unfortunately, you can't force everyone to use it (especially given its price). That's why a bunch of people have written separate PHP static analysis tools:

Phan (https://github.com/phan/phan), PHPStan (https://github.com/phpstan/phpstan) and Psalm (https://github.com/vimeo/psalm), the last of which I created.