I agree it looks weird without parens, but it really depends on the grammar definition of the type syntax. Does ~ have a lower precedence of |?

I ran a quick test but it seems phpdoc parser does not accept ~

I agree it looks weird without parens, but it really depends on the grammar definition of the type syntax. Does ~ have a lower precedence of |?

The answer is no, type like A~(false|null)|Z is currently rendered like A~false|null|Z. This is simply an unimplemented feature in the describe.

@mvorisek After the latest push in 2.0.x, PHPStan now reports different result with your code snippet:

@@ @@
-8: Dumped type: mixed~0|0.0|''|'0'|array{}|false|null
+PHP 8.0 – 8.3 (1 error)
+==========
+
+8: Dumped type: mixed~0|0.0|''|'0'|array{}|false|null
+
+PHP 7.2 – 7.4 (3 errors)
+==========
+
+5: Parameter $arr of method HelloWorld::test() has invalid type mixed.
+7: Variable $arr in empty() always exists and is not falsy.
+8: Dumped type: mixed

Implemented phpstan/phpstan-src#3360

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.