Bogus property type narrowing when calling impure function

[dktapps]

Bug report

This is an edge case I discovered while testing for a different bug in 1.4.1.

Code snippet that reproduces the problem

https://phpstan.org/r/09325d79-56ea-417e-825d-0314ebd22a19

Expected output

No error should be reported: not all values have been covered in the match, since the impure function call could result in a value change.

[dktapps]

Forgive the confusing default match arm, this is a distilled sample of code from PM... the point is that it shouldn't be reported as an error.

[dktapps]

This error is also sometimes accompanied by this on the last match arm for some reason:

 ------ ----------------------------------------------------------------------
  Line   src\network\mcpe\handler\InGamePacketHandler.php
 ------ ----------------------------------------------------------------------
  814    Match arm comparison between 4 and 4 is always true.

I've yet to identify what makes this show up; all I do know is that removing the default case shuts it up, but that's not an option.

[phpstan-bot]

@dktapps After the latest push in 1.11.x, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 8.0 – 8.1 (1 error)
+PHP 8.0 – 8.1 (2 errors)
 ==========
 
+51: Match arm comparison between 1|2|3|4 and 0 is always false.
 56: Match arm is unreachable because previous comparison is always true.
 
 PHP 7.1 – 7.4 (11 errors)

Full report

PHP 8.0 – 8.1 (2 errors)

Line	Error
51	`Match arm comparison between 1
56	Match arm is unreachable because previous comparison is always true.

PHP 7.1 – 7.4 (11 errors)

Line	Error
51	Syntax error, unexpected ',' on line 51
51	Syntax error, unexpected T_DOUBLE_ARROW on line 51
52	Syntax error, unexpected ',' on line 52
52	Syntax error, unexpected T_DOUBLE_ARROW on line 52
53	Syntax error, unexpected ',' on line 53
53	Syntax error, unexpected T_DOUBLE_ARROW on line 53
54	Syntax error, unexpected ',' on line 54
54	Syntax error, unexpected T_DOUBLE_ARROW on line 54
55	Syntax error, unexpected ',' on line 55
55	Syntax error, unexpected T_DOUBLE_ARROW on line 55
57	Syntax error, unexpected '}' on line 57

[dktapps]

This new result seems more broken than before

[ondrejmirtes]

Fixed: phpstan/phpstan-src#2787

[dktapps]

Nothing showing from the issue bot?

[ondrejmirtes]

Issue bot does not comment on closed issues.

[dktapps]

Right, I checked the latest result and it seems to be all green. Thanks!

[github-actions]

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.