incorrect type narrowing with combination of two dependent variables

Bug report

Probably since 2.1.40. See code snippet.

Code snippet that reproduces the problem

https://phpstan.org/r/d7b0e719-b39e-44d0-90a0-6f2079c25eae

Expected output

Line 33: same output as line 31 (the assertion on line 32 does not imply anything on $display_list)
Line 34: Dumped type: true

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No response

Simplified testcase:

Code snippet that reproduces the problem

https://phpstan.org/r/b28b8c9b-f4c8-40b2-ada3-c883650199a2

Expected output

Line 31: Dumped type: bool

Strangely, if I declare $list_of_ids as array<int> instead of list<int>, the bug disappears:

https://phpstan.org/r/bccbbab6-70a2-4355-9d2e-d37400cb0c1d

@claudepache

@claudepache After the latest push in 2.2.x, PHPStan now reports different result with your code snippet:

@@ @@
 26: Dumped type: false
 31: Dumped type: bool
-33: Dumped type: true
-34: Dumped type: *NEVER*
+33: Dumped type: bool
+34: Dumped type: true

Full report

Line	Error
26	`Dumped type: false`
31	`Dumped type: bool`
33	`Dumped type: bool`
34	`Dumped type: true`

@claudepache

@claudepache After the latest push in 2.2.x, PHPStan now reports different result with your code snippet:

@@ @@
-31: Dumped type: true
+31: Dumped type: bool

Full report

Line	Error
31	`Dumped type: bool`

Fixed: phpstan/phpstan-src@3993c52

That was fast! Thank you.

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incorrect type narrowing with combination of two dependent variables #14191

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incorrect type narrowing with combination of two dependent variables #14191

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Bug report

Code snippet that reproduces the problem

Expected output

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claudepache commented on Feb 23, 2026

Code snippet that reproduces the problem

Expected output

claudepache commented on Feb 24, 2026

phpstan-bot commented on Feb 24, 2026

phpstan-bot commented on Feb 24, 2026

ondrejmirtes commented on Feb 24, 2026

claudepache commented on Feb 24, 2026

github-actions commented on Mar 28, 2026

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