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False/negative on nullable check #7905

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Closed
False/negative on nullable check#7905
Labels
feature-request
Milestone
Dependent types

Description

@olivernybroe
olivernybroe
opened on Sep 2, 2022

Bug report

$key = $data === null ? null : array_key_first($data);
$key === null ? null : $data[$key];

In the following example, we know that if $key is not null, then $data is not null, as key will be set to null if $data is null.
However phpstan does not figure this out.

Code snippet that reproduces the problem

https://phpstan.org/r/37fdd6a3-9478-43a1-92d1-e4c5abe6f1d0

Expected output

No nullable error

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Activity

  1. ondrejmirtes
    added
    feature-request
    on Sep 2, 2022
  2. ondrejmirtes
    added this to the Dependent types milestone on Sep 2, 2022

  3. phpstan-bot commented on Nov 4, 2023

    @phpstan-bot
    phpstan-bot
    on Nov 4, 2023
    Contributor

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

    @@ @@
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
 11: Offset string does not exist on array<string, string>|null.
 
-PHP 7.1 – 7.2 (3 errors)
+PHP 7.1 – 7.2 (2 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
-10: Function array_key_first not found.
-11: Offset mixed does not exist on array<string, string>|null.
+10: Function array_key_first not found.
    Full report

    PHP 8.0 – 8.2 (1 error)

    Line Error
    11 `Offset string does not exist on array<string, string>

    PHP 7.3 – 7.4 (2 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    11 `Offset string does not exist on array<string, string>

    PHP 7.1 – 7.2 (2 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    10 Function array_key_first not found.

  4. phpstan-bot commented on Sep 4, 2024

    @phpstan-bot
    phpstan-bot
    on Sep 4, 2024
    Contributor

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

    @@ @@
 
 11: Offset string does not exist on array<string, string>|null.
 
-PHP 7.3 – 7.4 (2 errors)
+PHP 7.3 – 7.4 (5 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
-11: Offset string does not exist on array<string, string>|null.
+ 8: Parameter $data of method HelloWorld::sayHello() has invalid type null.
+10: Parameter #1 $array of function array_key_first expects array, array<string, string>|null given.
+10: Strict comparison using === between array<string, string>|null and null will always evaluate to false.
+11: Cannot access offset mixed on array<string, string>|null.
 
-PHP 7.1 – 7.2 (3 errors)
+PHP 7.1 – 7.2 (5 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
+ 8: Parameter $data of method HelloWorld::sayHello() has invalid type null.
 10: Function array_key_first not found.
-11: Offset mixed does not exist on array<string, string>|null.
+10: Strict comparison using === between array<string, string>|null and null will always evaluate to false.
+11: Cannot access offset mixed on array<string, string>|null.
    Full report

    PHP 8.0 – 8.2 (1 error)

    Line Error
    11 `Offset string does not exist on array<string, string>

    PHP 7.3 – 7.4 (5 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    8 Parameter $data of method HelloWorld::sayHello() has invalid type null.
    10 `Parameter #1 $array of function array_key_first expects array, array<string, string>
    10 `Strict comparison using === between array<string, string>
    11 `Cannot access offset mixed on array<string, string>

    PHP 7.1 – 7.2 (5 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    8 Parameter $data of method HelloWorld::sayHello() has invalid type null.
    10 Function array_key_first not found.
    10 `Strict comparison using === between array<string, string>
    11 `Cannot access offset mixed on array<string, string>

  5. phpstan-bot commented on Sep 23, 2024

    @phpstan-bot
    phpstan-bot
    on Sep 23, 2024
    Contributor

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

    @@ @@
 PHP 8.0 – 8.2 (1 error)
 ==========
 
-11: Offset string does not exist on array<string, string>|null.
+11: Offset string might not exist on array<string, string>|null.
 
-PHP 7.3 – 7.4 (2 errors)
+PHP 7.3 – 7.4 (5 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
-11: Offset string does not exist on array<string, string>|null.
+ 8: Parameter $data of method HelloWorld::sayHello() has invalid type null.
+10: Parameter #1 $array of function array_key_first expects array, array<string, string>|null given.
+10: Strict comparison using === between array<string, string>|null and null will always evaluate to false.
+11: Cannot access offset mixed on array<string, string>|null.
 
-PHP 7.1 – 7.2 (3 errors)
+PHP 7.1 – 7.2 (5 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
+ 8: Parameter $data of method HelloWorld::sayHello() has invalid type null.
 10: Function array_key_first not found.
-11: Offset mixed does not exist on array<string, string>|null.
+10: Strict comparison using === between array<string, string>|null and null will always evaluate to false.
+11: Cannot access offset mixed on array<string, string>|null.
    Full report

    PHP 8.0 – 8.2 (1 error)

    Line Error
    11 `Offset string might not exist on array<string, string>

    PHP 7.3 – 7.4 (5 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    8 Parameter $data of method HelloWorld::sayHello() has invalid type null.
    10 `Parameter #1 $array of function array_key_first expects array, array<string, string>
    10 `Strict comparison using === between array<string, string>
    11 `Cannot access offset mixed on array<string, string>

    PHP 7.1 – 7.2 (5 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    8 Parameter $data of method HelloWorld::sayHello() has invalid type null.
    10 Function array_key_first not found.
    10 `Strict comparison using === between array<string, string>
    11 `Cannot access offset mixed on array<string, string>

  6. phpstan-bot commented on Feb 21, 2025

    @phpstan-bot
    phpstan-bot
    on Feb 21, 2025
    Contributor

    @olivernybroe After the latest push in 2.1.x, PHPStan now reports different result with your code snippet:

    @@ @@
 PHP 8.0 – 8.2 (1 error)
 ==========
 
-11: Offset string does not exist on array<string, string>|null.
+11: Offset string might not exist on array<string, string>|null.
 
-PHP 7.3 – 7.4 (2 errors)
+PHP 7.1 – 7.4 (5 errors)
 ==========
 
  8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
-11: Offset string does not exist on array<string, string>|null.
-
-PHP 7.1 – 7.2 (3 errors)
-==========
-
- 8: Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
-10: Function array_key_first not found.
-11: Offset mixed does not exist on array<string, string>|null.
+ 8: Parameter $data of method HelloWorld::sayHello() has invalid type null.
+10: Parameter #1 $array of function array_key_first expects array, array<string, string>|null given.
+10: Strict comparison using === between array<string, string>|null and null will always evaluate to false.
+11: Cannot access offset mixed on array<string, string>|null.
    Full report

    PHP 8.0 – 8.2 (1 error)

    Line Error
    11 `Offset string might not exist on array<string, string>

    PHP 7.1 – 7.4 (5 errors)

    Line Error
    8 Method HelloWorld::sayHello() uses native union types but they're supported only on PHP 8.0 and later.
    8 Parameter $data of method HelloWorld::sayHello() has invalid type null.
    10 `Parameter #1 $array of function array_key_first expects array, array<string, string>
    10 `Strict comparison using === between array<string, string>
    11 `Cannot access offset mixed on array<string, string>

  7. phpstan-bot commented on Sep 11, 2026

    @phpstan-bot
    phpstan-bot
    on Sep 11, 2026
    Contributor

    Closed via merging phpstan/phpstan-src#6381

  8. phpstan-bot
    closed this as completedon Sep 11, 2026

  9. github-actions commented on Oct 13, 2026

    @github-actions
    github-actionsBot
    on Oct 13, 2026 – with 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.

  10. github-actions
    locked as resolved and limited conversation to collaborators on Oct 13, 2026
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