False positive: offset 1 on array does not exist

[EreMaijala]

Bug report

PHPStan versions starting with 1.10.11 reports the error Offset 1 on array<0, array{name: string, lines: non-empty-array<int<0, max>, string>}> in isset() does not exist. for the example code snippet. Version 1.10.10 does not suffer from this issue.

Code snippet that reproduces the problem

https://phpstan.org/r/fca2eeda-2636-47d5-9ba5-4c501ec5e9b5

Expected output

No errors reported.

Did PHPStan help you today? Did it make you happy in any way?

It sure did! It caught a couple of other edge cases that would have slipped through otherwise.

[phpstan-bot]

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

@@ @@
 
 31: Offset 1 on array<0, array{name: string, lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.
 
-PHP 7.2 – 7.4 (3 errors)
+PHP 7.2 – 7.4 (1 error)
 ==========
 
-14: Function str_starts_with not found.
-15: Function str_ends_with not found.
 31: Offset 1 on array<0, array{name: (string|false), lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.

Full report

PHP 8.0 – 8.2 (1 error)

Line	Error
31	Offset 1 on array<0, array{name: string, lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.

PHP 7.2 – 7.4 (1 error)

Line	Error
31	`Offset 1 on array<0, array{name: (string

[rabol]

I get more or less the same error on this:

if (count($spanContents) == 4) {
    $servings = (int) $spanContents[2];
}

my error is :

 Offset 2 does not exist on non-empty-array<0, string>.  

[staabm]

@rabol please provide a snippet on phpstan.org/try which shows your case, otherwise we cannot judge whether its a bug or not.

[rabol]

https://phpstan.org/r/d175b0b8-ce2e-4fd0-8a85-cce71467ce22

[staabm]

@rabol the by-reference stuff is hard to figure out for PHPStan. you could give it a /** @var list<string> */ hint and the error goes away:

https://phpstan.org/r/eb036b60-2ae9-4600-a41d-6e53e9d2458a

[rabol]

adding /** @var list<string> */ does not work

[rabol]

sorry, my mistake /** @var list<string> $spanContents */ works

[phpstan-bot]

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

@@ @@
 PHP 8.0 – 8.2 (1 error)
 ==========
 
-31: Offset 1 on array<0, array{name: string, lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.
+31: Offset 1 on array<0, array{name: string, lines: non-empty-list<string>}>&list in isset() does not exist.
 
-PHP 7.2 – 7.4 (3 errors)
+PHP 7.2 – 7.4 (1 error)
 ==========
 
-14: Function str_starts_with not found.
-15: Function str_ends_with not found.
-31: Offset 1 on array<0, array{name: (string|false), lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.
+31: Offset 1 on array<0, array{name: (string|false), lines: non-empty-list<string>}>&list in isset() does not exist.

Full report

PHP 8.0 – 8.2 (1 error)

Line	Error
31	Offset 1 on array<0, array{name: string, lines: non-empty-list<string>}>&list in isset() does not exist.

PHP 7.2 – 7.4 (1 error)

Line	Error
31	`Offset 1 on array<0, array{name: (string

[phpstan-bot]

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

@@ @@
 10: Call to method filter() on an unknown class Response.
 10: Parameter $span of anonymous function has invalid type Crawler.
 12: Call to method text() on an unknown class Crawler.
-15: Offset 2 does not exist on non-empty-array<0, mixed>.
+15: Offset 2 does not exist on non-empty-array<0, mixed>&list.

Full report

Line	Error
5	Parameter $response of method HelloWorld::sayHello() has invalid type Response.
10	Call to method filter() on an unknown class Response.
10	Parameter $span of anonymous function has invalid type Crawler.
12	Call to method text() on an unknown class Crawler.
15	Offset 2 does not exist on non-empty-array<0, mixed>&list.

[phpstan-bot]

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

@@ @@
 PHP 8.0 – 8.2 (1 error)
 ==========
 
-31: Offset 1 on array<0, array{name: string, lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.
+31: Offset 1 on list<array{name: string, lines: non-empty-list<string>}> in isset() does not exist.
 
-PHP 7.2 – 7.4 (3 errors)
+PHP 7.2 – 7.4 (1 error)
 ==========
 
-14: Function str_starts_with not found.
-15: Function str_ends_with not found.
-31: Offset 1 on array<0, array{name: (string|false), lines: non-empty-array<int<0, max>, string>}> in isset() does not exist.
+31: Offset 1 on list<array{name: (string|false), lines: non-empty-list<string>}> in isset() does not exist.

Full report

PHP 8.0 – 8.2 (1 error)

Line	Error
31	Offset 1 on list<array{name: string, lines: non-empty-list<string>}> in isset() does not exist.

PHP 7.2 – 7.4 (1 error)

Line	Error
31	`Offset 1 on list<array{name: (string