rand() values are ignored

[LauraTaylorUK]

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Bug report

PHPStan does not detect the parameter values passed to the rand() function. In my example snippet, you can see how it fails to understand that the input is always set, because the input values are either 1 or 2.

Code snippet that reproduces the problem

https://phpstan.org/r/0a3522ab-1db0-4fe5-96af-bec1b3a60ee1

Expected output

No error

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[mad-briller]

phpstan does understand how the parameters of rand affect it's output, and you can see that in this playground: https://phpstan.org/r/03208a7b-ec5d-4795-9f7c-3932dd793dcb

i've also added an example using the match statement that phpstan understands, because match is easier to make static guarantees about than multiple if/else statements.

analysing multiple if/else exhaustively would be quite a difficult thing to achieve and probably computationally expensive

[ondrejmirtes]

The problem isnn't about rand(), it's about exhaustiveness checking of int<1, 2> with === in the if statement.

[phpstan-bot]

@mad-briller After the latest push in 1.8.x, PHPStan now reports different result with your code snippet:

@@ @@
 10: Variable $input might not be defined.
 12: Variable $input might not be defined.
 19: Match arm is unreachable because previous comparison is always true.
-22: Dumped type: 'foo bar'|'invalid'|array{'foo bar'}
+22: Dumped type: 'foo bar'|array{'foo bar'}
 
 PHP 7.1 – 7.4 (2 errors)
 ==========

Full report

PHP 8.0 – 8.1 (6 errors)

Line	Error
3	Dumped type: int<1, 2>
10	Dumped type: mixed
10	Variable $input might not be defined.
12	Variable $input might not be defined.
19	Match arm is unreachable because previous comparison is always true.
22	`Dumped type: 'foo bar'

PHP 7.1 – 7.4 (2 errors)

Line	Error
17	Syntax error, unexpected T_DOUBLE_ARROW on line 17
18	Syntax error, unexpected ',' on line 18

[phpstan-bot]

@LauraTaylorUK After the latest push in 1.9.x, PHPStan now reports different result with your code snippet:

@@ @@
-9: Variable $input might not be defined.
+No errors

[phpstan-bot]

@mad-briller After the latest push in 1.9.x, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 8.0 – 8.1 (6 errors)
+PHP 8.0 – 8.1 (4 errors)
 ==========
 
  3: Dumped type: int<1, 2>
-10: Dumped type: mixed
-10: Variable $input might not be defined.
-12: Variable $input might not be defined.
+10: Dumped type: 'foo bar'|array{'foo bar'}
 19: Match arm is unreachable because previous comparison is always true.
-22: Dumped type: 'foo bar'|'invalid'|array{'foo bar'}
+22: Dumped type: 'foo bar'|array{'foo bar'}
 
 PHP 7.1 – 7.4 (2 errors)
 ==========

Full report

PHP 8.0 – 8.1 (4 errors)

Line	Error
3	Dumped type: int<1, 2>
10	`Dumped type: 'foo bar'
19	Match arm is unreachable because previous comparison is always true.
22	`Dumped type: 'foo bar'

PHP 7.1 – 7.4 (2 errors)

Line	Error
17	Syntax error, unexpected T_DOUBLE_ARROW on line 17
18	Syntax error, unexpected ',' on line 18

[phpstan-bot]

@LauraTaylorUK After the latest push in 1.10.x, PHPStan now reports different result with your code snippet:

@@ @@
-9: Variable $input might not be defined.
+No errors

[phpstan-bot]

@mad-briller After the latest push in 1.10.x, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 8.0 – 8.1 (6 errors)
+PHP 8.0 – 8.1 (4 errors)
 ==========
 
  3: Dumped type: int<1, 2>
-10: Dumped type: mixed
-10: Variable $input might not be defined.
-12: Variable $input might not be defined.
+10: Dumped type: 'foo bar'|array{'foo bar'}
 19: Match arm is unreachable because previous comparison is always true.
-22: Dumped type: 'foo bar'|'invalid'|array{'foo bar'}
+22: Dumped type: 'foo bar'|array{'foo bar'}
 
 PHP 7.1 – 7.4 (2 errors)
 ==========

Full report

PHP 8.0 – 8.1 (4 errors)

Line	Error
3	Dumped type: int<1, 2>
10	`Dumped type: 'foo bar'
19	Match arm is unreachable because previous comparison is always true.
22	`Dumped type: 'foo bar'

PHP 7.1 – 7.4 (2 errors)

Line	Error
17	Syntax error, unexpected T_DOUBLE_ARROW on line 17
18	Syntax error, unexpected ',' on line 18

[phpstan-bot]

@LauraTaylorUK After the latest push in 1.10.x, PHPStan now reports different result with your code snippet:

@@ @@
-9: Variable $input might not be defined.
+No errors

[phpstan-bot]

@mad-briller After the latest push in 1.10.x, PHPStan now reports different result with your code snippet:

@@ @@
-PHP 8.0 – 8.1 (6 errors)
+PHP 8.0 – 8.1 (4 errors)
 ==========
 
  3: Dumped type: int<1, 2>
-10: Dumped type: mixed
-10: Variable $input might not be defined.
-12: Variable $input might not be defined.
+10: Dumped type: 'foo bar'|array{'foo bar'}
 19: Match arm is unreachable because previous comparison is always true.
-22: Dumped type: 'foo bar'|'invalid'|array{'foo bar'}
+22: Dumped type: 'foo bar'|array{'foo bar'}
 
 PHP 7.1 – 7.4 (2 errors)
 ==========

Full report

PHP 8.0 – 8.1 (4 errors)

Line	Error
3	Dumped type: int<1, 2>
10	`Dumped type: 'foo bar'
19	Match arm is unreachable because previous comparison is always true.
22	`Dumped type: 'foo bar'

PHP 7.1 – 7.4 (2 errors)

Line	Error
17	Syntax error, unexpected T_DOUBLE_ARROW on line 17
18	Syntax error, unexpected ',' on line 18

[github-actions[bot]]

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