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psalm/docs/running_psalm/issues/ConflictingReferenceConstraint.md
2020-03-21 09:48:35 -04:00

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# ConflictingReferenceConstraint
Emitted when a by-ref variable is set in two different branches of an if to different types.
```php
<?php
class A {
/** @var int */
private $foo;
public function __construct(int &$foo) {
$this->foo = &$foo;
}
}
class B {
/** @var string */
private $bar;
public function __construct(string &$bar) {
$this->bar = &$bar;
}
}
if (rand(0, 1)) {
$v = 5;
$c = (new A($v)); // $v is constrained to an int
} else {
$v = "hello";
$c = (new B($v)); // $v is constrained to a string
}
$v = 8;
```
## Why this is bad
Psalm doesn't understand what the type of `$c` should be