Bug report

1. Create a readonly promoted property.
2. Add a trait that uses that property.
3. Call trait method from the constructor.

<?php

trait TestTrait {
	public function foo(): void
	{
		$this->callee->foo();
	}
}

class TestCallee {
	public function foo(): void
	{
		echo "FOO\n";
	}
}

class TestCaller {
	use TestTrait;

	public function __construct(private readonly TestCallee $callee)
	{
		$this->foo();
	}
}

new TestCaller(new TestCallee());

Line 6: Access to an uninitialized readonly property TestCaller::$callee.

https://phpstan.org/r/c2519e6b-5e12-4a77-97ff-6c81de2b7dfa

Expected output

No errors. According to the RFC:

The forwarding property assignments occur at the start of the constructor. As such, it is possible to access both the parameter and the property in the constructor […]

In addition, if the trait is defined in a separate file (as would usually be the case), an additional issue manifests that adds to the confusion: the error is reported in the file of the class, but line number corresponds to the file of the trait.

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