report trait access to unititialized property in the trait instead of class

src/Node/ClassPropertiesNode.php

@@ -92,7 +92,7 @@ public function getClassReflection(): ClassReflection
 	/**
 	 * @param string[] $constructors
 	 * @param ReadWritePropertiesExtension[]|null $extensions
-	 * @return array{array<string, ClassPropertyNode>, array<array{string, int, ClassPropertyNode}>, array<array{string, int, ClassPropertyNode}>}
+	 * @return array{array<string, ClassPropertyNode>, array<array{string, int, ClassPropertyNode, string}>, array<array{string, int, ClassPropertyNode}>}
 	 */
 	public function getUninitializedProperties(
 		Scope $scope,
@@ -212,6 +212,7 @@ public function getUninitializedProperties(
 						$propertyName,
 						$fetch->getLine(),
 						$originalProperties[$propertyName],
+						$usageScope->getFileDescription(),
 					];
 				}
 			}

src/Rules/Properties/MissingReadOnlyByPhpDocPropertyAssignRule.php

@@ -44,15 +44,15 @@ public function processNode(Node $node, Scope $scope): array
 			))->line($propertyNode->getLine())->build();
 		}
 
-		foreach ($prematureAccess as [$propertyName, $line, $propertyNode]) {
+		foreach ($prematureAccess as [$propertyName, $line, $propertyNode, $file]) {
 			if (!$propertyNode->isReadOnlyByPhpDoc() || $propertyNode->isReadOnly()) {
 				continue;
 			}
 			$errors[] = RuleErrorBuilder::message(sprintf(
 				'Access to an uninitialized @readonly property %s::$%s.',
 				$classReflection->getDisplayName(),
 				$propertyName,
-			))->line($line)->build();
+			))->line($line)->file($file)->build();
 		}
 
 		foreach ($additionalAssigns as [$propertyName, $line, $propertyNode]) {

src/Rules/Properties/MissingReadOnlyPropertyAssignRule.php

@@ -44,15 +44,15 @@ public function processNode(Node $node, Scope $scope): array
 			))->line($propertyNode->getLine())->build();
 		}
 
-		foreach ($prematureAccess as [$propertyName, $line, $propertyNode]) {
+		foreach ($prematureAccess as [$propertyName, $line, $propertyNode, $file]) {
 			if (!$propertyNode->isReadOnly()) {
 				continue;
 			}
 			$errors[] = RuleErrorBuilder::message(sprintf(
 				'Access to an uninitialized readonly property %s::$%s.',
 				$classReflection->getDisplayName(),
 				$propertyName,
-			))->line($line)->build();
+			))->line($line)->file($file)->build();
 		}
 
 		foreach ($additionalAssigns as [$propertyName, $line, $propertyNode]) {

src/Rules/Properties/UninitializedPropertyRule.php

@@ -44,15 +44,15 @@ public function processNode(Node $node, Scope $scope): array
 			))->line($propertyNode->getLine())->build();
 		}
 
-		foreach ($prematureAccess as [$propertyName, $line, $propertyNode]) {
+		foreach ($prematureAccess as [$propertyName, $line, $propertyNode, $file]) {
 			if ($propertyNode->isReadOnly() || $propertyNode->isReadOnlyByPhpDoc()) {
 				continue;
 			}
 			$errors[] = RuleErrorBuilder::message(sprintf(
 				'Access to an uninitialized property %s::$%s.',
 				$classReflection->getDisplayName(),
 				$propertyName,
-			))->line($line)->build();
+			))->line($line)->file($file)->build();
 		}
 
 		return $errors;

tests/PHPStan/Analyser/AnalyserTraitsIntegrationTest.php

@@ -5,7 +5,11 @@
 use PHPStan\File\FileHelper;
 use PHPStan\Testing\PHPStanTestCase;
 use function array_map;
+use function array_merge;
+use function array_unique;
 use function sprintf;
+use function usort;
+use const PHP_VERSION_ID;
 
 class AnalyserTraitsIntegrationTest extends PHPStanTestCase
 {
@@ -165,6 +169,36 @@ public function testMissingReturnInAbstractTraitMethod(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testUnititializedReadonlyPropertyAccessedInTrait(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped();
+		}
+
+		$errors = $this->runAnalyse([
+			__DIR__ . '/traits/uninitializedProperty/FooClass.php',
+			__DIR__ . '/traits/uninitializedProperty/FooTrait.php',
+		]);
+		$this->assertCount(3, $errors);
+		usort($errors, static fn (Error $a, Error $b) => $a->getLine() <=> $b->getLine());
+		$expectedFile = sprintf('%s (in context of class TraitsUnititializedProperty\FooClass)', $this->fileHelper->normalizePath(__DIR__ . '/traits/uninitializedProperty/FooTrait.php'));
+
+		$error = $errors[0];
+		$this->assertSame('Access to an uninitialized readonly property TraitsUnititializedProperty\FooClass::$x.', $error->getMessage());
+		$this->assertSame(15, $error->getLine());
+		$this->assertSame($expectedFile, $error->getFile());
+
+		$error = $errors[1];
+		$this->assertSame('Access to an uninitialized @readonly property TraitsUnititializedProperty\FooClass::$y.', $error->getMessage());
+		$this->assertSame(16, $error->getLine());
+		$this->assertSame($expectedFile, $error->getFile());
+
+		$error = $errors[2];
+		$this->assertSame('Access to an uninitialized property TraitsUnititializedProperty\FooClass::$z.', $error->getMessage());
+		$this->assertSame(17, $error->getLine());
+		$this->assertSame($expectedFile, $error->getFile());
+	}
+
 	/**
 	 * @param string[] $files
 	 * @return Error[]
@@ -178,4 +212,17 @@ private function runAnalyse(array $files): array
 		return $analyser->analyse($files)->getErrors();
 	}
 
+	public static function getAdditionalConfigFiles(): array
+	{
+		return array_unique(
+			array_merge(
+				parent::getAdditionalConfigFiles(),
+				[
+					__DIR__ . '/../../../conf/bleedingEdge.neon',
+					__DIR__ . '/traits-integration.neon',
+				],
+			),
+		);
+	}
+
 }

tests/PHPStan/Analyser/traits-integration.neon

@@ -0,0 +1,2 @@
+parameters:
+    checkUninitializedProperties: true

tests/PHPStan/Analyser/traits/uninitializedProperty/FooClass.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace TraitsUnititializedProperty;
+
+class FooClass
+{
+	use FooTrait;
+
+	public function __construct()
+	{
+		$this->foo();
+		$this->x = 5;
+		$this->y = 5;
+		$this->z = 5;
+	}
+}

tests/PHPStan/Analyser/traits/uninitializedProperty/FooTrait.php

@@ -0,0 +1,19 @@
+<?php // lint >= 8.1
+
+namespace TraitsUnititializedProperty;
+
+trait FooTrait
+{
+	protected readonly int $x;
+
+	/** @readonly */
+	protected int $y;
+	protected int $z;
+
+	public function foo(): void
+	{
+		echo $this->x;
+		echo $this->y;
+		echo $this->z;
+	}
+}