Fix phpstan/phpstan#10690: skip unused private constant check for trait constants

- Added ClassConstant wrapper class (similar to ClassMethod) that tracks isDeclaredInTrait
- Updated ClassStatementsGatherer to wrap ClassConst nodes with trait context
- Updated ClassConstantsNode with getClassConstants() method preserving backward compatibility
- UnusedPrivateConstantRule now skips constants declared in traits
- Added regression test in tests/PHPStan/Rules/DeadCode/data/bug-10690.php

Author: github-actions[bot]

src/Node/ClassConstant.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Node;
+
+use PhpParser\Node\Stmt\ClassConst;
+
+/**
+ * @api
+ */
+final class ClassConstant
+{
+
+	public function __construct(
+		private ClassConst $node,
+		private bool $isDeclaredInTrait,
+	)
+	{
+	}
+
+	public function getNode(): ClassConst
+	{
+		return $this->node;
+	}
+
+	public function isDeclaredInTrait(): bool
+	{
+		return $this->isDeclaredInTrait;
+	}
+
+}

src/Node/ClassConstantsNode.php

@@ -8,6 +8,7 @@
 use PhpParser\NodeAbstract;
 use PHPStan\Node\Constant\ClassConstantFetch;
 use PHPStan\Reflection\ClassReflection;
+use function array_map;
 
 /**
  * @api
@@ -16,7 +17,7 @@ final class ClassConstantsNode extends NodeAbstract implements VirtualNode
 {
 
 	/**
-	 * @param ClassConst[] $constants
+	 * @param ClassConstant[] $constants
 	 * @param ClassConstantFetch[] $fetches
 	 */
 	public function __construct(private ClassLike $class, private array $constants, private array $fetches, private ClassReflection $classReflection)
@@ -33,6 +34,14 @@ public function getClass(): ClassLike
 	 * @return ClassConst[]
 	 */
 	public function getConstants(): array
+	{
+		return array_map(static fn (ClassConstant $constant) => $constant->getNode(), $this->constants);
+	}
+
+	/**
+	 * @return ClassConstant[]
+	 */
+	public function getClassConstants(): array
 	{
 		return $this->constants;
 	}

src/Node/ClassStatementsGatherer.php

@@ -47,7 +47,7 @@ final class ClassStatementsGatherer
 	/** @var array<int, PropertyWrite|PropertyRead> */
 	private array $propertyUsages = [];
 
-	/** @var Node\Stmt\ClassConst[] */
+	/** @var ClassConstant[] */
 	private array $constants = [];
 
 	/** @var ClassConstantFetch[] */
@@ -103,7 +103,7 @@ public function getPropertyUsages(): array
 	}
 
 	/**
-	 * @return Node\Stmt\ClassConst[]
+	 * @return ClassConstant[]
 	 */
 	public function getConstants(): array
 	{
@@ -165,7 +165,7 @@ private function gatherNodes(Node $node, Scope $scope): void
 			return;
 		}
 		if ($node instanceof Node\Stmt\ClassConst) {
-			$this->constants[] = $node;
+			$this->constants[] = new ClassConstant($node, $scope->isInTrait());
 			return;
 		}
 		if ($node instanceof MethodCall || $node instanceof StaticCall) {

src/Rules/DeadCode/UnusedPrivateConstantRule.php

@@ -38,11 +38,16 @@ public function processNode(Node $node, Scope $scope): array
 		$classType = new ObjectType($classReflection->getName(), classReflection: $classReflection);
 
 		$constants = [];
-		foreach ($node->getConstants() as $constant) {
+		foreach ($node->getClassConstants() as $classConstant) {
+			$constant = $classConstant->getNode();
 			if (!$constant->isPrivate()) {
 				continue;
 			}
 
+			if ($classConstant->isDeclaredInTrait()) {
+				continue;
+			}
+
 			foreach ($constant->consts as $const) {
 				$constantName = $const->name->toString();
 

tests/PHPStan/Rules/DeadCode/UnusedPrivateConstantRuleTest.php

@@ -88,6 +88,12 @@ public function testBug9765(): void
 		$this->analyse([__DIR__ . '/data/bug-9765.php'], []);
 	}
 
+	#[RequiresPhp('>= 8.2')]
+	public function testBug10690(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10690.php'], []);
+	}
+
 	#[RequiresPhp('>= 8.3')]
 	public function testDynamicConstantFetch(): void
 	{

tests/PHPStan/Rules/DeadCode/data/bug-10690.php

@@ -0,0 +1,29 @@
+<?php // lint >= 8.2
+
+declare(strict_types = 1);
+
+namespace Bug10690;
+
+trait MyTrait
+{
+	private const AAA='aaa';
+	private const BBB='bbb';
+}
+
+final class First
+{
+	use MyTrait;
+
+	function a(): string {
+		return self::AAA.self::BBB;
+	}
+}
+
+final class SecondConsumer
+{
+	use MyTrait;
+
+	function b(): string {
+		return self::AAA;
+	}
+}