Add comprehensive tests for duplicate declarations in traits (constants, properties, promoted properties, methods)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

tests/PHPStan/Rules/Classes/DuplicateTraitDeclarationRuleTest.php

@@ -23,6 +23,44 @@ public function testBug14250(): void
 				'Cannot redeclare method Bug14250\MyTrait::doSomething().',
 				11,
 			],
+			[
+				'Cannot redeclare constant Bug14250\TraitWithDuplicateConstants::CONST1.',
+				24,
+			],
+			[
+				'Cannot redeclare constant Bug14250\TraitWithDuplicateConstants::CONST2.',
+				26,
+			],
+			[
+				'Cannot redeclare property Bug14250\TraitWithDuplicateProperties::$prop1.',
+				41,
+			],
+			[
+				'Cannot redeclare property Bug14250\TraitWithDuplicateProperties::$prop2.',
+				44,
+			],
+			[
+				'Cannot redeclare method Bug14250\TraitWithDuplicateMethods::func1().',
+				59,
+			],
+			[
+				'Cannot redeclare method Bug14250\TraitWithDuplicateMethods::Func1().',
+				69,
+			],
+		]);
+	}
+
+	public function testDuplicatePromotedProperty(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-14250-promoted-properties.php'], [
+			[
+				'Cannot redeclare property Bug14250PromotedProperties\TraitWithDuplicatePromotedProperties::$foo.',
+				10,
+			],
+			[
+				'Cannot redeclare property Bug14250PromotedProperties\TraitWithDuplicatePromotedProperties::$bar.',
+				12,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Classes/data/bug-14250-promoted-properties.php

@@ -0,0 +1,22 @@
+<?php // lint >= 8.0
+
+namespace Bug14250PromotedProperties;
+
+trait TraitWithDuplicatePromotedProperties
+{
+	private $foo;
+
+	public function __construct(
+		private $foo,
+		private $bar,
+		private $bar
+	)
+	{
+
+	}
+}
+
+class Foo
+{
+	use TraitWithDuplicatePromotedProperties;
+}

tests/PHPStan/Rules/Classes/data/bug-14250.php

@@ -17,3 +17,59 @@ class Foo
 {
 	use MyTrait;
 }
+
+trait TraitWithDuplicateConstants
+{
+	public const CONST1 = 1;
+	public const CONST1 = 2;
+
+	public const CONST2 = 2, CONST2 = 1;
+
+	public const CONST3 = 1;
+}
+
+class Bar
+{
+	use TraitWithDuplicateConstants;
+}
+
+trait TraitWithDuplicateProperties
+{
+	/** @var int */
+	public $prop1;
+	/** @var int */
+	public $prop1;
+
+	/** @var int */
+	public $prop2, $prop2;
+
+	/** @var int */
+	public $prop3;
+}
+
+class Baz
+{
+	use TraitWithDuplicateProperties;
+}
+
+trait TraitWithDuplicateMethods
+{
+	public function func1(): void {}
+
+	public function func1(): int
+	{
+		return 1;
+	}
+
+	public function func2(): int
+	{
+		return 2;
+	}
+
+	public function Func1(): void {}
+}
+
+class Qux
+{
+	use TraitWithDuplicateMethods;
+}