Regression test

Closes phpstan/phpstan#6856

Author: ondrejmirtes

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -119,6 +119,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3269.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/assign-nested-arrays.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3276.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Methods/data/bug-6856.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/shadowed-trait-methods.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/const-in-functions.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/const-in-functions-namespaced.php');

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -934,4 +934,9 @@ public function testLists(): void
 		]);
 	}
 
+	public function testBug6856(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-6856.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-6856.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace Bug6856;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T of object
+ */
+trait TraitA {
+	/**
+	 * @return T
+	 */
+	public function a(): object {
+		return new ClassB();
+	}
+
+	/**
+	 * @return T
+	 */
+	public function test(): object {
+		return new ClassB();
+	}
+}
+
+class ClassA {
+	/**
+	 * @phpstan-use TraitA<ClassB>
+	 */
+	use TraitA {
+		a as renamed;
+	}
+
+	public function a(): ClassB {
+		return $this->renamed();
+	}
+
+	public function b(): ClassB {
+		return $this->test();
+	}
+}
+
+class ClassB {
+	// empty
+}
+
+function (ClassA $a): void {
+	assertType(ClassB::class, $a->a());
+	assertType(ClassB::class, $a->renamed());
+	assertType(ClassB::class, $a->test());
+	assertType(ClassB::class, $a->b());
+};