Make ReflectionEnum generic

conf/config.neon

@@ -35,6 +35,7 @@ parameters:
 			- InfiniteIterator
 			- CachingIterator
 			- RegexIterator
+			- ReflectionEnum
 		explicitMixedInUnknownGenericNew: false
 		explicitMixedForGlobalVariables: false
 		explicitMixedViaIsArray: false

stubs/ReflectionClass.stub

@@ -48,3 +48,23 @@ class ReflectionClass
     {
     }
 }
+
+/**
+ * @template-covariant T of UnitEnum
+ * @extends ReflectionClass<T>
+ */
+class ReflectionEnum extends ReflectionClass
+{
+
+	/**
+	 * @return (T is BackedEnum ? ReflectionEnumBackedCase[] : ReflectionEnumUnitCase[])
+	 */
+	public function getCases(): array {}
+
+	/**
+	 * @return (T is BackedEnum ? ReflectionEnumBackedCase : ReflectionEnumUnitCase)
+	 * @throws ReflectionException If no found single reflection object for the corresponding case
+	 */
+	public function getCase(string $name): ReflectionEnumUnitCase {}
+
+}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -240,6 +240,7 @@ public function dataFileAsserts(): iterable
 
 		if (PHP_VERSION_ID >= 80100) {
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9734.php');
+			yield from $this->gatherAssertTypes(__DIR__ . '/data/enum-reflection.php');
 		}
 
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/match-expr.php');

tests/PHPStan/Analyser/data/enum-reflection.php

@@ -0,0 +1,43 @@
+<?php // lint >= 8.1
+
+namespace EnumReflection;
+
+use ReflectionEnum;
+use ReflectionEnumBackedCase;
+use ReflectionEnumUnitCase;
+use function PHPStan\Testing\assertType;
+
+enum Foo: int
+{
+
+	case FOO = 1;
+	case BAR = 2;
+
+	public function doFoo(): void
+	{
+		$r = new ReflectionEnum(self::class);
+		foreach ($r->getCases() as $case) {
+			assertType(ReflectionEnumBackedCase::class, $case);
+		}
+
+		assertType(ReflectionEnumBackedCase::class, $r->getCase('FOO'));
+	}
+
+}
+
+enum Bar
+{
+
+	case FOO;
+	case BAR;
+
+	public function doFoo(): void
+	{
+		$r = new ReflectionEnum(self::class);
+		foreach ($r->getCases() as $case) {
+			assertType(ReflectionEnumUnitCase::class, $case);
+		}
+		assertType(ReflectionEnumUnitCase::class, $r->getCase('FOO'));
+	}
+
+}