Make value-of<...> lazier

src/PhpDoc/TypeNodeResolver.php

@@ -696,22 +696,8 @@ static function (string $variance): TemplateTypeVariance {
 			return new ErrorType();
 		} elseif ($mainTypeName === 'value-of') {
 			if (count($genericTypes) === 1) { // value-of<ValueType>
-				$genericType = $genericTypes[0];
-				if ($genericType->isEnum()->yes()) {
-					$valueTypes = [];
-					foreach ($genericType->getEnumCases() as $enumCase) {
-						$valueType = $enumCase->getBackingValueType();
-						if ($valueType === null) {
-							continue;
-						}
-
-						$valueTypes[] = $valueType;
-					}
-
-					return TypeCombinator::union(...$valueTypes);
-				}
+				$type = new ValueOfType($genericTypes[0]);
 
-				$type = new ValueOfType($genericType);
 				return $type->isResolvable() ? $type->resolve() : $type;
 			}
 

src/Type/ValueOfType.php

@@ -49,6 +49,20 @@ public function isResolvable(): bool
 
 	protected function getResult(): Type
 	{
+		if ($this->type->isEnum()->yes()) {
+			$valueTypes = [];
+			foreach ($this->type->getEnumCases() as $enumCase) {
+				$valueType = $enumCase->getBackingValueType();
+				if ($valueType === null) {
+					continue;
+				}
+
+				$valueTypes[] = $valueType;
+			}
+
+			return TypeCombinator::union(...$valueTypes);
+		}
+
 		return $this->type->getIterableValueType();
 	}
 

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -334,6 +334,11 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-sum.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-plus.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4573.php');
+
+		if (PHP_VERSION_ID >= 80100) {
+			yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-9881.php');
+		}
+
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4577.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4579.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3321.php');

tests/PHPStan/Analyser/data/bug-9881.php

@@ -0,0 +1,27 @@
+<?php // lint >= 8.1
+
+namespace Bug9881;
+
+use BackedEnum;
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	/**
+	 * @template B of BackedEnum
+	 * @param B[] $enums
+	 * @return value-of<B>[]
+	 */
+	public static function arrayEnumToStrings(array $enums): array
+	{
+		return array_map(static fn (BackedEnum $code): string|int => $code->value, $enums);
+	}
+}
+
+enum Test: string {
+	case DA = 'da';
+}
+
+function (Test ...$da): void {
+	assertType('array<\'da\'>', HelloWorld::arrayEnumToStrings($da));
+};