Fix broken edge-case, few more test cases

Author: janedbal

src/Type/Php/InArrayFunctionTypeSpecifyingExtension.php

@@ -15,9 +15,14 @@
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\ArrayType;
+use PHPStan\Type\Enum\EnumCaseObjectType;
 use PHPStan\Type\FunctionTypeSpecifyingExtension;
+use PHPStan\Type\IntersectionType;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeTraverser;
+use PHPStan\Type\UnionType;
 use function count;
 use function strtolower;
 
@@ -111,6 +116,7 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			|| (
 				$context->false()
 				&& count($arrayValueType->getFiniteTypes()) > 0
+				&& $this->isEnumCasesArray($arrayValueType) // avoid eliminating all enum cases in edge case like in_array(Enum, list<Enum>, true)
 			)
 		) {
 			$specifiedTypes = $this->typeSpecifier->create(
@@ -162,4 +168,23 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 		return $specifiedTypes;
 	}
 
+	private function isEnumCasesArray(Type $type): bool
+	{
+		$containsOnlyEnumCases = true;
+
+		TypeTraverser::map($type, static function (Type $type, callable $traverse) use (&$containsOnlyEnumCases): Type {
+			if ($type instanceof UnionType || $type instanceof IntersectionType) {
+				return $traverse($type);
+			}
+
+			if (!$type instanceof EnumCaseObjectType) {
+				$containsOnlyEnumCases = false;
+			}
+
+			return $type;
+		});
+
+		return $containsOnlyEnumCases;
+	}
+
 }

tests/PHPStan/Analyser/data/enum-in-array.php

@@ -1,22 +1,78 @@
 <?php
 
+use function PHPStan\Testing\assertType;
+
 enum MyEnum: string
 {
 
 	case A = 'a';
 	case B = 'b';
 	case C = 'c';
 
-	const SET1 = [self::A, self::B, self::C];
+	const SET_AB = [self::A, self::B];
+	const SET_C = [self::C];
+	const SET_ABC = [self::A, self::B, self::C];
+
+	public function test1(): void
+	{
+		foreach (MyEnum::cases() as $enum) {
+			if (in_array($enum, MyEnum::SET_AB, true)) {
+				assertType('MyEnum::A|MyEnum::B', $enum);
+			} elseif (in_array($enum, MyEnum::SET_C, true)) {
+				assertType('MyEnum::C', $enum);
+			} else {
+				assertType('*NEVER*', $enum);
+			}
+		}
+	}
+
+	public function test2(): void
+	{
+		foreach (MyEnum::cases() as $enum) {
+			if (in_array($enum, MyEnum::SET_ABC, true)) {
+				assertType('MyEnum::A|MyEnum::B|MyEnum::C', $enum);
+			} else {
+				assertType('*NEVER*', $enum);
+			}
+		}
+	}
+
+	public function test3(): void
+	{
+		foreach (MyEnum::cases() as $enum) {
+			if (in_array($enum, MyEnum::SET_C, true)) {
+				assertType('MyEnum::C', $enum);
+			} else {
+				assertType('MyEnum::A|MyEnum::B', $enum);
+			}
+		}
+	}
+	public function test4(): void
+	{
+		foreach ([MyEnum::C] as $enum) {
+			if (in_array($enum, MyEnum::SET_C, true)) {
+				assertType('MyEnum::C', $enum);
+			} else {
+				assertType('*NEVER*', $enum);
+			}
+		}
+	}
 
 }
 
+class InArrayEnum
+{
 
-foreach ([MyEnum::A, MyEnum::B, MyEnum::C] as $enum) {
+	/** @var list<MyEnum> */
+	private array $list = [];
 
-	if (in_array($enum, MyEnum::SET1, true)) {
+	public function doFoo(MyEnum $enum): void
+	{
+		if (in_array($enum, $this->list, true)) {
+			return;
+		}
 
-	} else {
-		\PHPStan\Testing\assertType('*NEVER*', $enum);
+		assertType(MyEnum::class, $enum);
 	}
+
 }