Better fix

Author: ondrejmirtes

src/Type/Php/InArrayFunctionTypeSpecifyingExtension.php

@@ -111,7 +111,8 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			|| (
 				$context->false()
 				&& count($arrayValueType->getFiniteTypes()) > 0
-				&& TypeCombinator::union(...$arrayValueType->getFiniteTypes())->equals($arrayValueType) // avoid edge-case of in_array(Enum, list<Enum>, true)
+				&& count($needleType->getFiniteTypes()) > 0
+				&& $arrayType->isIterableAtLeastOnce()->yes()
 			)
 		) {
 			$specifiedTypes = $this->typeSpecifier->create(
@@ -134,7 +135,7 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			$context->true()
 			|| (
 				$context->false()
-				&& count($needleType->getFiniteTypes()) > 0
+				&& count($needleType->getFiniteTypes()) === 1
 			)
 		) {
 			if ($context->true()) {

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

@@ -97,7 +97,7 @@ public function testNegative4(MyEnum $enum, array $array): void
 	{
 		if (!in_array($enum, $array, true)) {
 			assertType('MyEnum', $enum);
-			assertType('array<null>', $array);
+			assertType('array<MyEnum|null>', $array);
 		} else {
 			assertType('MyEnum', $enum);
 			assertType('non-empty-array<MyEnum|null>', $array);
@@ -117,7 +117,7 @@ public function testPositive(MyEnum $enum, array $list): void
 		}
 
 		assertType(MyEnum::class, $enum);
-		assertType('list<*NEVER*>&list<MyEnum>', $list);
+		assertType('list<MyEnum>', $list);
 	}
 
 	/** @param list<MyEnum> $list */