Fix list consideration with union of scalar as offset

Author: VincentLanglet

src/Type/Constant/ConstantArrayTypeBuilder.php

@@ -199,8 +199,6 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $opt
 				return;
 			}
 
-			$this->isList = TrinaryLogic::createNo();
-
 			$scalarTypes = $offsetType->getConstantScalarTypes();
 			if (count($scalarTypes) === 0) {
 				$integerRanges = TypeUtils::getIntegerRanges($offsetType);
@@ -257,6 +255,8 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $opt
 					return;
 				}
 			}
+
+			$this->isList = TrinaryLogic::createNo();
 		}
 
 		if ($offsetType === null) {

tests/PHPStan/Analyser/nsrt/array-is-list-offset.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace ArrayIsListUnset;
+
+use function PHPStan\Testing\assertType;
+
+class Foo {
+	/**
+	 * @param array{bool, bool, bool} $array
+	 * @param int<0, 1> $key
+	 */
+	public function test(array $array, int $key) {
+		assertType('int<0, 1>', $key);
+		assertType('true', array_is_list($array));
+
+		$array[$key] = false;
+		assertType('true', array_is_list($array));
+	}
+}