Array shape with optional keys might be a list

Author: ondrejmirtes

src/Type/Constant/ConstantArrayTypeBuilder.php

@@ -163,7 +163,11 @@ public function setOffsetValueType(?Type $offsetType, Type $valueType, bool $opt
 					$min = min($this->nextAutoIndexes);
 					$max = max($this->nextAutoIndexes);
 					if ($offsetType->getValue() > $min) {
-						$this->isList = TrinaryLogic::createNo();
+						if ($offsetType->getValue() <= $max) {
+							$this->isList = $this->isList->and(TrinaryLogic::createMaybe());
+						} else {
+							$this->isList = TrinaryLogic::createNo();
+						}
 					}
 					if ($offsetType->getValue() >= $max) {
 						/** @var int|float $newAutoIndex */

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -161,6 +161,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/../Rules/Comparison/data/bug-2550.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-2899.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/preg_split.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-shape-list-optional.php');
 
 		if (PHP_VERSION_ID < 80000) {
 			yield from $this->gatherAssertTypes(__DIR__ . '/data/bcmath-dynamic-return-php7.php');

tests/PHPStan/Analyser/data/array-shape-list-optional.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace ArrayShapeListOptional;
+
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+
+	/**
+	 * @param list{0: string, 1: int, 2?: string, 3?: string} $valid1
+	 * @param list{0: string, 1: int, 2?: string, 4?: string} $invalid1
+	 * @param list{0: string, 1: int, 2?: string, foo?: string} $invalid2
+	 */
+	public function doFoo(
+		$valid1,
+		$invalid1,
+		$invalid2
+	): void
+	{
+		assertType('array{0: string, 1: int, 2?: string, 3?: string}&list', $valid1);
+		assertType('*NEVER*', $invalid1);
+		assertType('*NEVER*', $invalid2);
+	}
+
+}

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -924,12 +924,12 @@ public function testLists(): void
 			[
 				"Method ReturnList\Foo::getList1() should return list<string> but returns array{0?: 'foo', 1?: 'bar'}.",
 				10,
-				"array{0?: 'foo', 1?: 'bar'} is not a list.",
+				"array{0?: 'foo', 1?: 'bar'} might not be a list.",
 			],
 			[
 				"Method ReturnList\Foo::getList2() should return list<string> but returns array{0?: 'foo', 1?: 'bar'}.",
 				19,
-				"array{0?: 'foo', 1?: 'bar'} is not a list.",
+				"array{0?: 'foo', 1?: 'bar'} might not be a list.",
 			],
 		]);
 	}