Fix return type of array_reverse() with optional keys

Author: herndlm

src/Type/Constant/ConstantArrayType.php

@@ -51,7 +51,6 @@
 use function array_merge;
 use function array_pop;
 use function array_push;
-use function array_reverse;
 use function array_slice;
 use function array_unique;
 use function array_values;
@@ -892,14 +891,16 @@ public function popArray(): Type
 
 	public function reverseArray(TrinaryLogic $preserveKeys): Type
 	{
-		$keyTypesReversed = array_reverse($this->keyTypes, true);
-		$keyTypes = array_values($keyTypesReversed);
-		$keyTypesReversedKeys = array_keys($keyTypesReversed);
-		$optionalKeys = array_map(static fn (int $optionalKey): int => $keyTypesReversedKeys[$optionalKey], $this->optionalKeys);
+		$builder = ConstantArrayTypeBuilder::createEmpty();
 
-		$reversed = new self($keyTypes, array_reverse($this->valueTypes), $this->nextAutoIndexes, $optionalKeys, TrinaryLogic::createNo());
+		for ($i = count($this->keyTypes) - 1; $i >= 0; $i--) {
+			$offsetType = $preserveKeys->yes() || $this->keyTypes[$i]->isInteger()->no()
+				? $this->keyTypes[$i]
+				: null;
+			$builder->setOffsetValueType($offsetType, $this->valueTypes[$i], $this->isOptionalKey($i));
+		}
 
-		return $preserveKeys->yes() ? $reversed : $reversed->reindex();
+		return $builder->getArray();
 	}
 
 	public function searchArray(Type $needleType): Type

tests/PHPStan/Analyser/nsrt/array-reverse.php

@@ -22,8 +22,9 @@ public function normalArrays(array $a, array $b): void
 	/**
 	 * @param array{a: 'foo', b: 'bar', c?: 'baz'} $a
 	 * @param array{17: 'foo', 19: 'bar'}|array{foo: 17, bar: 19} $b
+	 * @param array{0: 'A', 1?: 'B', 2?: 'C'} $c
 	 */
-	public function constantArrays(array $a, array $b): void
+	public function constantArrays(array $a, array $b, array $c): void
 	{
 		assertType('array{}', array_reverse([]));
 		assertType('array{}', array_reverse([], true));
@@ -45,6 +46,9 @@ public function constantArrays(array $a, array $b): void
 
 		assertType('array{\'bar\', \'foo\'}|array{bar: 19, foo: 17}', array_reverse($b));
 		assertType('array{19: \'bar\', 17: \'foo\'}|array{bar: 19, foo: 17}', array_reverse($b, true));
+
+		assertType("array{0: 'A'|'B'|'C', 1?: 'A'|'B', 2?: 'A'}", array_reverse($c));
+		assertType("array{2?: 'C', 1?: 'B', 0: 'A'}", array_reverse($c, true));
 	}
 
 	/**

tests/PHPStan/Rules/Functions/ReturnTypeRuleTest.php

@@ -297,4 +297,11 @@ public function testBug8881(): void
 		$this->analyse([__DIR__ . '/data/bug-8881.php'], []);
 	}
 
+	public function testBug11549(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->checkNullables = true;
+		$this->analyse([__DIR__ . '/data/bug-11549.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Functions/data/bug-11549.php

@@ -0,0 +1,13 @@
+<?php
+declare(strict_types = 1);
+
+namespace Bug11549;
+
+/**
+ * @param  array{0: string, 1?: string} $a
+ * @return array{0: string, 1?: string}
+ */
+function rrr(array $a): array
+{
+	return array_reverse($a);
+}