Fix array_merge with numeric keys

Author: herndlm

src/Type/Php/ArrayMergeFunctionDynamicReturnTypeExtension.php

@@ -11,6 +11,7 @@
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
+use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
@@ -64,7 +65,7 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 					$isOptional = in_array($k, $optionalKeys, true);
 
 					$newArrayBuilder->setOffsetValueType(
-						$keyType,
+						$keyType instanceof ConstantIntegerType ? null : $keyType,
 						$valueTypes[$k],
 						$isOptional,
 					);

tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php

@@ -4727,7 +4727,7 @@ public function dataArrayFunctions(): array
 				'array_values($generalStringKeys)',
 			],
 			[
-				'array{foo: stdClass, 1: stdClass}',
+				'array{foo: stdClass, 0: stdClass}',
 				'array_merge($stringOrIntegerKeys)',
 			],
 			[
@@ -4743,15 +4743,15 @@ public function dataArrayFunctions(): array
 				'array_merge($stringOrIntegerKeys, $generalStringKeys)',
 			],
 			[
-				'array{foo: stdClass, bar: stdClass, 1: stdClass}',
+				'array{foo: stdClass, bar: stdClass, 0: stdClass}',
 				'array_merge($stringKeys, $stringOrIntegerKeys)',
 			],
 			[
-				"array{foo: 'foo', 1: stdClass, bar: stdClass}",
+				"array{foo: 'foo', 0: stdClass, bar: stdClass}",
 				'array_merge($stringOrIntegerKeys, $stringKeys)',
 			],
 			[
-				"array{color: 'green', 0: 'a', 1: 'b', shape: 'trapezoid', 2: 4}",
+				"array{color: 'green', 0: 2, 1: 4, 2: 'a', 3: 'b', shape: 'trapezoid', 4: 4}",
 				'array_merge(array("color" => "red", 2, 4), array("a", "b", "color" => "green", "shape" => "trapezoid", 4))',
 			],
 			[

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -309,6 +309,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-flip.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-map.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-map-closure.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-merge.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-sum.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/array-plus.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-4573.php');

tests/PHPStan/Analyser/data/array-merge.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace ArrayMerge;
+
+use function array_merge;
+use function PHPStan\Testing\assertType;
+
+function foo(): void
+{
+	$foo = ['foo' => 17, 'a', 'bar' => 18, 'b'];
+	$bar = [99 => 'b', 'bar' => 19, 98 => 'c'];
+	$baz = array_merge($foo, $bar);
+
+	assertType('array{foo: 17, 0: \'a\', bar: 19, 1: \'b\', 2: \'b\', 3: \'c\'}', $baz);
+}