Add array_combine dynamicExtension

conf/config.neon

@@ -761,6 +761,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\ArrayCombineFunctionReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicFunctionReturnTypeExtension
+
 	-
 		class: PHPStan\Type\Php\ArrayCurrentDynamicReturnTypeExtension
 		tags:

src/Php/PhpVersion.php

@@ -91,4 +91,9 @@ public function supportsNamedArguments(): bool
 		return $this->versionId >= 80000;
 	}
 
+	public function throwsTypeErrorForInternalFunctions(): bool
+	{
+		return $this->versionId >= 80000;
+	}
+
 }

src/Type/Php/ArrayCombineFunctionReturnTypeExtension.php

@@ -0,0 +1,106 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Expr\Variable;
+use PHPStan\Analyser\Scope;
+use PHPStan\Php\PhpVersion;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\Type\ArrayType;
+use PHPStan\Type\Constant\ConstantArrayType;
+use PHPStan\Type\Constant\ConstantBooleanType;
+use PHPStan\Type\Constant\ConstantIntegerType;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\MixedType;
+use PHPStan\Type\Type;
+use PHPStan\Type\UnionType;
+
+class ArrayCombineFunctionReturnTypeExtension implements \PHPStan\Type\DynamicFunctionReturnTypeExtension
+{
+
+	private PhpVersion $phpVersion;
+
+	public function __construct(PhpVersion $phpVersion)
+	{
+		$this->phpVersion = $phpVersion;
+	}
+
+	public function isFunctionSupported(FunctionReflection $functionReflection): bool
+	{
+		return $functionReflection->getName() === 'array_combine';
+	}
+
+	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): Type
+	{
+		if (count($functionCall->args) < 2) {
+			return ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
+		}
+
+		$firstArg = $functionCall->args[0]->value;
+		$secondArg = $functionCall->args[1]->value;
+
+		$keysParamType = $scope->getType($firstArg);
+		$valuesParamType = $scope->getType($secondArg);
+
+		if (
+			$keysParamType instanceof ConstantArrayType
+			&& $valuesParamType instanceof ConstantArrayType
+		) {
+			$keyTypes = $keysParamType->getValueTypes();
+			$valueTypes = $valuesParamType->getValueTypes();
+
+			if (count($keyTypes) !== count($valueTypes)) {
+				return new ConstantBooleanType(false);
+			}
+
+			$keyTypes = $this->sanitizeConstantArrayKeyTypes($keyTypes);
+			if ($keyTypes !== null) {
+				return new ConstantArrayType(
+					$keyTypes,
+					$valueTypes
+				);
+			}
+		}
+
+		$arrayType = new ArrayType(
+			$keysParamType instanceof ArrayType ? $keysParamType->getItemType() : new MixedType(),
+			$valuesParamType instanceof ArrayType ? $valuesParamType->getItemType() : new MixedType()
+		);
+
+		if ($this->phpVersion->throwsTypeErrorForInternalFunctions()) {
+			return $arrayType;
+		}
+
+		if ($firstArg instanceof Variable && $secondArg instanceof Variable && $firstArg->name === $secondArg->name) {
+			return $arrayType;
+		}
+
+		return new UnionType([$arrayType, new ConstantBooleanType(false)]);
+	}
+
+	/**
+	 * @param array<int, Type> $types
+	 *
+	 * @return array<int, ConstantIntegerType|ConstantStringType>|null
+	 */
+	private function sanitizeConstantArrayKeyTypes(array $types): ?array
+	{
+		$sanitizedTypes = [];
+
+		foreach ($types as $type) {
+			if (
+				!$type instanceof ConstantIntegerType
+				&& !$type instanceof ConstantStringType
+			) {
+				return null;
+			}
+
+			$sanitizedTypes[] = $type;
+		}
+
+		return $sanitizedTypes;
+	}
+
+}

tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -4993,8 +4993,36 @@ public function dataArrayFunctions(): array
 			],
 			[
 				PHP_VERSION_ID < 80000 ? 'array|false' : 'array',
+				'array_combine($array, $array2)',
+			],
+			[
+				'array(1 => 2)',
 				'array_combine([1], [2])',
 			],
+			[
+				'false',
+				'array_combine([1, 2], [3])',
+			],
+			[
+				'array(\'a\' => \'d\', \'b\' => \'e\', \'c\' => \'f\')',
+				'array_combine([\'a\', \'b\', \'c\'], [\'d\', \'e\', \'f\'])',
+			],
+			[
+				PHP_VERSION_ID < 80000 ? 'array<1|2|3, mixed>|false' : 'array<1|2|3, mixed>',
+				'array_combine([1, 2, 3], $array)',
+			],
+			[
+				PHP_VERSION_ID < 80000 ? 'array<1|2|3>|false' : 'array<1|2|3>',
+				'array_combine($array, [1, 2, 3])',
+			],
+			[
+				'array',
+				'array_combine($array, $array)',
+			],
+			[
+				'array<string, string>',
+				'array_combine($stringArray, $stringArray)',
+			],
 			[
 				'array<0|1|2, 1|2|3>',
 				'array_diff_assoc($integers, [])',

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

@@ -160,6 +160,12 @@
 /** @var array $array */
 $array = doFoo();
 
+/** @var array $array2 */
+$array2 = doFoo();
+
+/** @var string[] $stringArray */
+$stringArray = doFoo();
+
 $slicedOffset = array_slice(['4' => 'foo', 1 => 'bar', 'baz' => 'qux', 0 => 'quux', 'quuz' => 'corge'], 0, null, false);
 $slicedOffsetWithKeys = array_slice(['4' => 'foo', 1 => 'bar', 'baz' => 'qux', 0 => 'quux', 'quuz' => 'corge'], 0, null, true);