Compute native callable parameters from array args for array_map and array_filter

For constant arrays passed to array_map/array_filter, the native types
are known (e.g. literal string unions), but the callback parameter's
native PHP type is just `callable` which loses this information.

Tag array_filter callbacks with the array expression (like ArrayMapArgVisitor
does for array_map), then compute native callable parameters from the actual
array arguments' native types in processClosureNode, processArrowFunctionNode,
and ClosureTypeResolver.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Analyser/ExprHandler/Helper/ClosureTypeResolver.php

@@ -20,6 +20,7 @@
 use PHPStan\Node\ExecutionEndNode;
 use PHPStan\Node\InvalidateExprNode;
 use PHPStan\Node\PropertyAssignNode;
+use PHPStan\Parser\ArrayFilterArgVisitor;
 use PHPStan\Parser\ArrayMapArgVisitor;
 use PHPStan\Parser\ImmediatelyInvokedClosureVisitor;
 use PHPStan\Reflection\ExtendedParameterReflection;
@@ -99,12 +100,13 @@ public function getClosureType(
 
 		$callableParameters = null;
 		$nativeCallableParameters = null;
-		$arrayMapArgs = $expr->getAttribute(ArrayMapArgVisitor::ATTRIBUTE_NAME);
+		$arrayArgs = $expr->getAttribute(ArrayMapArgVisitor::ATTRIBUTE_NAME)
+			?? $expr->getAttribute(ArrayFilterArgVisitor::CALLBACK_ATTRIBUTE_NAME);
 		$immediatelyInvokedArgs = $expr->getAttribute(ImmediatelyInvokedClosureVisitor::ARGS_ATTRIBUTE_NAME);
-		if ($arrayMapArgs !== null) {
+		if ($arrayArgs !== null) {
 			$callableParameters = [];
 			$nativeCallableParameters = [];
-			foreach ($arrayMapArgs as $funcCallArg) {
+			foreach ($arrayArgs as $funcCallArg) {
 				$callableParameters[] = new DummyParameter('item', $scope->getType($funcCallArg->value)->getIterableValueType(), optional: false, passedByReference: PassedByReference::createNo(), variadic: false, defaultValue: null);
 				$nativeCallableParameters[] = new DummyParameter('item', $scope->getNativeType($funcCallArg->value)->getIterableValueType(), optional: false, passedByReference: PassedByReference::createNo(), variadic: false, defaultValue: null);
 			}

src/Analyser/NodeScopeResolver.php

@@ -107,6 +107,8 @@
 use PHPStan\Node\UnreachableStatementNode;
 use PHPStan\Node\VariableAssignNode;
 use PHPStan\Node\VarTagChangedExpressionTypeNode;
+use PHPStan\Parser\ArrayFilterArgVisitor;
+use PHPStan\Parser\ArrayMapArgVisitor;
 use PHPStan\Parser\ArrowFunctionArgVisitor;
 use PHPStan\Parser\ClosureArgVisitor;
 use PHPStan\Parser\ImmediatelyInvokedClosureVisitor;
@@ -2717,7 +2719,8 @@ public function processClosureNode(
 
 		$closureCallArgs = $expr->getAttribute(ClosureArgVisitor::ATTRIBUTE_NAME);
 		$callableParameters = $this->createCallableParameters($scope, $expr, $closureCallArgs, $passedToType);
-		$nativeCallableParameters = $this->createNativeCallableParameters($scope, $expr, $closureCallArgs, $nativePassedToType);
+		$nativeCallableParameters = $this->createNativeCallableParametersFromArrayArgs($scope, $expr)
+			?? $this->createNativeCallableParameters($scope, $expr, $closureCallArgs, $nativePassedToType);
 
 		$useScope = $scope;
 		foreach ($expr->uses as $use) {
@@ -2927,7 +2930,8 @@ public function processArrowFunctionNode(
 
 		$arrowFunctionCallArgs = $expr->getAttribute(ArrowFunctionArgVisitor::ATTRIBUTE_NAME);
 		$callableParameters = $this->createCallableParameters($scope, $expr, $arrowFunctionCallArgs, $passedToType);
-		$nativeCallableParameters = $this->createNativeCallableParameters($scope, $expr, $arrowFunctionCallArgs, $nativePassedToType);
+		$nativeCallableParameters = $this->createNativeCallableParametersFromArrayArgs($scope, $expr)
+			?? $this->createNativeCallableParameters($scope, $expr, $arrowFunctionCallArgs, $nativePassedToType);
 		$arrowFunctionScope = $scope->enterArrowFunction($expr, $callableParameters, $nativeCallableParameters);
 		$arrowFunctionType = $arrowFunctionScope->getAnonymousFunctionReflection();
 		if ($arrowFunctionType === null) {
@@ -2957,6 +2961,23 @@ public function createNativeCallableParameters(Scope $scope, Expr $closureExpr,
 		return $this->doCreateCallableParameters($scope, $closureExpr, $args, $nativePassedToType, static fn (Scope $s, Expr $e) => $s->getNativeType($e));
 	}
 
+	/**
+	 * @return ParameterReflection[]|null
+	 */
+	private function createNativeCallableParametersFromArrayArgs(Scope $scope, Expr $closureExpr): ?array
+	{
+		$arrayArgs = $closureExpr->getAttribute(ArrayMapArgVisitor::ATTRIBUTE_NAME)
+			?? $closureExpr->getAttribute(ArrayFilterArgVisitor::CALLBACK_ATTRIBUTE_NAME);
+		if ($arrayArgs === null) {
+			return null;
+		}
+		$params = [];
+		foreach ($arrayArgs as $funcCallArg) {
+			$params[] = new DummyParameter('item', $scope->getNativeType($funcCallArg->value)->getIterableValueType(), false, PassedByReference::createNo(), false, null);
+		}
+		return $params;
+	}
+
 	/**
 	 * @param Node\Arg[]|null $args
 	 * @param Closure(Scope, Expr): Type $typeGetter

src/Parser/ArrayFilterArgVisitor.php

@@ -13,6 +13,8 @@ final class ArrayFilterArgVisitor extends NodeVisitorAbstract
 
 	public const ATTRIBUTE_NAME = 'isArrayFilterArg';
 
+	public const CALLBACK_ATTRIBUTE_NAME = 'arrayFilterCallbackArgs';
+
 	#[Override]
 	public function enterNode(Node $node): ?Node
 	{
@@ -23,6 +25,9 @@ public function enterNode(Node $node): ?Node
 				if (isset($args[0])) {
 					$args[0]->setAttribute(self::ATTRIBUTE_NAME, true);
 				}
+				if (isset($args[0]) && isset($args[1]) && !isset($args[2])) {
+					$args[1]->value->setAttribute(self::CALLBACK_ATTRIBUTE_NAME, [$args[0]]);
+				}
 			}
 		}
 		return null;