diff --git a/src/Symfony/DefaultParameterMap.php b/src/Symfony/DefaultParameterMap.php
index fe29b34f..26317468 100644
--- a/src/Symfony/DefaultParameterMap.php
+++ b/src/Symfony/DefaultParameterMap.php
@@ -4,8 +4,9 @@
 
 use PhpParser\Node\Expr;
 use PHPStan\Analyser\Scope;
+use PHPStan\Type\Type;
 use PHPStan\Type\TypeUtils;
-use function count;
+use function array_map;
 
 final class DefaultParameterMap implements ParameterMap
 {
@@ -34,10 +35,13 @@ public function getParameter(string $key): ?ParameterDefinition
 		return $this->parameters[$key] ?? null;
 	}
 
-	public static function getParameterKeyFromNode(Expr $node, Scope $scope): ?string
+	public static function getParameterKeysFromNode(Expr $node, Scope $scope): array
 	{
 		$strings = TypeUtils::getConstantStrings($scope->getType($node));
-		return count($strings) === 1 ? $strings[0]->getValue() : null;
+
+		return array_map(static function (Type $type) {
+			return $type->getValue();
+		}, $strings);
 	}
 
 }
diff --git a/src/Symfony/FakeParameterMap.php b/src/Symfony/FakeParameterMap.php
index 0bf450e7..53acdc3c 100644
--- a/src/Symfony/FakeParameterMap.php
+++ b/src/Symfony/FakeParameterMap.php
@@ -21,9 +21,9 @@ public function getParameter(string $key): ?ParameterDefinition
 		return null;
 	}
 
-	public static function getParameterKeyFromNode(Expr $node, Scope $scope): ?string
+	public static function getParameterKeysFromNode(Expr $node, Scope $scope): array
 	{
-		return null;
+		return [];
 	}
 
 }
diff --git a/src/Symfony/ParameterMap.php b/src/Symfony/ParameterMap.php
index c768e2f2..ff0f5224 100644
--- a/src/Symfony/ParameterMap.php
+++ b/src/Symfony/ParameterMap.php
@@ -15,6 +15,9 @@ public function getParameters(): array;
 
 	public function getParameter(string $key): ?ParameterDefinition;
 
-	public static function getParameterKeyFromNode(Expr $node, Scope $scope): ?string;
+	/**
+	 * @return array<string>
+	 */
+	public static function getParameterKeysFromNode(Expr $node, Scope $scope): array;
 
 }
diff --git a/src/Type/Symfony/ParameterDynamicReturnTypeExtension.php b/src/Type/Symfony/ParameterDynamicReturnTypeExtension.php
index 6a197a8f..b18a386f 100644
--- a/src/Type/Symfony/ParameterDynamicReturnTypeExtension.php
+++ b/src/Type/Symfony/ParameterDynamicReturnTypeExtension.php
@@ -113,7 +113,7 @@ private function getGetTypeFromMethodCall(
 	{
 		// We don't use the method's return type because this won't work properly with lowest and
 		// highest versions of Symfony ("mixed" for lowest, "array|bool|float|integer|string|null" for highest).
-		$returnType = new UnionType([
+		$defaultReturnType = new UnionType([
 			new ArrayType(new MixedType(), new MixedType()),
 			new BooleanType(),
 			new FloatType(),
@@ -122,18 +122,25 @@ private function getGetTypeFromMethodCall(
 			new NullType(),
 		]);
 		if (!isset($methodCall->getArgs()[0])) {
-			return $returnType;
+			return $defaultReturnType;
 		}
 
-		$parameterKey = $this->parameterMap::getParameterKeyFromNode($methodCall->getArgs()[0]->value, $scope);
-		if ($parameterKey !== null) {
+		$parameterKeys = $this->parameterMap::getParameterKeysFromNode($methodCall->getArgs()[0]->value, $scope);
+		if ($parameterKeys === []) {
+			return $defaultReturnType;
+		}
+
+		$returnTypes = [];
+		foreach ($parameterKeys as $parameterKey) {
 			$parameter = $this->parameterMap->getParameter($parameterKey);
-			if ($parameter !== null) {
-				return $this->generalizeTypeFromValue($scope, $parameter->getValue());
+			if ($parameter === null) {
+				return $defaultReturnType;
 			}
+
+			$returnTypes[] = $this->generalizeTypeFromValue($scope, $parameter->getValue());
 		}
 
-		return $returnType;
+		return TypeCombinator::union(...$returnTypes);
 	}
 
 	/**
@@ -211,18 +218,31 @@ private function getHasTypeFromMethodCall(
 		Scope $scope
 	): Type
 	{
-		$returnType = ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
+		$defaultReturnType = ParametersAcceptorSelector::selectSingle($methodReflection->getVariants())->getReturnType();
 		if (!isset($methodCall->getArgs()[0]) || !$this->constantHassers) {
-			return $returnType;
+			return $defaultReturnType;
 		}
 
-		$parameterKey = $this->parameterMap::getParameterKeyFromNode($methodCall->getArgs()[0]->value, $scope);
-		if ($parameterKey !== null) {
+		$parameterKeys = $this->parameterMap::getParameterKeysFromNode($methodCall->getArgs()[0]->value, $scope);
+		if ($parameterKeys === []) {
+			return $defaultReturnType;
+		}
+
+		$has = null;
+		foreach ($parameterKeys as $parameterKey) {
 			$parameter = $this->parameterMap->getParameter($parameterKey);
-			return new ConstantBooleanType($parameter !== null);
+
+			if ($has === null) {
+				$has = $parameter !== null;
+			} elseif (
+				($has === true && $parameter === null)
+				|| ($has === false && $parameter !== null)
+			) {
+				return $defaultReturnType;
+			}
 		}
 
-		return $returnType;
+		return new ConstantBooleanType($has);
 	}
 
 }
diff --git a/tests/Type/Symfony/data/ExampleController.php b/tests/Type/Symfony/data/ExampleController.php
index 89d2b5f8..528b06a7 100644
--- a/tests/Type/Symfony/data/ExampleController.php
+++ b/tests/Type/Symfony/data/ExampleController.php
@@ -116,6 +116,27 @@ public function parameters(ContainerInterface $container, ParameterBagInterface
 		assertType('true', $parameterBag->has('app.binary'));
 		assertType('true', $container->hasParameter('app.constant'));
 		assertType('true', $parameterBag->has('app.constant'));
+
+		$key = rand(0, 1) ? 'app.string' : 'app.int';
+		assertType("int|string", $container->getParameter($key));
+		assertType("int|string", $parameterBag->get($key));
+		assertType("int|string", $this->getParameter($key));
+		assertType('true', $container->hasParameter($key));
+		assertType('true', $parameterBag->has($key));
+
+		$key = rand(0, 1) ? 'app.string' : 'app.foo';
+		assertType("array|bool|float|int|string|null", $container->getParameter($key));
+		assertType("array|bool|float|int|string|null", $parameterBag->get($key));
+		assertType("array|bool|float|int|string|null", $this->getParameter($key));
+		assertType('bool', $container->hasParameter($key));
+		assertType('bool', $parameterBag->has($key));
+
+		$key = rand(0, 1) ? 'app.bar' : 'app.foo';
+		assertType("array|bool|float|int|string|null", $container->getParameter($key));
+		assertType("array|bool|float|int|string|null", $parameterBag->get($key));
+		assertType("array|bool|float|int|string|null", $this->getParameter($key));
+		assertType('false', $container->hasParameter($key));
+		assertType('false', $parameterBag->has($key));
 	}
 
 }