Mutation definitions break code: "Uncaught Error: Function name must be a string"

[nleco]

When I try to define mutations, my code breaks. I also tried one of the examples and I get the same error:
PHP Notice: Undefined index: type in /Users/....<stuff>..../vendor/webonyx/graphql-php/src/Type/Definition/FieldArgument.php on line 84
Uncaught Error: Function name must be a string

I have a UserType set up. The Query type uses it.

use GraphQL\Type\Definition\ObjectType;
use GraphQL\Type\Definition\Type;

$UserType = new ObjectType([
  'name' => 'User',
  'description' => 'User type',
  'fields' => function () {
    return [
      'id' => Type::int(),
      'created_at' => Type::int(),
      'updated_at' => Type::int(),
      'name' => Type::string(),
      'email' => Type::string(),
      'password' => Type::string(),
    ];
  },
]);

The mutation type is defined as follows:

use GraphQL\Type\Definition\ObjectType;
use GraphQL\Type\Definition\Type;
use App\Models\User;

$rootMutation = new ObjectType([
  'name' => 'Mutation',
  'fields' => [
    'createUser' => [
      'type' => $UserType,
      'args' => [
        'input' => [
          'name' => Type::nonNull(Type::string()),
          'email' => Type::nonNull(Type::string()),
          'password' => Type::nonNull(Type::string()),
          'password_confirmation' => Type::nonNull(Type::string()),
        ],
      ],
      'resolve' => static function ($root, $args) {
        $input = $args['input'];

        if ($input['password'] !== $input['password_confirmation']) {
          throw new Exception('Passwords do not match');
        }

        $user = new User([
          'name' => $input['name'],
          'email' => $input['email'],
          'password' => $input['password'],
        ]);
        $user->save();
        return $user->toArray();
      },
    ],
    'editUser' => [
      'type' => $UserType,
      'args' => [
        'input' => [
          'name' => Type::nonNull(Type::string()),
          'email' => Type::nonNull(Type::string()),
          'password' => Type::nonNull(Type::string()),
        ],
      ],
      'resolve' => static function ($root, $args) {
        $input = $args['input'];
        $password = null;

        $user = User::find($input['id']);
        $user->name = isset($input['name']) ? $input['name'] : $user->name;
        $user->email = isset($input['email']) ? $input['email'] : $user->email;
        $user->password = isset($password) ? $password : $user->password;

        $user->save();
        return $user->toArray();
      },
    ],
  ],
]);

I feel like I'm missing something basic.

my composer has: "webonyx/graphql-php": "^14.3",
And I am using: "version": "v14.11.0"

[nleco]

I spent 2 days trying to figure it out, only to ask here and THEN figuring it out.

I had wrapped my args into an 'input' key. This is a no-no. I had to use an InputObjectType.

$CreateUserInputType = new InputObjectType([
  'name' => 'CreateUserInput',
  'fields' => [
    'name' => Type::nonNull(Type::string()),
    'email' => Type::nonNull(Type::string()),
    'password' => Type::nonNull(Type::string()),
    'password_confirmation' => Type::nonNull(Type::string()),
  ],
]);

and then use THAT as the input

$rootMutation = new ObjectType([
  'name' => 'Mutation',
  'fields' => [
    'createUser' => [
      'type' => $UserType,
      'args' => [
        'input' => [
          'type' => $CreateUserInputType,
        ],
      ],
      'resolve' => static function ($root, $args) {
        $input = $args['input'];

        if ($input['password'] !== $input['password_confirmation']) {
          throw new Exception('Passwords do not match');
        }

        $user = new User([
          'name' => $input['name'],
          'email' => $input['email'],
          'password' => $input['password'],
        ]);
        $user->save();
        return $user->toArray();
      },
    ],