Oops, string is no child of Object

addons/form/nodes/FormLabel.gd

@@ -21,6 +21,26 @@ class_name FormLabel extends Label
 ## "The selected input is not an input according to Form.is_input() or null"
 @export var nonstandard_input := false
 
+## Validator 
+@export var validator: Validator:
+	set(new_val):
+		if validator != null && input != null:
+				push_error("Validator must be compatible with the type of subject")
+				return
+			if input.get_theme_stylebox("normal") == null:
+				validator.style_valid = input.get_theme_stylebox("normal")
+			validator = new_val
+
+## Name of the property to validate
+@export var subject: StringName:
+	set(new_val):
+		if input == null:
+			subject = new_val
+		elif has_property(input, new_val) && (validator == null || typeof(input[new_val]) == validator.get_type()):
+			subject = new_val
+		else:
+			push_error("Validator must be compatible with the type of subject")
+
 ## "Input value must not be empty"
 @export var input_required := false:
 	set(new_val):

addons/form/nodes/Validator.gd

@@ -12,7 +12,7 @@ var valid := false
 var broken_rules := {}
 
 ## Validates subject against all rules and returns validity
-func validate(subject: Object) -> bool:
+func validate(subject) -> bool:
 	if typeof(subject) != get_type():
 		push_error("Subject must be of type ", get_type(), " (see Variant.Type)")
 	broken_rules = {}

addons/form/nodes/Validators/StringValidator.gd

@@ -93,8 +93,10 @@ func _on_text_changed(
 ## Validates given text against all rules and returns validity
 func validate(
 	## Text to validate
-	subject: Object
+	subject
 ) -> bool:
+	if !(subject is String):
+		return
 	super.validate(subject)
 	var _regex := RegEx.new()