Check by the validation kind method instead of the full constant

lib/simple_form/components/maxlength.rb

@@ -23,7 +23,7 @@ module SimpleForm
       end
 
       def find_length_validator
-        find_validator(ActiveModel::Validations::LengthValidator)
+        find_validator(:length)
       end
 
       def has_tokenizer?(length_validator)

lib/simple_form/components/min_max.rb

@@ -33,7 +33,7 @@ module SimpleForm
       end
 
       def find_numericality_validator
-        find_validator(ActiveModel::Validations::NumericalityValidator)
+        find_validator(:numericality)
       end
 
       def evaluate_numericality_validator_option(option)

lib/simple_form/components/pattern.rb

@@ -19,7 +19,7 @@ module SimpleForm
       end
 
       def find_pattern_validator
-        find_validator(ActiveModel::Validations::FormatValidator)
+        find_validator(:format)
       end
 
       def evaluate_format_validator_option(option)

lib/simple_form/helpers/validators.rb

@@ -36,8 +36,8 @@ module SimpleForm
         end
       end
 
-      def find_validator(validator)
-        attribute_validators.find { |v| validator === v } if has_validators?
+      def find_validator(kind)
+        attribute_validators.find { |v| v.kind == kind } if has_validators?
       end
     end
   end