diff --git a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
index a608280e8cd..d8290e4aab9 100644
--- a/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
+++ b/modules/openapi-generator/src/main/resources/r/modelGeneric.mustache
@@ -367,46 +367,46 @@
       {{^isNullable}}
       {{#required}}
       # check if the required `{{{name}}}` is null
-      if (is.null(`{{{name}}}`)) {
-        FALSE
+      if (is.null(self$`{{{name}}}`)) {
+        return(FALSE)
       }
 
       {{/required}}
       {{/isNullable}}
       {{#hasValidation}}
       {{#maxLength}}
-      if (nchar(`{{{name}}}`) > {{maxLength}}) {
-        FALSE
+      if (nchar(self$`{{{name}}}`) > {{maxLength}}) {
+        return(FALSE)
       }
       {{/maxLength}}
       {{#minLength}}
-      if (nchar(`{{{name}}}`) < {{minLength}}) {
-        FALSE
+      if (nchar(self$`{{{name}}}`) < {{minLength}}) {
+        return(FALSE)
       }
       {{/minLength}}
       {{#maximum}}
-      if (`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
-        FALSE
+      if (self$`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
+        return(FALSE)
       }
       {{/maximum}}
       {{#minimum}}
-      if (`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
-        FALSE
+      if (self$`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
+        return(FALSE)
       }
       {{/minimum}}
       {{#pattern}}
-      if (!str_detect(`{{{name}}}`, "{{{pattern}}}")) {
-        FALSE
+      if (!str_detect(self$`{{{name}}}`, "{{{pattern}}}")) {
+        return(FALSE)
       }
       {{/pattern}}
       {{#maxItems}}
-      if (length(`{{{name}}}`) > {{maxItems}}) {
-        FALSE
+      if (length(self$`{{{name}}}`) > {{maxItems}}) {
+        return(FALSE)
       }
       {{/maxItems}}
       {{#minItems}}
-      if (length(`{{{name}}}`) < {{minItems}}) {
-        FALSE
+      if (length(self$`{{{name}}}`) < {{minItems}}) {
+        return(FALSE)
       }
       {{/minItems}}
 
@@ -427,46 +427,46 @@
       {{^isNullable}}
       {{#required}}
       # check if the required `{{{name}}}` is null
-      if (is.null(`{{{name}}}`)) {
-        invalid_fields[`{{{name}}}`] = "Non-nullable required field `{{{name}}}` cannot be null."
+      if (is.null(self$`{{{name}}}`)) {
+        invalid_fields["{{{name}}}"] = "Non-nullable required field `{{{name}}}` cannot be null."
       }
 
       {{/required}}
       {{/isNullable}}
       {{#hasValidation}}
       {{#maxLength}}
-      if (nchar(`{{{name}}}`) > {{maxLength}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, must be smaller than or equal to {{maxLength}}."
+      if (nchar(self$`{{{name}}}`) > {{maxLength}}) {
+        invalid_fields["{{{name}}}"] = "Invalid length for `{{{name}}}`, must be smaller than or equal to {{maxLength}}."
       }
       {{/maxLength}}
       {{#minLength}}
-      if (nchar(`{{{name}}}`) < {{minLength}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, must be bigger than or equal to {{minLength}}."
+      if (nchar(self$`{{{name}}}`) < {{minLength}}) {
+        invalid_fields["{{{name}}}"] = "Invalid length for `{{{name}}}`, must be bigger than or equal to {{minLength}}."
       }
       {{/minLength}}
       {{#maximum}}
-      if (`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must be smaller than {{^exclusiveMaximum}}or equal to {{/exclusiveMaximum}}{{maximum}}."
+      if (self$`{{{name}}}` >{{#exclusiveMaximum}}={{/exclusiveMaximum}} {{maximum}}) {
+        invalid_fields["{{{name}}}"] = "Invalid value for `{{{name}}}`, must be smaller than {{^exclusiveMaximum}}or equal to {{/exclusiveMaximum}}{{maximum}}."
       }
       {{/maximum}}
       {{#minimum}}
-      if (`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must be bigger than {{^exclusiveMinimum}}or equal to {{/exclusiveMinimum}}{{minimum}}."
+      if (self$`{{{name}}}` <{{#exclusiveMinimum}}={{/exclusiveMinimum}} {{minimum}}) {
+        invalid_fields["{{{name}}}"] = "Invalid value for `{{{name}}}`, must be bigger than {{^exclusiveMinimum}}or equal to {{/exclusiveMinimum}}{{minimum}}."
       }
       {{/minimum}}
       {{#pattern}}
-      if (!str_detect(`{{{name}}}`, "{{{pattern}}}")) {
-        invalid_fields[`{{{name}}}`] = "Invalid value for `{{{name}}}`, must conform to the pattern {{{pattern}}}."
+      if (!str_detect(self$`{{{name}}}`, "{{{pattern}}}")) {
+        invalid_fields["{{{name}}}"] = "Invalid value for `{{{name}}}`, must conform to the pattern {{{pattern}}}."
       }
       {{/pattern}}
       {{#maxItems}}
-      if (length(`{{{name}}}`) > {{maxItems}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{name}}}`, number of items must be less than or equal to {{maxItems}}."
+      if (length(self$`{{{name}}}`) > {{maxItems}}) {
+        invalid_fields["{{{name}}}"] = "Invalid length for `{{{name}}}`, number of items must be less than or equal to {{maxItems}}."
       }
       {{/maxItems}}
       {{#minItems}}
-      if (length(`{{{name}}}`) < {{minItems}}) {
-        invalid_fields[`{{{name}}}`] = "Invalid length for `{{{param}}}`, number of items must be greater than or equal to {{minItems}}."
+      if (length(self$`{{{name}}}`) < {{minItems}}) {
+        invalid_fields["{{{name}}}"] = "Invalid length for `{{{param}}}`, number of items must be greater than or equal to {{minItems}}."
       }
       {{/minItems}}
 
@@ -475,4 +475,4 @@
       invalid_fields
     }
   )
-)
\ No newline at end of file
+)
diff --git a/samples/client/petstore/R-httr2/R/allof_tag_api_response.R b/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
index 8a148dbd067..793f2bcf1a7 100644
--- a/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
+++ b/samples/client/petstore/R-httr2/R/allof_tag_api_response.R
@@ -234,3 +234,4 @@ AllofTagApiResponse <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/animal.R b/samples/client/petstore/R-httr2/R/animal.R
index 9189e9c1597..05778bcbeba 100644
--- a/samples/client/petstore/R-httr2/R/animal.R
+++ b/samples/client/petstore/R-httr2/R/animal.R
@@ -157,8 +157,8 @@ Animal <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -173,11 +173,12 @@ Animal <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/basque_pig.R b/samples/client/petstore/R-httr2/R/basque_pig.R
index 3a4ca70654e..6c626a55eca 100644
--- a/samples/client/petstore/R-httr2/R/basque_pig.R
+++ b/samples/client/petstore/R-httr2/R/basque_pig.R
@@ -163,13 +163,13 @@ BasquePig <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       # check if the required `color` is null
-      if (is.null(`color`)) {
-        FALSE
+      if (is.null(self$`color`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -184,16 +184,17 @@ BasquePig <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       # check if the required `color` is null
-      if (is.null(`color`)) {
-        invalid_fields[`color`] = "Non-nullable required field `color` cannot be null."
+      if (is.null(self$`color`)) {
+        invalid_fields["color"] = "Non-nullable required field `color` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/cat.R b/samples/client/petstore/R-httr2/R/cat.R
index 1d9a7017f55..16ea3003ffc 100644
--- a/samples/client/petstore/R-httr2/R/cat.R
+++ b/samples/client/petstore/R-httr2/R/cat.R
@@ -181,8 +181,8 @@ Cat <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -197,11 +197,12 @@ Cat <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/cat_all_of.R b/samples/client/petstore/R-httr2/R/cat_all_of.R
index 8f6055ccd29..8a0841346f1 100644
--- a/samples/client/petstore/R-httr2/R/cat_all_of.R
+++ b/samples/client/petstore/R-httr2/R/cat_all_of.R
@@ -142,3 +142,4 @@ CatAllOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/category.R b/samples/client/petstore/R-httr2/R/category.R
index 0bd55f34ce2..bc8cbab3637 100644
--- a/samples/client/petstore/R-httr2/R/category.R
+++ b/samples/client/petstore/R-httr2/R/category.R
@@ -150,8 +150,8 @@ Category <- R6::R6Class(
     #' @return true if the values in all fields are valid.
     #' @export
     isValid = function() {
-      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
-        FALSE
+      if (!str_detect(self$`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        return(FALSE)
       }
 
       TRUE
@@ -165,11 +165,12 @@ Category <- R6::R6Class(
     #' @export
     getInvalidFields = function() {
       invalid_fields <- list()
-      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
-        invalid_fields[`name`] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
+      if (!str_detect(self$`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        invalid_fields["name"] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/danish_pig.R b/samples/client/petstore/R-httr2/R/danish_pig.R
index a7584f4700b..a675c01e28e 100644
--- a/samples/client/petstore/R-httr2/R/danish_pig.R
+++ b/samples/client/petstore/R-httr2/R/danish_pig.R
@@ -163,13 +163,13 @@ DanishPig <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       # check if the required `size` is null
-      if (is.null(`size`)) {
-        FALSE
+      if (is.null(self$`size`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -184,16 +184,17 @@ DanishPig <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       # check if the required `size` is null
-      if (is.null(`size`)) {
-        invalid_fields[`size`] = "Non-nullable required field `size` cannot be null."
+      if (is.null(self$`size`)) {
+        invalid_fields["size"] = "Non-nullable required field `size` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/dog.R b/samples/client/petstore/R-httr2/R/dog.R
index 59f39c2e091..ee057d1dd9b 100644
--- a/samples/client/petstore/R-httr2/R/dog.R
+++ b/samples/client/petstore/R-httr2/R/dog.R
@@ -181,8 +181,8 @@ Dog <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -197,11 +197,12 @@ Dog <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/dog_all_of.R b/samples/client/petstore/R-httr2/R/dog_all_of.R
index 8956ffc3771..cacc9a8be59 100644
--- a/samples/client/petstore/R-httr2/R/dog_all_of.R
+++ b/samples/client/petstore/R-httr2/R/dog_all_of.R
@@ -142,3 +142,4 @@ DogAllOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/model_api_response.R b/samples/client/petstore/R-httr2/R/model_api_response.R
index 713ab123bb7..671de10dec2 100644
--- a/samples/client/petstore/R-httr2/R/model_api_response.R
+++ b/samples/client/petstore/R-httr2/R/model_api_response.R
@@ -188,3 +188,4 @@ ModelApiResponse <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/nested_one_of.R b/samples/client/petstore/R-httr2/R/nested_one_of.R
index 95840db010f..251f18325e6 100644
--- a/samples/client/petstore/R-httr2/R/nested_one_of.R
+++ b/samples/client/petstore/R-httr2/R/nested_one_of.R
@@ -167,3 +167,4 @@ NestedOneOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/order.R b/samples/client/petstore/R-httr2/R/order.R
index 892cb94a4d4..d2acccd9416 100644
--- a/samples/client/petstore/R-httr2/R/order.R
+++ b/samples/client/petstore/R-httr2/R/order.R
@@ -257,3 +257,4 @@ Order <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/pet.R b/samples/client/petstore/R-httr2/R/pet.R
index e8537ad77d0..aa2a375b50d 100644
--- a/samples/client/petstore/R-httr2/R/pet.R
+++ b/samples/client/petstore/R-httr2/R/pet.R
@@ -260,13 +260,13 @@ Pet <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `name` is null
-      if (is.null(`name`)) {
-        FALSE
+      if (is.null(self$`name`)) {
+        return(FALSE)
       }
 
       # check if the required `photoUrls` is null
-      if (is.null(`photoUrls`)) {
-        FALSE
+      if (is.null(self$`photoUrls`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -281,16 +281,17 @@ Pet <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `name` is null
-      if (is.null(`name`)) {
-        invalid_fields[`name`] = "Non-nullable required field `name` cannot be null."
+      if (is.null(self$`name`)) {
+        invalid_fields["name"] = "Non-nullable required field `name` cannot be null."
       }
 
       # check if the required `photoUrls` is null
-      if (is.null(`photoUrls`)) {
-        invalid_fields[`photoUrls`] = "Non-nullable required field `photoUrls` cannot be null."
+      if (is.null(self$`photoUrls`)) {
+        invalid_fields["photoUrls"] = "Non-nullable required field `photoUrls` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/special.R b/samples/client/petstore/R-httr2/R/special.R
index 5027b80757e..733ddf057dd 100644
--- a/samples/client/petstore/R-httr2/R/special.R
+++ b/samples/client/petstore/R-httr2/R/special.R
@@ -257,3 +257,4 @@ Special <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/tag.R b/samples/client/petstore/R-httr2/R/tag.R
index e0cff8390fe..871a0a11811 100644
--- a/samples/client/petstore/R-httr2/R/tag.R
+++ b/samples/client/petstore/R-httr2/R/tag.R
@@ -165,3 +165,4 @@ Tag <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/update_pet_request.R b/samples/client/petstore/R-httr2/R/update_pet_request.R
index fd573b5a8e3..b5e78e331bf 100644
--- a/samples/client/petstore/R-httr2/R/update_pet_request.R
+++ b/samples/client/petstore/R-httr2/R/update_pet_request.R
@@ -166,3 +166,4 @@ UpdatePetRequest <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/R/user.R b/samples/client/petstore/R-httr2/R/user.R
index e99de33bdfc..bccd1511946 100644
--- a/samples/client/petstore/R-httr2/R/user.R
+++ b/samples/client/petstore/R-httr2/R/user.R
@@ -303,3 +303,4 @@ User <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R-httr2/tests/testthat/test_petstore.R b/samples/client/petstore/R-httr2/tests/testthat/test_petstore.R
index 2e9aa2f8842..bd5f6d326b6 100644
--- a/samples/client/petstore/R-httr2/tests/testthat/test_petstore.R
+++ b/samples/client/petstore/R-httr2/tests/testthat/test_petstore.R
@@ -242,6 +242,24 @@ test_that("Tests special item names", {
 
 })
 
+test_that ("Tests validations", {
+  invalid_pet <- Pet$new()
+
+  expect_false(invalid_pet$isValid())
+
+  invalid_fields <- invalid_pet$getInvalidFields()
+  expect_equal(invalid_fields[["name"]], "Non-nullable required field `name` cannot be null.")
+  expect_equal(invalid_fields[["photoUrls"]], "Non-nullable required field `photoUrls` cannot be null.")
+
+  # fix invalid fields
+  invalid_pet$name <- "valid pet"
+  invalid_pet$photoUrls <- list("photo_test", "second test")
+
+  expect_true(invalid_pet$isValid())
+  expect_equal(invalid_pet$getInvalidFields(), list())
+
+})
+
 test_that("Tests oneOf", {
   basque_pig_json <-
   '{"className": "BasquePig", "color": "red"}'
diff --git a/samples/client/petstore/R/R/allof_tag_api_response.R b/samples/client/petstore/R/R/allof_tag_api_response.R
index 8a148dbd067..793f2bcf1a7 100644
--- a/samples/client/petstore/R/R/allof_tag_api_response.R
+++ b/samples/client/petstore/R/R/allof_tag_api_response.R
@@ -234,3 +234,4 @@ AllofTagApiResponse <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/animal.R b/samples/client/petstore/R/R/animal.R
index 9189e9c1597..05778bcbeba 100644
--- a/samples/client/petstore/R/R/animal.R
+++ b/samples/client/petstore/R/R/animal.R
@@ -157,8 +157,8 @@ Animal <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -173,11 +173,12 @@ Animal <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/basque_pig.R b/samples/client/petstore/R/R/basque_pig.R
index 3a4ca70654e..6c626a55eca 100644
--- a/samples/client/petstore/R/R/basque_pig.R
+++ b/samples/client/petstore/R/R/basque_pig.R
@@ -163,13 +163,13 @@ BasquePig <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       # check if the required `color` is null
-      if (is.null(`color`)) {
-        FALSE
+      if (is.null(self$`color`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -184,16 +184,17 @@ BasquePig <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       # check if the required `color` is null
-      if (is.null(`color`)) {
-        invalid_fields[`color`] = "Non-nullable required field `color` cannot be null."
+      if (is.null(self$`color`)) {
+        invalid_fields["color"] = "Non-nullable required field `color` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/cat.R b/samples/client/petstore/R/R/cat.R
index 1d9a7017f55..16ea3003ffc 100644
--- a/samples/client/petstore/R/R/cat.R
+++ b/samples/client/petstore/R/R/cat.R
@@ -181,8 +181,8 @@ Cat <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -197,11 +197,12 @@ Cat <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/cat_all_of.R b/samples/client/petstore/R/R/cat_all_of.R
index 8f6055ccd29..8a0841346f1 100644
--- a/samples/client/petstore/R/R/cat_all_of.R
+++ b/samples/client/petstore/R/R/cat_all_of.R
@@ -142,3 +142,4 @@ CatAllOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/category.R b/samples/client/petstore/R/R/category.R
index 0bd55f34ce2..bc8cbab3637 100644
--- a/samples/client/petstore/R/R/category.R
+++ b/samples/client/petstore/R/R/category.R
@@ -150,8 +150,8 @@ Category <- R6::R6Class(
     #' @return true if the values in all fields are valid.
     #' @export
     isValid = function() {
-      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
-        FALSE
+      if (!str_detect(self$`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        return(FALSE)
       }
 
       TRUE
@@ -165,11 +165,12 @@ Category <- R6::R6Class(
     #' @export
     getInvalidFields = function() {
       invalid_fields <- list()
-      if (!str_detect(`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
-        invalid_fields[`name`] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
+      if (!str_detect(self$`name`, "^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$")) {
+        invalid_fields["name"] = "Invalid value for `name`, must conform to the pattern ^[a-zA-Z0-9]+[a-zA-Z0-9\\.\\-_]*[a-zA-Z0-9]+$."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/danish_pig.R b/samples/client/petstore/R/R/danish_pig.R
index a7584f4700b..a675c01e28e 100644
--- a/samples/client/petstore/R/R/danish_pig.R
+++ b/samples/client/petstore/R/R/danish_pig.R
@@ -163,13 +163,13 @@ DanishPig <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       # check if the required `size` is null
-      if (is.null(`size`)) {
-        FALSE
+      if (is.null(self$`size`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -184,16 +184,17 @@ DanishPig <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       # check if the required `size` is null
-      if (is.null(`size`)) {
-        invalid_fields[`size`] = "Non-nullable required field `size` cannot be null."
+      if (is.null(self$`size`)) {
+        invalid_fields["size"] = "Non-nullable required field `size` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/dog.R b/samples/client/petstore/R/R/dog.R
index 59f39c2e091..ee057d1dd9b 100644
--- a/samples/client/petstore/R/R/dog.R
+++ b/samples/client/petstore/R/R/dog.R
@@ -181,8 +181,8 @@ Dog <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        FALSE
+      if (is.null(self$`className`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -197,11 +197,12 @@ Dog <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `className` is null
-      if (is.null(`className`)) {
-        invalid_fields[`className`] = "Non-nullable required field `className` cannot be null."
+      if (is.null(self$`className`)) {
+        invalid_fields["className"] = "Non-nullable required field `className` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/dog_all_of.R b/samples/client/petstore/R/R/dog_all_of.R
index 8956ffc3771..cacc9a8be59 100644
--- a/samples/client/petstore/R/R/dog_all_of.R
+++ b/samples/client/petstore/R/R/dog_all_of.R
@@ -142,3 +142,4 @@ DogAllOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/model_api_response.R b/samples/client/petstore/R/R/model_api_response.R
index 713ab123bb7..671de10dec2 100644
--- a/samples/client/petstore/R/R/model_api_response.R
+++ b/samples/client/petstore/R/R/model_api_response.R
@@ -188,3 +188,4 @@ ModelApiResponse <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/nested_one_of.R b/samples/client/petstore/R/R/nested_one_of.R
index 95840db010f..251f18325e6 100644
--- a/samples/client/petstore/R/R/nested_one_of.R
+++ b/samples/client/petstore/R/R/nested_one_of.R
@@ -167,3 +167,4 @@ NestedOneOf <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/order.R b/samples/client/petstore/R/R/order.R
index 892cb94a4d4..d2acccd9416 100644
--- a/samples/client/petstore/R/R/order.R
+++ b/samples/client/petstore/R/R/order.R
@@ -257,3 +257,4 @@ Order <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/pet.R b/samples/client/petstore/R/R/pet.R
index e8537ad77d0..aa2a375b50d 100644
--- a/samples/client/petstore/R/R/pet.R
+++ b/samples/client/petstore/R/R/pet.R
@@ -260,13 +260,13 @@ Pet <- R6::R6Class(
     #' @export
     isValid = function() {
       # check if the required `name` is null
-      if (is.null(`name`)) {
-        FALSE
+      if (is.null(self$`name`)) {
+        return(FALSE)
       }
 
       # check if the required `photoUrls` is null
-      if (is.null(`photoUrls`)) {
-        FALSE
+      if (is.null(self$`photoUrls`)) {
+        return(FALSE)
       }
 
       TRUE
@@ -281,16 +281,17 @@ Pet <- R6::R6Class(
     getInvalidFields = function() {
       invalid_fields <- list()
       # check if the required `name` is null
-      if (is.null(`name`)) {
-        invalid_fields[`name`] = "Non-nullable required field `name` cannot be null."
+      if (is.null(self$`name`)) {
+        invalid_fields["name"] = "Non-nullable required field `name` cannot be null."
       }
 
       # check if the required `photoUrls` is null
-      if (is.null(`photoUrls`)) {
-        invalid_fields[`photoUrls`] = "Non-nullable required field `photoUrls` cannot be null."
+      if (is.null(self$`photoUrls`)) {
+        invalid_fields["photoUrls"] = "Non-nullable required field `photoUrls` cannot be null."
       }
 
       invalid_fields
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/special.R b/samples/client/petstore/R/R/special.R
index 5027b80757e..733ddf057dd 100644
--- a/samples/client/petstore/R/R/special.R
+++ b/samples/client/petstore/R/R/special.R
@@ -257,3 +257,4 @@ Special <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/tag.R b/samples/client/petstore/R/R/tag.R
index e0cff8390fe..871a0a11811 100644
--- a/samples/client/petstore/R/R/tag.R
+++ b/samples/client/petstore/R/R/tag.R
@@ -165,3 +165,4 @@ Tag <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/update_pet_request.R b/samples/client/petstore/R/R/update_pet_request.R
index fd573b5a8e3..b5e78e331bf 100644
--- a/samples/client/petstore/R/R/update_pet_request.R
+++ b/samples/client/petstore/R/R/update_pet_request.R
@@ -166,3 +166,4 @@ UpdatePetRequest <- R6::R6Class(
     }
   )
 )
+
diff --git a/samples/client/petstore/R/R/user.R b/samples/client/petstore/R/R/user.R
index e99de33bdfc..bccd1511946 100644
--- a/samples/client/petstore/R/R/user.R
+++ b/samples/client/petstore/R/R/user.R
@@ -303,3 +303,4 @@ User <- R6::R6Class(
     }
   )
 )
+