diff --git a/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml b/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
index 2c5ad0483fb..73022c251f9 100644
--- a/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/rust/petstore.yaml
@@ -566,7 +566,7 @@ paths:
           description: User not found
       security:
         - api_key: []
-  '/fake/user/{username}':
+  '/fake/user/{user-name}':
     get:
       tags:
         - fake
@@ -574,7 +574,7 @@ paths:
       description: ''
       operationId: test_nullable_required_param
       parameters:
-        - name: username
+        - name: user-name
           in: path
           description: The name that needs to be fetched. Use user1 for testing.
           required: true
diff --git a/samples/client/petstore/rust/hyper/petstore/README.md b/samples/client/petstore/rust/hyper/petstore/README.md
index 01dbccefa41..2634dbc0941 100644
--- a/samples/client/petstore/rust/hyper/petstore/README.md
+++ b/samples/client/petstore/rust/hyper/petstore/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **Get** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **Get** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **Post** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **Delete** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **Get** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md b/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
index df993a82f4b..09041c0cbe0 100644
--- a/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/hyper/petstore/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **Get** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **Get** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
index 80db3f2c9c6..7dfa43037fd 100644
--- a/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/hyper/petstore/src/apis/fake_api.rs
@@ -37,16 +37,16 @@ impl<C: Connect> FakeApiClient<C>
 }
 
 pub trait FakeApi: Send + Sync {
-    fn test_nullable_required_param(&self, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>>;
 }
 
 impl<C: Connect>FakeApi for FakeApiClient<C>
     where C: Clone + std::marker::Send + Sync {
     #[allow(unused_mut)]
-    fn test_nullable_required_param(&self, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
-        let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{username}".to_string())
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>> + Send>> {
+        let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{user_name}".to_string())
         ;
-        req = req.with_path_param("username".to_string(), username.to_string());
+        req = req.with_path_param("user_name".to_string(), user_name.to_string());
         match dummy_required_nullable_param {
             Some(param_value) => { req = req.with_header_param("dummy_required_nullable_param".to_string(), param_value.to_string()); },
             None => { req = req.with_header_param("dummy_required_nullable_param".to_string(), "".to_string()); },
diff --git a/samples/client/petstore/rust/hyper0x/petstore/README.md b/samples/client/petstore/rust/hyper0x/petstore/README.md
index 5a179aee5e3..321c5795e81 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/README.md
+++ b/samples/client/petstore/rust/hyper0x/petstore/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md b/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/hyper0x/petstore/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
index 685b7262fff..51fb1df2665 100644
--- a/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/hyper0x/petstore/src/apis/fake_api.rs
@@ -36,16 +36,16 @@ impl<C: hyper::client::connect::Connect> FakeApiClient<C>
 }
 
 pub trait FakeApi {
-    fn test_nullable_required_param(&self, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>>;
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>>;
 }
 
 impl<C: hyper::client::connect::Connect>FakeApi for FakeApiClient<C>
     where C: Clone + std::marker::Send + Sync {
     #[allow(unused_mut)]
-    fn test_nullable_required_param(&self, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
-        let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{username}".to_string())
+    fn test_nullable_required_param(&self, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Pin<Box<dyn Future<Output = Result<(), Error>>>> {
+        let mut req = __internal_request::Request::new(hyper::Method::GET, "/fake/user/{user_name}".to_string())
         ;
-        req = req.with_path_param("username".to_string(), username.to_string());
+        req = req.with_path_param("user_name".to_string(), user_name.to_string());
         match dummy_required_nullable_param {
             Some(param_value) => { req = req.with_header_param("dummy_required_nullable_param".to_string(), param_value.to_string()); },
             None => { req = req.with_header_param("dummy_required_nullable_param".to_string(), "".to_string()); },
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/README.md b/samples/client/petstore/rust/reqwest-trait/petstore/README.md
index 0d408cc9704..e872cbcac5b 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/README.md
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md b/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
index 72b79b1d60e..0dbbec22aec 100644
--- a/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest-trait/petstore/src/apis/fake_api.rs
@@ -21,7 +21,7 @@ use super::{Error, configuration};
 #[cfg_attr(feature = "mockall", automock)]
 #[async_trait]
 pub trait FakeApi: Send + Sync {
-    async fn test_nullable_required_param<'username, 'dummy_required_nullable_param, 'uppercase>(&self, username: &'username str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>) -> Result<(), Error<TestNullableRequiredParamError>>;
+    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'uppercase>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>) -> Result<(), Error<TestNullableRequiredParamError>>;
 }
 
 pub struct FakeApiClient {
@@ -39,12 +39,12 @@ impl FakeApiClient {
 #[async_trait]
 impl FakeApi for FakeApiClient {
     /// 
-    async fn test_nullable_required_param<'username, 'dummy_required_nullable_param, 'uppercase>(&self, username: &'username str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+    async fn test_nullable_required_param<'user_name, 'dummy_required_nullable_param, 'uppercase>(&self, user_name: &'user_name str, dummy_required_nullable_param: Option<&'dummy_required_nullable_param str>, uppercase: Option<&'uppercase str>) -> Result<(), Error<TestNullableRequiredParamError>> {
         let local_var_configuration = &self.configuration;
 
         let local_var_client = &local_var_configuration.client;
 
-        let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+        let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
         let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
         if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md b/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
index d00cc8cfd2f..eee50830622 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
index f93b447840d..5a06ed6f119 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-middleware/src/apis/fake_api.rs
@@ -18,7 +18,7 @@ use super::{Error, configuration};
 #[derive(Clone, Debug)]
 pub struct TestNullableRequiredParamParams {
     /// The name that needs to be fetched. Use user1 for testing.
-    pub username: String,
+    pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
     /// To test parameter names in upper case
@@ -49,14 +49,14 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     let local_var_configuration = configuration;
 
     // unbox the parameters
-    let username = params.username;
+    let user_name = params.user_name;
     let dummy_required_nullable_param = params.dummy_required_nullable_param;
     let uppercase = params.uppercase;
 
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
index 987a3bb82fa..58a099a8dcc 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
index f93b447840d..5a06ed6f119 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async-tokensource/src/apis/fake_api.rs
@@ -18,7 +18,7 @@ use super::{Error, configuration};
 #[derive(Clone, Debug)]
 pub struct TestNullableRequiredParamParams {
     /// The name that needs to be fetched. Use user1 for testing.
-    pub username: String,
+    pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
     /// To test parameter names in upper case
@@ -49,14 +49,14 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     let local_var_configuration = configuration;
 
     // unbox the parameters
-    let username = params.username;
+    let user_name = params.user_name;
     let dummy_required_nullable_param = params.dummy_required_nullable_param;
     let uppercase = params.uppercase;
 
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/README.md b/samples/client/petstore/rust/reqwest/petstore-async/README.md
index 3fe9acab678..d999629f2c3 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-async/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
index f93b447840d..5a06ed6f119 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/fake_api.rs
@@ -18,7 +18,7 @@ use super::{Error, configuration};
 #[derive(Clone, Debug)]
 pub struct TestNullableRequiredParamParams {
     /// The name that needs to be fetched. Use user1 for testing.
-    pub username: String,
+    pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
     /// To test parameter names in upper case
@@ -49,14 +49,14 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     let local_var_configuration = configuration;
 
     // unbox the parameters
-    let username = params.username;
+    let user_name = params.user_name;
     let dummy_required_nullable_param = params.dummy_required_nullable_param;
     let uppercase = params.uppercase;
 
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md b/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
index 311391cb60f..62eba5de49c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
index f93b447840d..5a06ed6f119 100644
--- a/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-avoid-box/src/apis/fake_api.rs
@@ -18,7 +18,7 @@ use super::{Error, configuration};
 #[derive(Clone, Debug)]
 pub struct TestNullableRequiredParamParams {
     /// The name that needs to be fetched. Use user1 for testing.
-    pub username: String,
+    pub user_name: String,
     /// To test nullable required parameters
     pub dummy_required_nullable_param: Option<String>,
     /// To test parameter names in upper case
@@ -49,14 +49,14 @@ pub async fn test_nullable_required_param(configuration: &configuration::Configu
     let local_var_configuration = configuration;
 
     // unbox the parameters
-    let username = params.username;
+    let user_name = params.user_name;
     let dummy_required_nullable_param = params.dummy_required_nullable_param;
     let uppercase = params.uppercase;
 
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
index 142ffa567ef..194b455d1d5 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
index 24339cb769a..3f39f065eb1 100644
--- a/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-awsv4signature/src/apis/fake_api.rs
@@ -26,12 +26,12 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     let local_var_configuration = configuration;
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
index 89579250342..dd57f463f69 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
index 24339cb769a..3f39f065eb1 100644
--- a/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-model-name-prefix/src/apis/fake_api.rs
@@ -26,12 +26,12 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     let local_var_configuration = configuration;
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {
diff --git a/samples/client/petstore/rust/reqwest/petstore/README.md b/samples/client/petstore/rust/reqwest/petstore/README.md
index 0d408cc9704..e872cbcac5b 100644
--- a/samples/client/petstore/rust/reqwest/petstore/README.md
+++ b/samples/client/petstore/rust/reqwest/petstore/README.md
@@ -26,7 +26,7 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
-*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+*FakeApi* | [**test_nullable_required_param**](docs/FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 *PetApi* | [**add_pet**](docs/PetApi.md#add_pet) | **POST** /pet | Add a new pet to the store
 *PetApi* | [**delete_pet**](docs/PetApi.md#delete_pet) | **DELETE** /pet/{petId} | Deletes a pet
 *PetApi* | [**find_pets_by_status**](docs/PetApi.md#find_pets_by_status) | **GET** /pet/findByStatus | Finds Pets by status
diff --git a/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
index 55bf612aa21..7fd65038188 100644
--- a/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
+++ b/samples/client/petstore/rust/reqwest/petstore/docs/FakeApi.md
@@ -4,13 +4,13 @@ All URIs are relative to *http://petstore.swagger.io/v2*
 
 Method | HTTP request | Description
 ------------- | ------------- | -------------
-[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{username} | To test nullable required parameters
+[**test_nullable_required_param**](FakeApi.md#test_nullable_required_param) | **GET** /fake/user/{user_name} | To test nullable required parameters
 
 
 
 ## test_nullable_required_param
 
-> test_nullable_required_param(username, dummy_required_nullable_param, uppercase)
+> test_nullable_required_param(user_name, dummy_required_nullable_param, uppercase)
 To test nullable required parameters
 
 
@@ -20,7 +20,7 @@ To test nullable required parameters
 
 Name | Type | Description  | Required | Notes
 ------------- | ------------- | ------------- | ------------- | -------------
-**username** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
+**user_name** | **String** | The name that needs to be fetched. Use user1 for testing. | [required] |
 **dummy_required_nullable_param** | Option<**String**> | To test nullable required parameters | [required] |
 **uppercase** | Option<**String**> | To test parameter names in upper case |  |
 
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
index 24339cb769a..3f39f065eb1 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/fake_api.rs
@@ -26,12 +26,12 @@ pub enum TestNullableRequiredParamError {
 
 
 /// 
-pub fn test_nullable_required_param(configuration: &configuration::Configuration, username: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
+pub fn test_nullable_required_param(configuration: &configuration::Configuration, user_name: &str, dummy_required_nullable_param: Option<&str>, uppercase: Option<&str>) -> Result<(), Error<TestNullableRequiredParamError>> {
     let local_var_configuration = configuration;
 
     let local_var_client = &local_var_configuration.client;
 
-    let local_var_uri_str = format!("{}/fake/user/{username}", local_var_configuration.base_path, username=crate::apis::urlencode(username));
+    let local_var_uri_str = format!("{}/fake/user/{user_name}", local_var_configuration.base_path, user_name=crate::apis::urlencode(user_name));
     let mut local_var_req_builder = local_var_client.request(reqwest::Method::GET, local_var_uri_str.as_str());
 
     if let Some(ref local_var_user_agent) = local_var_configuration.user_agent {