diff --git a/modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache b/modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache
index 4e7c63fe5ccf..f63ece5c942c 100644
--- a/modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache
+++ b/modules/openapi-generator/src/main/resources/rust/reqwest/api.mustache
@@ -1,7 +1,7 @@
 {{>partial_header}}
 #[allow(unused_imports)]
 use std::rc::Rc;
-use std::borrow::Borrow;
+{{^supportAsync}}use std::borrow::Borrow;{{/supportAsync}}
 use std::option::Option;
 
 use reqwest;
@@ -49,10 +49,10 @@ pub trait {{{classname}}} {
 {{#operations}}
 {{#operation}}
     {{#vendorExtensions.x-group-parameters}}
-    fn {{{operationId}}}(&self{{#allParams}}{{#-first}}, params: {{{operationIdCamelCase}}}Params{{/-first}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error>;
+    fn {{{operationId}}}(&self{{#allParams}}{{#-first}}, params: {{{operationIdCamelCase}}}Params{{/-first}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error<serde_json::Value>>;
     {{/vendorExtensions.x-group-parameters}}
     {{^vendorExtensions.x-group-parameters}}
-    fn {{{operationId}}}(&self, {{#allParams}}{{{paramName}}}: {{^required}}Option<{{/required}}{{#required}}{{#isNullable}}Option<{{/isNullable}}{{/required}}{{#isString}}&str{{/isString}}{{#isUuid}}&str{{/isUuid}}{{^isString}}{{^isUuid}}{{^isPrimitiveType}}{{^isContainer}}crate::models::{{/isContainer}}{{/isPrimitiveType}}{{{dataType}}}{{/isUuid}}{{/isString}}{{^required}}>{{/required}}{{#required}}{{#isNullable}}>{{/isNullable}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error>;
+    fn {{{operationId}}}(&self, {{#allParams}}{{{paramName}}}: {{^required}}Option<{{/required}}{{#required}}{{#isNullable}}Option<{{/isNullable}}{{/required}}{{#isString}}&str{{/isString}}{{#isUuid}}&str{{/isUuid}}{{^isString}}{{^isUuid}}{{^isPrimitiveType}}{{^isContainer}}crate::models::{{/isContainer}}{{/isPrimitiveType}}{{{dataType}}}{{/isUuid}}{{/isString}}{{^required}}>{{/required}}{{#required}}{{#isNullable}}>{{/isNullable}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error<serde_json::Value>>;
     {{/vendorExtensions.x-group-parameters}}
 {{/operation}}
 {{/operations}}
@@ -63,7 +63,7 @@ impl {{{classname}}} for {{{classname}}}Client {
 {{#operations}}
 {{#operation}}
     {{#vendorExtensions.x-group-parameters}}
-    {{#supportAsync}}pub async {{/supportAsync}}fn {{{operationId}}}({{^supportAsync}}&self{{/supportAsync}}{{#supportAsync}}configuration: &configuration::Configuration{{/supportAsync}}{{#allParams}}{{#-first}}, params: {{{operationIdCamelCase}}}Params{{/-first}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error> {
+    {{#supportAsync}}pub async {{/supportAsync}}fn {{{operationId}}}({{^supportAsync}}&self{{/supportAsync}}{{#supportAsync}}configuration: &configuration::Configuration{{/supportAsync}}{{#allParams}}{{#-first}}, params: {{{operationIdCamelCase}}}Params{{/-first}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error<serde_json::Value>> {
         // unbox the parameters
         {{#allParams}}
         let {{paramName}} = params.{{paramName}};
@@ -71,7 +71,7 @@ impl {{{classname}}} for {{{classname}}}Client {
 
     {{/vendorExtensions.x-group-parameters}}
     {{^vendorExtensions.x-group-parameters}}
-    {{#supportAsync}}pub async {{/supportAsync}}fn {{{operationId}}}({{^supportAsync}}&self{{/supportAsync}}{{#supportAsync}}configuration: &configuration::Configuration{{/supportAsync}}, {{#allParams}}{{{paramName}}}: {{^required}}Option<{{/required}}{{#required}}{{#isNullable}}Option<{{/isNullable}}{{/required}}{{#isString}}&str{{/isString}}{{#isUuid}}&str{{/isUuid}}{{^isString}}{{^isUuid}}{{^isPrimitiveType}}{{^isContainer}}crate::models::{{/isContainer}}{{/isPrimitiveType}}{{{dataType}}}{{/isUuid}}{{/isString}}{{^required}}>{{/required}}{{#required}}{{#isNullable}}>{{/isNullable}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error> {
+    {{#supportAsync}}pub async {{/supportAsync}}fn {{{operationId}}}({{^supportAsync}}&self{{/supportAsync}}{{#supportAsync}}configuration: &configuration::Configuration{{/supportAsync}}, {{#allParams}}{{{paramName}}}: {{^required}}Option<{{/required}}{{#required}}{{#isNullable}}Option<{{/isNullable}}{{/required}}{{#isString}}&str{{/isString}}{{#isUuid}}&str{{/isUuid}}{{^isString}}{{^isUuid}}{{^isPrimitiveType}}{{^isContainer}}crate::models::{{/isContainer}}{{/isPrimitiveType}}{{{dataType}}}{{/isUuid}}{{/isString}}{{^required}}>{{/required}}{{#required}}{{#isNullable}}>{{/isNullable}}{{/required}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) -> Result<{{^returnType}}(){{/returnType}}{{#returnType}}{{{returnType}}}{{/returnType}}, Error<serde_json::Value>> {
     {{/vendorExtensions.x-group-parameters}}
         {{^supportAsync}}
         let configuration: &configuration::Configuration = self.configuration.borrow();
@@ -263,7 +263,7 @@ impl {{{classname}}} for {{{classname}}}Client {
         {{/hasBodyParam}}
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req){{#supportAsync}}.await{{/supportAsync}}?;
+        let {{^supportAsync}}mut {{/supportAsync}}resp = client.execute(req){{#supportAsync}}.await{{/supportAsync}}?;
         if resp.status().is_success() {
             {{^returnType}}
             Ok(())
diff --git a/modules/openapi-generator/src/main/resources/rust/reqwest/api_mod.mustache b/modules/openapi-generator/src/main/resources/rust/reqwest/api_mod.mustache
index f9aba13baf9f..991df72e4e08 100644
--- a/modules/openapi-generator/src/main/resources/rust/reqwest/api_mod.mustache
+++ b/modules/openapi-generator/src/main/resources/rust/reqwest/api_mod.mustache
@@ -2,33 +2,33 @@ use reqwest;
 use serde_json;
 
 #[derive(Debug, Clone)]
-pub struct ResponseErrorContent {
+pub struct ResponseErrorContent<T> {
     pub status: reqwest::StatusCode,
     pub content: String,
-    pub entity: Option<serde_json::Value>,
+    pub entity: Option<T>,
 }
 
 #[derive(Debug)]
-pub enum Error {
+pub enum Error<T> {
     Reqwest(reqwest::Error),
     Serde(serde_json::Error),
     Io(std::io::Error),
-    ResponseError(ResponseErrorContent),
+    ResponseError(ResponseErrorContent<T>),
 }
 
-impl From<reqwest::Error> for Error {
+impl <T> From<reqwest::Error> for Error<T> {
     fn from(e: reqwest::Error) -> Self {
         Error::Reqwest(e)
     }
 }
 
-impl From<serde_json::Error> for Error {
+impl <T> From<serde_json::Error> for Error<T> {
     fn from(e: serde_json::Error) -> Self {
         Error::Serde(e)
     }
 }
 
-impl From<std::io::Error> for Error {
+impl <T> From<std::io::Error> for Error<T> {
     fn from(e: std::io::Error) -> Self {
         Error::Io(e)
     }
diff --git a/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/default_api.rs b/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/default_api.rs
index e20a276940ae..d7a1750eb71a 100644
--- a/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/default_api.rs
+++ b/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/default_api.rs
@@ -31,11 +31,11 @@ impl DefaultApiClient {
 
 
 pub trait DefaultApi {
-    fn fileresponsetest(&self, ) -> Result<std::path::PathBuf, Error>;
+    fn fileresponsetest(&self, ) -> Result<std::path::PathBuf, Error<serde_json::Value>>;
 }
 
 impl DefaultApi for DefaultApiClient {
-    fn fileresponsetest(&self, ) -> Result<std::path::PathBuf, Error> {
+    fn fileresponsetest(&self, ) -> Result<std::path::PathBuf, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
diff --git a/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/mod.rs b/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/mod.rs
index 68e16d25dd77..d7bf6b5967d8 100644
--- a/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/mod.rs
+++ b/samples/client/petstore/rust/reqwest/fileResponseTest/src/apis/mod.rs
@@ -2,33 +2,33 @@ use reqwest;
 use serde_json;
 
 #[derive(Debug, Clone)]
-pub struct ResponseErrorContent {
+pub struct ResponseErrorContent<T> {
     pub status: reqwest::StatusCode,
     pub content: String,
-    pub entity: Option<serde_json::Value>,
+    pub entity: Option<T>,
 }
 
 #[derive(Debug)]
-pub enum Error {
+pub enum Error<T> {
     Reqwest(reqwest::Error),
     Serde(serde_json::Error),
     Io(std::io::Error),
-    ResponseError(ResponseErrorContent),
+    ResponseError(ResponseErrorContent<T>),
 }
 
-impl From<reqwest::Error> for Error {
+impl <T> From<reqwest::Error> for Error<T> {
     fn from(e: reqwest::Error) -> Self {
         Error::Reqwest(e)
     }
 }
 
-impl From<serde_json::Error> for Error {
+impl <T> From<serde_json::Error> for Error<T> {
     fn from(e: serde_json::Error) -> Self {
         Error::Serde(e)
     }
 }
 
-impl From<std::io::Error> for Error {
+impl <T> From<std::io::Error> for Error<T> {
     fn from(e: std::io::Error) -> Self {
         Error::Io(e)
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/mod.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/mod.rs
index d5094fdc85d9..a48a5cb9a3bd 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/mod.rs
@@ -2,33 +2,33 @@ use reqwest;
 use serde_json;
 
 #[derive(Debug, Clone)]
-pub struct ResponseErrorContent {
+pub struct ResponseErrorContent<T> {
     pub status: reqwest::StatusCode,
     pub content: String,
-    pub entity: Option<serde_json::Value>,
+    pub entity: Option<T>,
 }
 
 #[derive(Debug)]
-pub enum Error {
+pub enum Error<T> {
     Reqwest(reqwest::Error),
     Serde(serde_json::Error),
     Io(std::io::Error),
-    ResponseError(ResponseErrorContent),
+    ResponseError(ResponseErrorContent<T>),
 }
 
-impl From<reqwest::Error> for Error {
+impl <T> From<reqwest::Error> for Error<T> {
     fn from(e: reqwest::Error) -> Self {
         Error::Reqwest(e)
     }
 }
 
-impl From<serde_json::Error> for Error {
+impl <T> From<serde_json::Error> for Error<T> {
     fn from(e: serde_json::Error) -> Self {
         Error::Serde(e)
     }
 }
 
-impl From<std::io::Error> for Error {
+impl <T> From<std::io::Error> for Error<T> {
     fn from(e: std::io::Error) -> Self {
         Error::Io(e)
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/pet_api.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/pet_api.rs
index 7611ba5eb9bf..0a071213099e 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/pet_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/pet_api.rs
@@ -10,7 +10,7 @@
 
 #[allow(unused_imports)]
 use std::rc::Rc;
-use std::borrow::Borrow;
+
 use std::option::Option;
 
 use reqwest;
@@ -18,7 +18,7 @@ use reqwest;
 use super::{Error, configuration};
 
 
-    pub async fn add_pet(configuration: &configuration::Configuration, body: crate::models::Pet) -> Result<(), Error> {
+    pub async fn add_pet(configuration: &configuration::Configuration, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet", configuration.base_path);
@@ -33,7 +33,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -45,7 +45,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn delete_pet(configuration: &configuration::Configuration, pet_id: i64, api_key: Option<&str>) -> Result<(), Error> {
+    pub async fn delete_pet(configuration: &configuration::Configuration, pet_id: i64, api_key: Option<&str>) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/{petId}", configuration.base_path, petId=pet_id);
@@ -62,7 +62,7 @@ use super::{Error, configuration};
         };
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -74,7 +74,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn find_pets_by_status(configuration: &configuration::Configuration, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error> {
+    pub async fn find_pets_by_status(configuration: &configuration::Configuration, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/findByStatus", configuration.base_path);
@@ -89,7 +89,7 @@ use super::{Error, configuration};
         };
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<Vec<crate::models::Pet>>().await?)
         } else {
@@ -101,7 +101,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn find_pets_by_tags(configuration: &configuration::Configuration, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error> {
+    pub async fn find_pets_by_tags(configuration: &configuration::Configuration, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/findByTags", configuration.base_path);
@@ -116,7 +116,7 @@ use super::{Error, configuration};
         };
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<Vec<crate::models::Pet>>().await?)
         } else {
@@ -128,7 +128,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn get_pet_by_id(configuration: &configuration::Configuration, pet_id: i64) -> Result<crate::models::Pet, Error> {
+    pub async fn get_pet_by_id(configuration: &configuration::Configuration, pet_id: i64) -> Result<crate::models::Pet, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/{petId}", configuration.base_path, petId=pet_id);
@@ -147,7 +147,7 @@ use super::{Error, configuration};
         };
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<crate::models::Pet>().await?)
         } else {
@@ -159,7 +159,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn update_pet(configuration: &configuration::Configuration, body: crate::models::Pet) -> Result<(), Error> {
+    pub async fn update_pet(configuration: &configuration::Configuration, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet", configuration.base_path);
@@ -174,7 +174,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -186,7 +186,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn update_pet_with_form(configuration: &configuration::Configuration, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error> {
+    pub async fn update_pet_with_form(configuration: &configuration::Configuration, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/{petId}", configuration.base_path, petId=pet_id);
@@ -208,7 +208,7 @@ use super::{Error, configuration};
         req_builder = req_builder.form(&form_params);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -220,7 +220,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn upload_file(configuration: &configuration::Configuration, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error> {
+    pub async fn upload_file(configuration: &configuration::Configuration, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/pet/{petId}/uploadImage", configuration.base_path, petId=pet_id);
@@ -240,7 +240,7 @@ use super::{Error, configuration};
         req_builder = req_builder.multipart(form);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<crate::models::ApiResponse>().await?)
         } else {
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/store_api.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/store_api.rs
index fd47da210aa7..84243ee179bc 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/store_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/store_api.rs
@@ -10,7 +10,7 @@
 
 #[allow(unused_imports)]
 use std::rc::Rc;
-use std::borrow::Borrow;
+
 use std::option::Option;
 
 use reqwest;
@@ -18,7 +18,7 @@ use reqwest;
 use super::{Error, configuration};
 
 
-    pub async fn delete_order(configuration: &configuration::Configuration, order_id: &str) -> Result<(), Error> {
+    pub async fn delete_order(configuration: &configuration::Configuration, order_id: &str) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/store/order/{orderId}", configuration.base_path, orderId=crate::apis::urlencode(order_id));
@@ -29,7 +29,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -41,7 +41,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn get_inventory(configuration: &configuration::Configuration, ) -> Result<::std::collections::HashMap<String, i32>, Error> {
+    pub async fn get_inventory(configuration: &configuration::Configuration, ) -> Result<::std::collections::HashMap<String, i32>, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/store/inventory", configuration.base_path);
@@ -60,7 +60,7 @@ use super::{Error, configuration};
         };
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<::std::collections::HashMap<String, i32>>().await?)
         } else {
@@ -72,7 +72,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn get_order_by_id(configuration: &configuration::Configuration, order_id: i64) -> Result<crate::models::Order, Error> {
+    pub async fn get_order_by_id(configuration: &configuration::Configuration, order_id: i64) -> Result<crate::models::Order, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/store/order/{orderId}", configuration.base_path, orderId=order_id);
@@ -83,7 +83,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<crate::models::Order>().await?)
         } else {
@@ -95,7 +95,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn place_order(configuration: &configuration::Configuration, body: crate::models::Order) -> Result<crate::models::Order, Error> {
+    pub async fn place_order(configuration: &configuration::Configuration, body: crate::models::Order) -> Result<crate::models::Order, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/store/order", configuration.base_path);
@@ -107,7 +107,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<crate::models::Order>().await?)
         } else {
diff --git a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/user_api.rs b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/user_api.rs
index 4f3c5b46cd94..e5d2f703750c 100644
--- a/samples/client/petstore/rust/reqwest/petstore-async/src/apis/user_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore-async/src/apis/user_api.rs
@@ -10,7 +10,7 @@
 
 #[allow(unused_imports)]
 use std::rc::Rc;
-use std::borrow::Borrow;
+
 use std::option::Option;
 
 use reqwest;
@@ -18,7 +18,7 @@ use reqwest;
 use super::{Error, configuration};
 
 
-    pub async fn create_user(configuration: &configuration::Configuration, body: crate::models::User) -> Result<(), Error> {
+    pub async fn create_user(configuration: &configuration::Configuration, body: crate::models::User) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user", configuration.base_path);
@@ -30,7 +30,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -42,7 +42,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn create_users_with_array_input(configuration: &configuration::Configuration, body: Vec<crate::models::User>) -> Result<(), Error> {
+    pub async fn create_users_with_array_input(configuration: &configuration::Configuration, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/createWithArray", configuration.base_path);
@@ -54,7 +54,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -66,7 +66,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn create_users_with_list_input(configuration: &configuration::Configuration, body: Vec<crate::models::User>) -> Result<(), Error> {
+    pub async fn create_users_with_list_input(configuration: &configuration::Configuration, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/createWithList", configuration.base_path);
@@ -78,7 +78,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -90,7 +90,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn delete_user(configuration: &configuration::Configuration, username: &str) -> Result<(), Error> {
+    pub async fn delete_user(configuration: &configuration::Configuration, username: &str) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/{username}", configuration.base_path, username=crate::apis::urlencode(username));
@@ -101,7 +101,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -113,7 +113,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn get_user_by_name(configuration: &configuration::Configuration, username: &str) -> Result<crate::models::User, Error> {
+    pub async fn get_user_by_name(configuration: &configuration::Configuration, username: &str) -> Result<crate::models::User, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/{username}", configuration.base_path, username=crate::apis::urlencode(username));
@@ -124,7 +124,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<crate::models::User>().await?)
         } else {
@@ -136,7 +136,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn login_user(configuration: &configuration::Configuration, username: &str, password: &str) -> Result<String, Error> {
+    pub async fn login_user(configuration: &configuration::Configuration, username: &str, password: &str) -> Result<String, Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/login", configuration.base_path);
@@ -149,7 +149,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(resp.json::<String>().await?)
         } else {
@@ -161,7 +161,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn logout_user(configuration: &configuration::Configuration, ) -> Result<(), Error> {
+    pub async fn logout_user(configuration: &configuration::Configuration, ) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/logout", configuration.base_path);
@@ -172,7 +172,7 @@ use super::{Error, configuration};
         }
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
@@ -184,7 +184,7 @@ use super::{Error, configuration};
         }
     }
 
-    pub async fn update_user(configuration: &configuration::Configuration, username: &str, body: crate::models::User) -> Result<(), Error> {
+    pub async fn update_user(configuration: &configuration::Configuration, username: &str, body: crate::models::User) -> Result<(), Error<serde_json::Value>> {
         let client = &configuration.client;
 
         let uri_str = format!("{}/user/{username}", configuration.base_path, username=crate::apis::urlencode(username));
@@ -196,7 +196,7 @@ use super::{Error, configuration};
         req_builder = req_builder.json(&body);
 
         let req = req_builder.build()?;
-        let mut resp = client.execute(req).await?;
+        let resp = client.execute(req).await?;
         if resp.status().is_success() {
             Ok(())
         } else {
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/mod.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/mod.rs
index 5951c1bdd81e..4f25e9c66608 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/mod.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/mod.rs
@@ -2,33 +2,33 @@ use reqwest;
 use serde_json;
 
 #[derive(Debug, Clone)]
-pub struct ResponseErrorContent {
+pub struct ResponseErrorContent<T> {
     pub status: reqwest::StatusCode,
     pub content: String,
-    pub entity: Option<serde_json::Value>,
+    pub entity: Option<T>,
 }
 
 #[derive(Debug)]
-pub enum Error {
+pub enum Error<T> {
     Reqwest(reqwest::Error),
     Serde(serde_json::Error),
     Io(std::io::Error),
-    ResponseError(ResponseErrorContent),
+    ResponseError(ResponseErrorContent<T>),
 }
 
-impl From<reqwest::Error> for Error {
+impl <T> From<reqwest::Error> for Error<T> {
     fn from(e: reqwest::Error) -> Self {
         Error::Reqwest(e)
     }
 }
 
-impl From<serde_json::Error> for Error {
+impl <T> From<serde_json::Error> for Error<T> {
     fn from(e: serde_json::Error) -> Self {
         Error::Serde(e)
     }
 }
 
-impl From<std::io::Error> for Error {
+impl <T> From<std::io::Error> for Error<T> {
     fn from(e: std::io::Error) -> Self {
         Error::Io(e)
     }
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/pet_api.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/pet_api.rs
index 110aea402e92..f956d069827f 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/pet_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/pet_api.rs
@@ -31,18 +31,18 @@ impl PetApiClient {
 
 
 pub trait PetApi {
-    fn add_pet(&self, body: crate::models::Pet) -> Result<(), Error>;
-    fn delete_pet(&self, pet_id: i64, api_key: Option<&str>) -> Result<(), Error>;
-    fn find_pets_by_status(&self, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error>;
-    fn find_pets_by_tags(&self, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error>;
-    fn get_pet_by_id(&self, pet_id: i64) -> Result<crate::models::Pet, Error>;
-    fn update_pet(&self, body: crate::models::Pet) -> Result<(), Error>;
-    fn update_pet_with_form(&self, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error>;
-    fn upload_file(&self, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error>;
+    fn add_pet(&self, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>>;
+    fn delete_pet(&self, pet_id: i64, api_key: Option<&str>) -> Result<(), Error<serde_json::Value>>;
+    fn find_pets_by_status(&self, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>>;
+    fn find_pets_by_tags(&self, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>>;
+    fn get_pet_by_id(&self, pet_id: i64) -> Result<crate::models::Pet, Error<serde_json::Value>>;
+    fn update_pet(&self, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>>;
+    fn update_pet_with_form(&self, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error<serde_json::Value>>;
+    fn upload_file(&self, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error<serde_json::Value>>;
 }
 
 impl PetApi for PetApiClient {
-    fn add_pet(&self, body: crate::models::Pet) -> Result<(), Error> {
+    fn add_pet(&self, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -70,7 +70,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn delete_pet(&self, pet_id: i64, api_key: Option<&str>) -> Result<(), Error> {
+    fn delete_pet(&self, pet_id: i64, api_key: Option<&str>) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -100,7 +100,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn find_pets_by_status(&self, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error> {
+    fn find_pets_by_status(&self, status: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -128,7 +128,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn find_pets_by_tags(&self, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error> {
+    fn find_pets_by_tags(&self, tags: Vec<String>) -> Result<Vec<crate::models::Pet>, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -156,7 +156,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn get_pet_by_id(&self, pet_id: i64) -> Result<crate::models::Pet, Error> {
+    fn get_pet_by_id(&self, pet_id: i64) -> Result<crate::models::Pet, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -188,7 +188,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn update_pet(&self, body: crate::models::Pet) -> Result<(), Error> {
+    fn update_pet(&self, body: crate::models::Pet) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -216,7 +216,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn update_pet_with_form(&self, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error> {
+    fn update_pet_with_form(&self, pet_id: i64, name: Option<&str>, status: Option<&str>) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -251,7 +251,7 @@ impl PetApi for PetApiClient {
         }
     }
 
-    fn upload_file(&self, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error> {
+    fn upload_file(&self, pet_id: i64, additional_metadata: Option<&str>, file: Option<std::path::PathBuf>) -> Result<crate::models::ApiResponse, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/store_api.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/store_api.rs
index 49f625c6e4ab..04bbf3d47711 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/store_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/store_api.rs
@@ -31,14 +31,14 @@ impl StoreApiClient {
 
 
 pub trait StoreApi {
-    fn delete_order(&self, order_id: &str) -> Result<(), Error>;
-    fn get_inventory(&self, ) -> Result<::std::collections::HashMap<String, i32>, Error>;
-    fn get_order_by_id(&self, order_id: i64) -> Result<crate::models::Order, Error>;
-    fn place_order(&self, body: crate::models::Order) -> Result<crate::models::Order, Error>;
+    fn delete_order(&self, order_id: &str) -> Result<(), Error<serde_json::Value>>;
+    fn get_inventory(&self, ) -> Result<::std::collections::HashMap<String, i32>, Error<serde_json::Value>>;
+    fn get_order_by_id(&self, order_id: i64) -> Result<crate::models::Order, Error<serde_json::Value>>;
+    fn place_order(&self, body: crate::models::Order) -> Result<crate::models::Order, Error<serde_json::Value>>;
 }
 
 impl StoreApi for StoreApiClient {
-    fn delete_order(&self, order_id: &str) -> Result<(), Error> {
+    fn delete_order(&self, order_id: &str) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -62,7 +62,7 @@ impl StoreApi for StoreApiClient {
         }
     }
 
-    fn get_inventory(&self, ) -> Result<::std::collections::HashMap<String, i32>, Error> {
+    fn get_inventory(&self, ) -> Result<::std::collections::HashMap<String, i32>, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -94,7 +94,7 @@ impl StoreApi for StoreApiClient {
         }
     }
 
-    fn get_order_by_id(&self, order_id: i64) -> Result<crate::models::Order, Error> {
+    fn get_order_by_id(&self, order_id: i64) -> Result<crate::models::Order, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -118,7 +118,7 @@ impl StoreApi for StoreApiClient {
         }
     }
 
-    fn place_order(&self, body: crate::models::Order) -> Result<crate::models::Order, Error> {
+    fn place_order(&self, body: crate::models::Order) -> Result<crate::models::Order, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
diff --git a/samples/client/petstore/rust/reqwest/petstore/src/apis/user_api.rs b/samples/client/petstore/rust/reqwest/petstore/src/apis/user_api.rs
index 3bb552cd84a4..2e9d76c80e3d 100644
--- a/samples/client/petstore/rust/reqwest/petstore/src/apis/user_api.rs
+++ b/samples/client/petstore/rust/reqwest/petstore/src/apis/user_api.rs
@@ -31,18 +31,18 @@ impl UserApiClient {
 
 
 pub trait UserApi {
-    fn create_user(&self, body: crate::models::User) -> Result<(), Error>;
-    fn create_users_with_array_input(&self, body: Vec<crate::models::User>) -> Result<(), Error>;
-    fn create_users_with_list_input(&self, body: Vec<crate::models::User>) -> Result<(), Error>;
-    fn delete_user(&self, username: &str) -> Result<(), Error>;
-    fn get_user_by_name(&self, username: &str) -> Result<crate::models::User, Error>;
-    fn login_user(&self, username: &str, password: &str) -> Result<String, Error>;
-    fn logout_user(&self, ) -> Result<(), Error>;
-    fn update_user(&self, username: &str, body: crate::models::User) -> Result<(), Error>;
+    fn create_user(&self, body: crate::models::User) -> Result<(), Error<serde_json::Value>>;
+    fn create_users_with_array_input(&self, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>>;
+    fn create_users_with_list_input(&self, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>>;
+    fn delete_user(&self, username: &str) -> Result<(), Error<serde_json::Value>>;
+    fn get_user_by_name(&self, username: &str) -> Result<crate::models::User, Error<serde_json::Value>>;
+    fn login_user(&self, username: &str, password: &str) -> Result<String, Error<serde_json::Value>>;
+    fn logout_user(&self, ) -> Result<(), Error<serde_json::Value>>;
+    fn update_user(&self, username: &str, body: crate::models::User) -> Result<(), Error<serde_json::Value>>;
 }
 
 impl UserApi for UserApiClient {
-    fn create_user(&self, body: crate::models::User) -> Result<(), Error> {
+    fn create_user(&self, body: crate::models::User) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -67,7 +67,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn create_users_with_array_input(&self, body: Vec<crate::models::User>) -> Result<(), Error> {
+    fn create_users_with_array_input(&self, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -92,7 +92,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn create_users_with_list_input(&self, body: Vec<crate::models::User>) -> Result<(), Error> {
+    fn create_users_with_list_input(&self, body: Vec<crate::models::User>) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -117,7 +117,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn delete_user(&self, username: &str) -> Result<(), Error> {
+    fn delete_user(&self, username: &str) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -141,7 +141,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn get_user_by_name(&self, username: &str) -> Result<crate::models::User, Error> {
+    fn get_user_by_name(&self, username: &str) -> Result<crate::models::User, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -165,7 +165,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn login_user(&self, username: &str, password: &str) -> Result<String, Error> {
+    fn login_user(&self, username: &str, password: &str) -> Result<String, Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -191,7 +191,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn logout_user(&self, ) -> Result<(), Error> {
+    fn logout_user(&self, ) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
@@ -215,7 +215,7 @@ impl UserApi for UserApiClient {
         }
     }
 
-    fn update_user(&self, username: &str, body: crate::models::User) -> Result<(), Error> {
+    fn update_user(&self, username: &str, body: crate::models::User) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
diff --git a/samples/client/petstore/rust/reqwest/rust-test/src/apis/default_api.rs b/samples/client/petstore/rust/reqwest/rust-test/src/apis/default_api.rs
index e65d80b22720..24f19aa5a9c6 100644
--- a/samples/client/petstore/rust/reqwest/rust-test/src/apis/default_api.rs
+++ b/samples/client/petstore/rust/reqwest/rust-test/src/apis/default_api.rs
@@ -31,11 +31,11 @@ impl DefaultApiClient {
 
 
 pub trait DefaultApi {
-    fn dummy_get(&self, ) -> Result<(), Error>;
+    fn dummy_get(&self, ) -> Result<(), Error<serde_json::Value>>;
 }
 
 impl DefaultApi for DefaultApiClient {
-    fn dummy_get(&self, ) -> Result<(), Error> {
+    fn dummy_get(&self, ) -> Result<(), Error<serde_json::Value>> {
         let configuration: &configuration::Configuration = self.configuration.borrow();
         let client = &configuration.client;
 
diff --git a/samples/client/petstore/rust/reqwest/rust-test/src/apis/mod.rs b/samples/client/petstore/rust/reqwest/rust-test/src/apis/mod.rs
index 68e16d25dd77..d7bf6b5967d8 100644
--- a/samples/client/petstore/rust/reqwest/rust-test/src/apis/mod.rs
+++ b/samples/client/petstore/rust/reqwest/rust-test/src/apis/mod.rs
@@ -2,33 +2,33 @@ use reqwest;
 use serde_json;
 
 #[derive(Debug, Clone)]
-pub struct ResponseErrorContent {
+pub struct ResponseErrorContent<T> {
     pub status: reqwest::StatusCode,
     pub content: String,
-    pub entity: Option<serde_json::Value>,
+    pub entity: Option<T>,
 }
 
 #[derive(Debug)]
-pub enum Error {
+pub enum Error<T> {
     Reqwest(reqwest::Error),
     Serde(serde_json::Error),
     Io(std::io::Error),
-    ResponseError(ResponseErrorContent),
+    ResponseError(ResponseErrorContent<T>),
 }
 
-impl From<reqwest::Error> for Error {
+impl <T> From<reqwest::Error> for Error<T> {
     fn from(e: reqwest::Error) -> Self {
         Error::Reqwest(e)
     }
 }
 
-impl From<serde_json::Error> for Error {
+impl <T> From<serde_json::Error> for Error<T> {
     fn from(e: serde_json::Error) -> Self {
         Error::Serde(e)
     }
 }
 
-impl From<std::io::Error> for Error {
+impl <T> From<std::io::Error> for Error<T> {
     fn from(e: std::io::Error) -> Self {
         Error::Io(e)
     }