x = 6; | ^^^^^ cannot assign twice to immutable variable | help: consider making this binding mutable | 2 | let mut x = 5; | +++ For more information about this error, try `rustc error 现在我们已经了解了变量如何工作，让我们看看变量可以拥有的更多数据类型。 42/562Rust 程序设计语言 简体中文版 数据类型 在 Rust 中，每一个值都有一个特定 数据类型（data type），这告诉 Rust 它被指定为何种数 据，以便明确数据处理方式。我们将看到两类数据类型子集：标量（scalar）和复合 （compound）。 记住，Rust 是 静态类型（statically some_string.push_str(", world"); | ^^^^^^^^^^^ `some_string` is a `&` reference, so the data it refers to cannot be borrowed as mutable | help: consider changing this to be a mutable reference

request. See the class definition for HTTPServerRequest for a complete list of attributes. Request data in the formats used by HTML forms will be parsed for you and is made available in methods like get_query_argument the files were uploaded with a form wrapper (i.e. a multipart/form-data Content-Type); if this format was not used the raw uploaded data is available in self.request.body. By default uploaded files are fully content into a web page can lead to security vulnerabilities such as cross-site scripting (XSS). All data that is passed to a template should be escaped to prevent these vulnerabilities. The correct form

request. See the class definition for HTTPServerRequest for a complete list of attributes. Request data in the formats used by HTML forms will be parsed for you and is made available in methods like get_query_argument the files were uploaded with a form wrapper (i.e. a multipart/form-data Content-Type); if this format was not used the raw uploaded data is available in self.request.body. By default uploaded files are fully content into a web page can lead to security vulnerabilities such as cross-site scripting (XSS). All data that is passed to a template should be escaped to prevent these vulnerabilities. The correct form