use, super, self

A module can bring symbols from another module into scope with use. You will typically see something like this at the top of each module:

# // Copyright 2022 Google LLC
# // SPDX-License-Identifier: Apache-2.0
#
use std::collections::HashSet;
use std::process::abort;

Paths

Paths are resolved as follows:

1. As a relative path:

   • foo or self::foo refers to foo in the current module,
   • super::foo refers to foo in the parent module.

2. As an absolute path:

   • crate::foo refers to foo in the root of the current crate,
   • bar::foo refers to foo in the bar crate.

• It is common to "re-export" symbols at a shorter path. For example, the top-level lib.rs in a crate might have

  rust,ignoreCopy

  # // Copyright 2022 Google LLC
  # // SPDX-License-Identifier: Apache-2.0
  #
  mod storage;
  
  pub use storage::disk::DiskStorage;
  pub use storage::network::NetworkStorage;
  

  making DiskStorage and NetworkStorage available to other crates with a convenient, short path.

• For the most part, only items that appear in a module need to be use'd. However, a trait must be in scope to call any methods on that trait, even if a type implementing that trait is already in scope. For example, to use the read_to_string method on a type implementing the Read trait, you need to use std::io::Read.

• The use statement can have a wildcard: use std::io::*. This is discouraged because it is not clear which items are imported, and those might change over time.