Cargo 无法找到一个 crate。

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英文:

Cargo is unable to find a crate

问题

我有以下的目录结构在我的Rust项目中:

borrowing
   |
   |-------src
   |        |-------borrow.rs
   |        |-------lib.rs
   | 
   |-------Cargo.toml
   |-------main.rs 

borrow.rs

pub fn simple_borrow() {
    let _a = 10;
    let _b = 20;
    let _b = _a;
    println!("a:{}, b: {}", _a, _b);
}

lib.rs

mod borrow;

main.rs

use borrow;

fn main()
{
    borrow::simple_borrow();
}

Cargo.toml

[package]
name = "borrower"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

[[bin]]
name="borrowery"
path="main.rs"

上述代码给我返回以下错误:

C:\git\Rust examples\borrowing>cargo run
   Compiling borrower v0.1.0 (C:\git\Rust examples\borrowing)
warning: function `simple_borrow` is never used
 --> src\borrow.rs:1:8
  |
1 | pub fn simple_borrow() {
  |        ^^^^^^^^^^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: `borrower` (lib) generated 1 warning
error[E0432]: unresolved import `borrow`
 --> main.rs:1:5
  |
1 | use borrow;
  |     ^^^^^^ no external crate `borrow`
  |
help: consider importing one of these items instead
  |
1 | use core::borrow;
  |     ~~~~~~~~~~~~~
1 | use std::borrow;
  |     ~~~~~~~~~~~~

For more information about this error, try `rustc --explain E0432`.
error: could not compile `borrower` due to previous error

C:\git\Rust examples\borrowing>

我如何解决这个错误?

英文:

I have the following directory structure in my Rust project:

borrowing
   |
   |-------src
   |        |-------borrow.rs
   |        |-------lib.rs
   | 
   |-------Cargo.toml
   |-------main.rs 

borrow.rs

pub fn simple_borrow() {
    let _a = 10;
    let _b = 20;
    let _b = _a;
    println!("a:{}, b: {}", _a, _b);
}

lib.rs

mod borrow;

main.rs

use borrow;

fn main()
{
    borrow::simple_borrow();
}

Cargo.toml

[package]
name = "borrower"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

[[bin]]
name="borrowery"
path="main.rs"

The above is giving me the following error:

C:\git\Rust examples\borrowing>cargo run
   Compiling borrower v0.1.0 (C:\git\Rust examples\borrowing)
warning: function `simple_borrow` is never used
 --> src\borrow.rs:1:8
  |
1 | pub fn simple_borrow() {
  |        ^^^^^^^^^^^^^
  |
  = note: `#[warn(dead_code)]` on by default

warning: `borrower` (lib) generated 1 warning
error[E0432]: unresolved import `borrow`
 --> main.rs:1:5
  |
1 | use borrow;
  |     ^^^^^^ no external crate `borrow`
  |
help: consider importing one of these items instead
  |
1 | use core::borrow;
  |     ~~~~~~~~~~~~~
1 | use std::borrow;
  |     ~~~~~~~~~~~~

For more information about this error, try `rustc --explain E0432`.
error: could not compile `borrower` due to previous error

C:\git\Rust examples\borrowing>

How can I resolve the error?

答案1

得分: 2

Your code has 2 errors, the first is you're using the wrong path for the module, src/lib.rs and every binary, in your case main.rs are in different crates, therefore instead of the relative path borrow you have to use the full path, including the crate name, which defaults to the packages name: borrower::borrow:

use borrower::borrow;

Then Rust will tell you that the module borrow is private and you can't use it. To make it public you can simply use the pub keyword in front of the module declaration in src/lib.rs:

pub mod borrow;
英文:

Your code has 2 errors, the first is you're using the wrong path for the module, src/lib.rs and every binary, in your case main.rs are in different crates, therefore instead of the relative path borrow you have to use the full path, including the crate name, which defaults to the packages name: borrower::borrow:

use borrower::borrow;

Then Rust will tell you that the module borrow is private and you can't use it. To make it public you can simply use the pub keyword in front of the module declaration in src/lib.rs:

pub mod borrow;

huangapple
  • 本文由 发表于 2023年3月7日 00:36:03
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