Listing 12-14: use minigrep; instead of extern crate minigrep; results in error

[jvivian]

I'm following the current live version of the Rust book (master on Github) and encountered the following issue:

Listing 12-14 states to use use minigrep; "... to bring the library crate into the binary crate". Yet when I do that I get the following compile errors when calling cargo run:

error[E0432]: unresolved import `minigrep`                                                                                                                                
 --> src/main.rs:2:5                                                                                                                                                      
  |                                                                                                                                                                       
2 | use minigrep;                                                                                                                                                         
  |     ^^^^^^^^ no `minigrep` in the root                                                                                                                                
                                                                                                                                                                          
error[E0433]: failed to resolve. Use of undeclared type or module `Config`                                                                                                
  --> src/main.rs:11:18                                                                                                                                                   
   |                                                                                                                                                                      
11 |     let config = Config::new(&args).unwrap_or_else(|err| {                                                                                                           
   |                  ^^^^^^ Use of undeclared type or module `Config`    

If I change use minigrep; to extern crate minigrep; the problem goes away.

I'd be happy to open a pull request if this is a legitimate bug.

[anuj1102]

I'm running into the same issue as well, and the fix above worked for me.

[carols10cents]

@jvivian and @anuj1102 Do you have edition="2018" in your Cargo.toml and are you using Rust 1.31.0? The current version of the book assumes 2018 Edition Rust.

[jvivian]

Hi @carols10cents,

Thank you for the reply — I see now that the book is in lockstep with the latest release of Rust and the version I installed last week (1.30.1) doesn't include the edition="2018" in Cargo.toml. I updated via rustup update and added edition = "2018" which resolved my issue. Thank you very much! I'll go ahead and close this.

[carols10cents]

Yep, the edition switchover is a bit confusing right now. Glad this solved your problem!

…

On Mon, Dec 10, 2018, 12:54 PM John Vivian ***@***.*** wrote: Hi @carols10cents <https://github.com/carols10cents>, Thank you for the reply — I see now that the book is in lockstep with the latest release of Rust and the version I installed last week (1.30.1) doesn't include the edition="2018" in Cargo.toml. I updated via rustup update and added edition = "2018" which resolved my issue. Thank you very much! I'll go ahead and close this. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1676 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAL1Ul1JiRUSzMA2ZSdy8SBw_AVaqhVKks5u3p_JgaJpZM4ZKYV4> .

[taiprogramer]

I try to re-create project with --lib (cargo new minigrep --lib), react new main.rs file and copy everything. Now, It's work.
Hope this useful to other!

[TylerBrock]

In case anyone else stumbles upon this in the future the correct answer is actually to run cargo clean. I found that I had edition = "2018" but the incremental build process gets confused when you move the code from main.rs to lib.rs so you need to clear them out.

[gitgitcode]

in my case version is
cargo 1.60.0 (d1fd9fe2c 2022-03-01)
rustc 1.60.0 (7737e0b5c 2022-04-04)
i just edit once to edition = "2018" it's solved.
then turn back to edition = "2021" it's ok.
at last i also run cargo clean