Fixing Private Function Error | Generated by AI

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The error E0603: function run_simple is private indicates that the run_simple function in simple.rs is private (lacking the pub keyword), so it cannot be accessed from main.rs. In Rust, functions are private by default and need to be explicitly made public with pub to be accessible outside their module.

Steps to Fix the Error

1. Make run_simple Public:
   • Open src/simple.rs.
   • Add the pub keyword to the run_simple function to make it publicly accessible.
   • Example:

     pub fn run_simple() {
         // Existing function body
         println!("Hello from run_simple!");
     }
     

2. Ensure Proper Module Declaration:
   • In src/main.rs, ensure you have declared the simple module correctly:

     mod simple; // Declares the simple module
     
     fn main() {
         simple::run_simple(); // Calls the public function
     }
     

3. Rebuild and Run:
   • After making the function public, rebuild the project:

     cargo build
     

   • If the build succeeds, run the program:

     cargo run
     

4. Check for Other Issues:
   • The error mentions src/simple.rs:47:1, so verify that the run_simple function at that line is correctly defined and doesn’t have other issues (e.g., syntax errors or missing dependencies).
   • If simple.rs uses external crates, ensure they are listed in Cargo.toml under [dependencies].
5. Cargo Warning:
   • The warning about edition2024 suggests you’re using a feature flag in Cargo.toml that’s no longer needed since Rust 1.85 stabilized the 2024 edition. To clean this up, open Cargo.toml and remove the edition2024 feature if present (e.g., under [features] or cargo-features). Instead, set the edition directly:

     [package]
     name = "example"
     version = "0.1.0"
     edition = "2024"
     

   • This ensures your project uses the 2024 edition without the deprecated feature flag.

Example Files

To clarify, here’s how your files should look:

src/simple.rs:

pub fn run_simple() {
    println!("Hello from run_simple!");
}

src/main.rs:

mod simple;

fn main() {
    simple::run_simple();
}

Cargo.toml (minimal example):

[package]
name = "example"
version = "0.1.0"
edition = "2024"

Additional Notes

• If run_simple depends on other code or modules, ensure those are also public if accessed from main.rs.
• If the error persists, share the contents of src/simple.rs (especially around line 47) and src/main.rs for more specific guidance.
• The rustc --explain E0603 command provides detailed documentation on this error, which you can run for further insight.
• The target/debug directory will contain the compiled binary (example) after a successful build.

Try these steps and let me know if you encounter further issues!

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