Understanding Rust Error E0519

Rust Error E0519 Explained

Rust Error E0519 occurs when the current crate is indistinguishable from one of its dependencies in terms of metadata. In other words, the compiler cannot differentiate between symbols from the current crate and a dependent crate with the same metadata. This issue might lead to symbol conflicts and erroneous code execution.

Error E0519 Code Example

#![crate_name = "a"]
#![crate_type = "lib"]

pub fn foo() {}

#![crate_name = "a"]
#![crate_type = "lib"]

// error: the current crate is indistinguishable from one of its dependencies:
//        it has the same crate-name `a` and was compiled with the same
//        `-C metadata` arguments. This will result in symbol conflicts between
//        the two.
extern crate a;

pub fn foo() {}

fn bar() {
    a::foo(); // is this calling the local crate or the dependency?

In the example above, two crates named 'a' are compiled with the same crate_type and any other metadata. This situation causes Error E0519 because the compiler is unable to distinguish between the symbols (public item names) from each crate.

Resolving Rust Error E0519

There are two ways to fix Rust Error E0519:

1. Use Cargo, the Rust package manager

Cargo is the Rust package manager that handles dependencies and compilation by default. Using Cargo can automatically resolve this issue without manual intervention. To fix Error E0519 using Cargo, just follow your typical Cargo workflow, and it will handle crate naming and dependencies for you.

2. Recompile the crates with distinct metadata

If you're not using Cargo, you can manually recompile the crates with different metadata. This solution requires changing the crate_name attribute and/or the crate_type attribute for either crate to ensure unique metadata for each crate.

After applying one of these solutions, the compiler should be able to distinguish between the symbols from each crate, thus resolving Rust Error E0519.