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rustcompiler-warnings

How do you disable dead code warnings at the crate level in Rust?

While tinkering in Rust, I repeatedly encountered a lot of dead code warnings that made it difficult to focus. I tried using the outer attribute #[allow(dead_code)], but it only silences one warning at a time.

struct SemanticDirection;

fn main() {}

warning: struct `SemanticDirection` is never constructed
 --> src\main.rs:1:8
  |
1 | struct SemanticDirection;
  |        ^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(dead_code)]` on by default

How do I disable these warnings at the crate level?

Solution

  • You can either:

    • Add an allow attribute on a struct, module, function, etc.:

      #[allow(dead_code)]
struct SemanticDirection;

    • Add an allow as a crate-level attribute; notice the !:

      #![allow(dead_code)]

    • Pass it to rustc:

      rustc -A dead_code main.rs

    • Pass it using cargo via the RUSTFLAGS environment variable:

      RUSTFLAGS="$RUSTFLAGS -A dead_code" cargo build