diff --git a/src/doc/unstable-book/src/compiler-flags/codegen-backend.md b/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
index 28f173cb0f37..efccff42caae 100644
--- a/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
+++ b/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
@@ -12,7 +12,7 @@ backend. The library must contain a function named `__rustc_codegen_backend`
 with a signature of `fn() -> Box<dyn rustc_codegen_ssa::traits::CodegenBackend>`.
 
 ## Example
-```rust
+```rust,ignore
 use rustc_codegen_ssa::traits::CodegenBackend;
 
 struct MyBackend;