Use the compile_error! macro to halt compilation with a custom message when specific conditions are not met.
Use the compile_error! macro to force a compilation failure with a custom message when a condition is not met. This macro takes a single string argument and halts the build immediately, preventing the code from compiling if the logic inside is invalid.
compile_error!("This feature requires Rust 1.94.0 or higher");
You can also use it conditionally with cfg attributes to enforce platform-specific constraints or feature flags.
The compile_error! macro acts like a hard stop sign for your code before it even runs. If you use it, the compiler will refuse to build your project and show you the exact message you wrote. It is useful for catching configuration mistakes or unsupported features early, similar to a guard rail that prevents you from driving off a cliff.