error[E0658]: use of unstable library feature 'core_intrinsics': intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library --> $DIR/unchecked_math_unstable.rs:4:19 | LL | let add = std::intrinsics::unchecked_add(x, y); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(core_intrinsics)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error[E0658]: use of unstable library feature 'core_intrinsics': intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library --> $DIR/unchecked_math_unstable.rs:5:19 | LL | let sub = std::intrinsics::unchecked_sub(x, y); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(core_intrinsics)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error[E0658]: use of unstable library feature 'core_intrinsics': intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library --> $DIR/unchecked_math_unstable.rs:6:19 | LL | let mul = std::intrinsics::unchecked_mul(x, y); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: add `#![feature(core_intrinsics)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0658`.