error[E0133]: use of mutable static is unsafe and requires unsafe function or block --> $DIR/static-mut-requires-unsafe.rs:7:5 | LL | a += 3; | ^ use of mutable static | = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior error[E0133]: use of mutable static is unsafe and requires unsafe function or block --> $DIR/static-mut-requires-unsafe.rs:8:5 | LL | a = 4; | ^ use of mutable static | = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior error[E0133]: use of mutable static is unsafe and requires unsafe function or block --> $DIR/static-mut-requires-unsafe.rs:9:14 | LL | let _b = a; | ^ use of mutable static | = note: mutable statics can be mutated by multiple threads: aliasing violations or data races will cause undefined behavior error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0133`.