Error code E0133
Unsafe code was used outside of an unsafe block.
Erroneous code example:
unsafe fn f() { return; } // This is the unsafe code fn main() { f(); // error: call to unsafe function requires unsafe function or block }
Using unsafe functionality is potentially dangerous and disallowed by safety checks. Examples:
- Dereferencing raw pointers
- Calling functions via FFI
- Calling functions marked unsafe
These safety checks can be relaxed for a section of the code by wrapping the
unsafe instructions with an unsafe
block. For instance:
unsafe fn f() { return; } fn main() { unsafe { f(); } // ok! }
See the unsafe section of the Book for more details.
Unsafe code in functions
Unsafe code is currently accepted in unsafe functions, but that is being phased out in favor of requiring unsafe blocks here too.
#![allow(unused)] fn main() { unsafe fn f() { return; } unsafe fn g() { f(); // Is accepted, but no longer recommended unsafe { f(); } // Recommended way to write this } }
Linting against this is controlled via the unsafe_op_in_unsafe_fn
lint, which
is allow
by default but will be upgraded to warn
in a future edition.