error[E0130]: patterns aren't allowed in foreign function declarations --> $DIR/no-patterns-in-args.rs:12:11 | LL | fn f1(mut arg: u8); //~ ERROR patterns aren't allowed in foreign function declarations | ^^^^^^^ pattern not allowed in foreign function error[E0130]: patterns aren't allowed in foreign function declarations --> $DIR/no-patterns-in-args.rs:13:11 | LL | fn f2(&arg: u8); //~ ERROR patterns aren't allowed in foreign function declarations | ^^^^ pattern not allowed in foreign function error[E0130]: patterns aren't allowed in foreign function declarations --> $DIR/no-patterns-in-args.rs:14:11 | LL | fn f3(arg @ _: u8); //~ ERROR patterns aren't allowed in foreign function declarations | ^^^^^^^ pattern not allowed in foreign function error[E0561]: patterns aren't allowed in function pointer types --> $DIR/no-patterns-in-args.rs:20:14 | LL | type A1 = fn(mut arg: u8); //~ ERROR patterns aren't allowed in function pointer types | ^^^^^^^ error[E0561]: patterns aren't allowed in function pointer types --> $DIR/no-patterns-in-args.rs:21:14 | LL | type A2 = fn(&arg: u8); //~ ERROR patterns aren't allowed in function pointer types | ^^^^ error: aborting due to 5 previous errors You've got a few errors: E0130, E0561 If you want more information on an error, try using "rustc --explain E0130"