1 error[E0596]: cannot borrow data in a `&` reference as mutable
2 --> $DIR/issue-19163.rs:9:5
4 LL | mywrite!(&v, "Hello world");
5 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot borrow as mutable
7 = note: this error originates in the macro `mywrite` (in Nightly builds, run with -Z macro-backtrace for more info)
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0596`.