Closed
Description
openedon May 29, 2018
fn test(f: Box<FnMut()>) {
let _f = move || {
f()
};
}
error[E0596]: cannot borrow immutable `Box` content `**f` as mutable
--> src/main.rs:3:9
|
3 | f()
| ^ cannot borrow as mutableThis error message seems a bit weird, because the problem isn't that box content isn't mutable, but the box itself is immutable. Changing the line 2 to let mut f: … fixes the issue. Notice that the same error message is shown if we construct f within the function.
I think the error message should be improved to look similar to the following (not sure on the phrasing of the error itself):
error[E0596]: cannot borrow immutable argument `Box` as mutable
--> src/main.rs:2:5
|
1 | fn test(f: Box<FnMut()>) {
| - consider changing this to `mut f`
2 | let _f = move || {
3 | f()
| ^ cannot borrow mutablySign up for free to join this conversation on GitHub. Already have an account? Sign in to comment