#![feature(unboxed_closures)]
fn to_fn<A, F:Fn<A>>(f: F) -> F { f }
fn main() {
let mut x = 0;
let _f = to_fn(|| x = 42); //~ ERROR cannot assign to `x`
}help: consider changing this to accept closures that implement `FnMut`
--> $DIR/borrow-immutable-upvar-mutation.rs:15:24
|
LL | let _f = to_fn(|| x = 42);
| ^^^^^^^^^
This is confusing, as it appears to suggest the user change the closure to "accept closures". The span is incorrect: we should use the span of the function to_fn, not the span of the closure.
This is confusing, as it appears to suggest the user change the closure to "accept closures". The span is incorrect: we should use the span of the function
to_fn, not the span of the closure.