Error code E0595
Note: this error code is no longer emitted by the compiler.
Closures cannot mutate immutable captured variables.
Erroneous code example:
#![allow(unused)] fn main() { let x = 3; // error: closure cannot assign to immutable local variable `x` let mut c = || { x += 1 }; }
Make the variable binding mutable:
#![allow(unused)] fn main() { let mut x = 3; // ok! let mut c = || { x += 1 }; }