Error code E0368
A binary assignment operator like +=
or ^=
was applied to a type that
doesn't support it.
Erroneous code example:
#![allow(unused)] fn main() { let mut x = 12f32; // error: binary operation `<<` cannot be applied to // type `f32` x <<= 2; }
To fix this error, please check that this type implements this binary operation. Example:
#![allow(unused)] fn main() { let mut x = 12u32; // the `u32` type does implement the `ShlAssign` trait x <<= 2; // ok! }
It is also possible to overload most operators for your own type by
implementing the [OP]Assign
traits from std::ops
.
Another problem you might be facing is this: suppose you've overloaded the +
operator for some type Foo
by implementing the std::ops::Add
trait for
Foo
, but you find that using +=
does not work, as in this example:
use std::ops::Add; struct Foo(u32); impl Add for Foo { type Output = Foo; fn add(self, rhs: Foo) -> Foo { Foo(self.0 + rhs.0) } } fn main() { let mut x: Foo = Foo(5); x += Foo(7); // error, `+=` cannot be applied to the type `Foo` }
This is because AddAssign
is not automatically implemented, so you need to
manually implement it for your type.