pub trait MapMut: UserData {
    type Err: Debug;

    fn map_mut<F, U>(&self, op: F) -> Result<U, Self::Err>
    where
        F: FnOnce(&mut Self::Target) -> U
; }
Expand description

Trait for wrappers that can be mapped mutably.

Required Associated Types

Required Methods

Maps a &mut T to U. Called for methods that take &mut self.

Implementations of this method must not panic. Failures should be indicated by returning Err.

Implementors