pub fn downcast_mut<T: Fail>(&mut self) -> Option<&mut T> {
        if self.__private_get_type_id__() == TypeId::of::<T>() {
            unsafe { Some(&mut *(self as *mut dyn Fail as *mut T)) }
        } else {
            None
        }
    }
/// Attempts to downcast this failure to a concrete type by mutable
/// reference.
///
/// If the underlying error is not of type `T`, this will return `None`.
Attempts to downcast this failure to a concrete type by mutable
reference.

If the underlying error is not of type `T`, this will return `None`.
Attempts to downcast this failure to a concrete type by mutable reference . If the underlying error is not of type ` T ` this will return ` None ` .
pub fn downcast_mut<T: Fail>(&mut self) -> Option<&mut T> {
        if self.__private_get_type_id__() == TypeId::of::<T>() {
            unsafe { Some(&mut *(self as *mut dyn Fail as *mut T)) }
        } else {
            None
        }
    }
pub fn downcast_mut < T : Fail > ( & mut self ) -> Option < & mut T > { if self . __private_get_type_id__ ( ) == TypeId :: of :: < T > ( ) { unsafe { Some ( & mut * ( self as * mut dyn Fail as * mut T ) ) } } else { None } }
Attempts to downcast this failure to a concrete type by mutable
reference.
Attempts to downcast this failure to a concrete type by mutable reference .
&mut self
&mut self