The build function in Builder derive macro should take ownership

[dupeiran001]

In the build derive macro, 04-call-builder, the build function takes a &mut self, and it returns a Command with the ownership of the fields. So I have to clone the fields in the implementation, which is not correct I suppose.

The build function should take the ownership of Builder, and return a builded result.

like this:

fn build(self) -> Result<Command, dyn Error>{
    unimplemented!()
}

[shouya]

So I have to clone the fields in the implementation

To avoid cloning, you can look into Option::take as well as Vec::split_off.