struct Foo;
struct FooBuilder<'a> {
    foo: &'a Foo,
}

impl Foo {
    fn build(&self) -> FooBuilder {
        FooBuilder { foo: &self }
    }
}

impl<'a> FooBuilder<'a> {
    // correct: other lifetime for self
    fn enable<'b>(&'b mut self) -> &'b mut FooBuilder<'a> {
        self
    }

    // wrong: can only call once
    fn disable(&'a mut self) -> &'a mut FooBuilder {
        self
    }
}

fn main() {
    let foo = Foo {};
    let mut builder = foo.build();
    builder.enable();
    builder.disable();
}