error[E0277]: the trait bound `NonDefault: Default` is not satisfied
 --> tests/builder/default-missing.rs:5:10
  |
5 | #[derive(Builder)]
  |          ^^^^^^^ the trait `Default` is not implemented for `NonDefault`
  |
note: required by a bound in `Option::<T>::unwrap_or_default`
 --> $RUST/core/src/option.rs
  = note: this error originates in the derive macro `Builder` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider annotating `NonDefault` with `#[derive(Default)]`
  |
3 + #[derive(Default)]
4 | pub struct NonDefault {}
  |