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//! This test ensures custom errors don't need a conversion from `UninitializedFieldError`
//! if uninitialized fields are impossible.
#[macro_use]
extern crate derive_builder;
#[derive(Default, Builder)]
#[builder(default, build_fn(validate = "check_person", error = "Error"))]
struct Person {
name: String,
age: u16,
}
/// An error that deliberately doesn't have `impl From<UninitializedFieldError>`; as long
/// as `PersonBuilder` uses `Person::default` then missing field errors are never possible.
enum Error {
UnpopularName(String),
UnrealisticAge(u16),
}
fn check_age_realistic(age: u16) -> Result<(), Error> {
if age > 150 {
Err(Error::UnrealisticAge(age))
} else {
Ok(())
}
}
fn check_name_popular(name: &str) -> Result<(), Error> {
if name.starts_with('B') {
Err(Error::UnpopularName(name.to_string()))
} else {
Ok(())
}
}
fn check_person(builder: &PersonBuilder) -> Result<(), Error> {
if let Some(age) = &builder.age {
check_age_realistic(*age)?;
}
if let Some(name) = &builder.name {
check_name_popular(name)?;
}
Ok(())
}
fn main() {}
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