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darling 0.3.0

A proc-macro library for reading attributes into structs when implementing custom derives.
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//! In case of bad input, parsing should fail. The error should have locations set in derived implementations.
#[macro_use]
extern crate darling;
extern crate syn;

use darling::FromDeriveInput;

#[derive(Debug, FromMetaItem)]
struct Dolor {
    #[darling(rename = "amet")]
    sit: bool,
    world: bool,
}

#[derive(Debug, FromDeriveInput)]
#[darling(from_ident, attributes(hello))]
struct Lorem {
    ident: syn::Ident,
    ipsum: Dolor,
}

impl From<syn::Ident> for Lorem {
    fn from(ident: syn::Ident) -> Self {
        Lorem {
            ident,
            ipsum: Dolor {
                sit: false,
                world: true,
            },
        }
    }
}

#[test]
fn parsing_fail() {
    let di = syn::parse_str(r#"
        #[hello(ipsum(amet = "yes", world = false))]
        pub struct Foo;
    "#).unwrap();

    println!("{}", Lorem::from_derive_input(&di).unwrap_err());
}

#[test]
fn missing_field() {
    let di = syn::parse_str(r#"
        #[hello(ipsum(amet = true))]
        pub struct Foo;
    "#).unwrap();

    println!("{}", Lorem::from_derive_input(&di).unwrap_err());
}