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use proc_macro2::TokenStream;
use quote::{quote, ToTokens, TokenStreamExt};
/// Declares the local variable into which errors will be accumulated.
#[derive(Default)]
pub struct ErrorDeclaration {
__hidden: (),
}
impl ToTokens for ErrorDeclaration {
fn to_tokens(&self, tokens: &mut TokenStream) {
tokens.append_all(quote! {
let mut __errors = ::darling::Error::accumulator();
})
}
}
/// Returns early if attribute or body parsing has caused any errors.
#[derive(Default)]
pub struct ErrorCheck<'a> {
location: Option<&'a str>,
__hidden: (),
}
impl<'a> ErrorCheck<'a> {
pub fn with_location(location: &'a str) -> Self {
ErrorCheck {
location: Some(location),
__hidden: (),
}
}
}
impl<'a> ToTokens for ErrorCheck<'a> {
fn to_tokens(&self, tokens: &mut TokenStream) {
let at_call = if let Some(ref s) = self.location {
quote!(.map_err(|e| e.at(#s)))
} else {
quote!()
};
tokens.append_all(quote! {
__errors.finish() #at_call?;
})
}
}