1// SPDX-License-Identifier: Apache-2.0 OR MIT
2
3use crate::derive::prelude::*;
4
5pub(crate) const NAME: &[&str] = &["Error"];
6
7pub(crate) fn derive(_cx: &Context, data: &Data) -> Result<TokenStream> {
8 let ident: &Ident = &data.ident;
9 let source: impl Iterator =
10 data.variant_idents().map(|v: &Ident| quote!(#ident::#v(x) => ::std::option::Option::Some(x)));
11
12 let source: ImplItem = parse_quote! {
13 fn source(&self) -> ::std::option::Option<&(dyn (::std::error::Error) + 'static)> {
14 match self { #(#source,)* }
15 }
16 };
17
18 let mut impl_: EnumImpl<'_> =
19 EnumImpl::from_trait(data, &parse_quote!(::std::error::Error), supertraits_types:None, trait_def:parse_quote! {
20 trait Error {
21 #[allow(deprecated)]
22 fn description(&self) -> &str;
23 }
24 });
25
26 data.field_types().for_each(|f: &Type| impl_.push_where_predicate(parse_quote!(#f: 'static)));
27 impl_.push_item(source);
28
29 Ok(impl_.build())
30}
31