mirrors/thiserror
1
0
Fork 0
mirror of https://github.com/dtolnay/thiserror.git synced 2025-04-06 06:17:39 +03:00
Code Issues Projects Releases Packages Wiki Activity

Improve span of missing Display impl error

Browse source
This commit is contained in:
David Tolnay 2020-04-11 10:26:12 -07:00
parent b649704973
commit 4885372ced
No known key found for this signature in database
GPG key ID: F9BA143B95FF6D82
3 changed files with 33 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

29
impl/src/expand.rs
View file

@ -2,7 +2,7 @@ use crate::ast::{Enum, Field, Input, Struct};
use proc_macro2::TokenStream;
use quote::{format_ident, quote, quote_spanned, ToTokens};
use syn::spanned::Spanned;
use syn::{DeriveInput, Member, PathArguments, Result, Type};
use syn::{Data, DeriveInput, Member, PathArguments, Result, Type, Visibility};
pub fn derive(node: &DeriveInput) -> Result<TokenStream> {
let input = Input::from_syn(node)?;
@ -135,8 +135,10 @@ fn impl_struct(input: Struct) -> TokenStream {
}
});
let error_trait = spanned_error_trait(input.original);
quote! {
impl #impl_generics std::error::Error for #ty #ty_generics #where_clause {
impl #impl_generics #error_trait for #ty #ty_generics #where_clause {
#source_method
#backtrace_method
}
@ -321,8 +323,10 @@ fn impl_enum(input: Enum) -> TokenStream {
})
});
let error_trait = spanned_error_trait(input.original);
quote! {
impl #impl_generics std::error::Error for #ty #ty_generics #where_clause {
impl #impl_generics #error_trait for #ty #ty_generics #where_clause {
#source_method
#backtrace_method
}
@ -382,3 +386,22 @@ fn type_is_option(ty: &Type) -> bool {
_ => false,
}
}
fn spanned_error_trait(input: &DeriveInput) -> TokenStream {
let vis_span = match &input.vis {
Visibility::Public(vis) => Some(vis.pub_token.span()),
Visibility::Crate(vis) => Some(vis.crate_token.span()),
Visibility::Restricted(vis) => Some(vis.pub_token.span()),
Visibility::Inherited => None,
};
let data_span = match &input.data {
Data::Struct(data) => data.struct_token.span(),
Data::Enum(data) => data.enum_token.span(),
Data::Union(data) => data.union_token.span(),
};
let first_span = vis_span.unwrap_or(data_span);
let last_span = input.ident.span();
let path = quote_spanned!(first_span=> std::error::);
let error = quote_spanned!(last_span=> Error);
quote!(#path #error)
}