Merge pull request #2841 from dtolnay/serializewith

Reduce scope of quote_spanned on SerializeWith wrapper

serde_derive/src/dummy.rs

@@ -14,12 +14,7 @@ pub fn wrap_in_const(serde_path: Option<&syn::Path>, code: TokenStream) -> Token
 
  quote! {
  #[doc(hidden)]
- #[allow(
- clippy::needless_lifetimes,
- non_upper_case_globals,
- unused_attributes,
- unused_qualifications,
- )]
+ #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
  const _: () = {
  #use_serde
  #code

serde_derive/src/ser.rs

@@ -1224,11 +1224,13 @@ fn wrap_serialize_with(
  // We attach span of the path to this piece so error will be reported
  // on the #[serde(with = "...")]
  // ^^^^^
- quote_spanned!(serialize_with.span()=> {
+ let wrapper_serialize = quote_spanned! {serialize_with.span()=>
+ #serialize_with(#(self.values.#field_access, )* __s)
+ };
+
+ quote!({
  #[doc(hidden)]
  struct __SerializeWith #wrapper_impl_generics #where_clause {
- // If #field_tys is empty, this field is unused
- #[allow(dead_code)]
  values: (#(&'__a #field_tys, )*),
  phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
  }
@@ -1238,7 +1240,7 @@ fn wrap_serialize_with(
  where
  __S: _serde::Serializer,
  {
- #serialize_with(#(self.values.#field_access, )* __s)
+ #wrapper_serialize
  }
  }