diff --git a/serde_derive/src/de.rs b/serde_derive/src/de.rs index 5d0c00f3..2dc814a0 100644 --- a/serde_derive/src/de.rs +++ b/serde_derive/src/de.rs @@ -1728,6 +1728,15 @@ fn deserialize_externally_tagged_variant( } } +/// Generates significant part of the `Visitor::visit_seq` and `Visitor::visit_map` +/// bodies of visitors for deserializing variants of internally tagged enum: +/// +/// ```ignore +/// #[serde(tag = "...")] +/// enum InternallyTagged { +/// ... +/// } +/// ``` fn deserialize_internally_tagged_variant( params: &Parameters, variant: &Variant, @@ -1779,11 +1788,9 @@ fn deserialize_untagged_variant( deserializer: TokenStream, ) -> Fragment { if let Some(path) = variant.attrs.deserialize_with() { - let (wrapper, wrapper_ty, unwrap_fn) = wrap_deserialize_variant_with(params, variant, path); + let unwrap_fn = unwrap_to_variant_closure(params, variant, quote!(__wrap)); return quote_block! { - #wrapper - _serde::__private::Result::map( - <#wrapper_ty as _serde::Deserialize>::deserialize(#deserializer), #unwrap_fn) + _serde::__private::Result::map(#path(#deserializer), #unwrap_fn) }; } @@ -2883,44 +2890,54 @@ fn wrap_deserialize_variant_with( variant: &Variant, deserialize_with: &syn::ExprPath, ) -> (TokenStream, TokenStream, TokenStream) { - let this = ¶ms.this; - let variant_ident = &variant.ident; - let field_tys = variant.fields.iter().map(|field| field.ty); let (wrapper, wrapper_ty) = wrap_deserialize_with(params, "e!((#(#field_tys),*)), deserialize_with); + let unwrap_fn = unwrap_to_variant_closure(params, variant, quote!(__wrap.value)); + + (wrapper, wrapper_ty, unwrap_fn) +} + +/// Generates closure that converts single input parameter to the final value +fn unwrap_to_variant_closure( + params: &Parameters, + variant: &Variant, + wrapper: TokenStream, +) -> TokenStream { + let this = ¶ms.this; + let variant_ident = &variant.ident; + let field_access = (0..variant.fields.len()).map(|n| { Member::Unnamed(Index { index: n as u32, span: Span::call_site(), }) }); - let unwrap_fn = match variant.style { + + match variant.style { Style::Struct if variant.fields.len() == 1 => { let member = &variant.fields[0].member; quote! { - |__wrap| #this::#variant_ident { #member: __wrap.value } + |__wrap| #this::#variant_ident { #member: #wrapper } } } Style::Struct => { let members = variant.fields.iter().map(|field| &field.member); quote! { - |__wrap| #this::#variant_ident { #(#members: __wrap.value.#field_access),* } + |__wrap| #this::#variant_ident { #(#members: #wrapper.#field_access),* } } } Style::Tuple => quote! { - |__wrap| #this::#variant_ident(#(__wrap.value.#field_access),*) + |__wrap| #this::#variant_ident(#(#wrapper.#field_access),*) }, Style::Newtype => quote! { - |__wrap| #this::#variant_ident(__wrap.value) + |__wrap| #this::#variant_ident(#wrapper) }, Style::Unit => quote! { |__wrap| #this::#variant_ident }, - }; - - (wrapper, wrapper_ty, unwrap_fn) + } } fn expr_is_missing(field: &Field, cattrs: &attr::Container) -> Fragment {