Make all use of __private go through interpolation

serde_derive/src/internals/ast.rs

@@ -1,6 +1,7 @@
 //! A Serde ast, parsed from the Syn ast and ready to generate Rust code.
 
 use crate::internals::{attr, check, Ctxt, Derive};
+use proc_macro2::Ident;
 use syn::punctuated::Punctuated;
 use syn::Token;
 
@@ -62,13 +63,17 @@ impl<'a> Container<'a> {
         cx: &Ctxt,
         item: &'a syn::DeriveInput,
         derive: Derive,
+        private: &Ident,
     ) -> Option<Container<'a>> {
         let attrs = attr::Container::from_ast(cx, item);
 
         let mut data = match &item.data {
-            syn::Data::Enum(data) => Data::Enum(enum_from_ast(cx, &data.variants, attrs.default())),
+            syn::Data::Enum(data) => {
+                Data::Enum(enum_from_ast(cx, &data.variants, attrs.default(), private))
+            }
             syn::Data::Struct(data) => {
-                let (style, fields) = struct_from_ast(cx, &data.fields, None, attrs.default());
+                let (style, fields) =
+                    struct_from_ast(cx, &data.fields, None, attrs.default(), private);
                 Data::Struct(style, fields)
             }
             syn::Data::Union(_) => {
@@ -129,13 +134,19 @@ fn enum_from_ast<'a>(
     cx: &Ctxt,
     variants: &'a Punctuated<syn::Variant, Token![,]>,
     container_default: &attr::Default,
+    private: &Ident,
 ) -> Vec<Variant<'a>> {
     let variants: Vec<Variant> = variants
         .iter()
         .map(|variant| {
             let attrs = attr::Variant::from_ast(cx, variant);
-            let (style, fields) =
-                struct_from_ast(cx, &variant.fields, Some(&attrs), container_default);
+            let (style, fields) = struct_from_ast(
+                cx,
+                &variant.fields,
+                Some(&attrs),
+                container_default,
+                private,
+            );
             Variant {
                 ident: variant.ident.clone(),
                 attrs,
@@ -165,19 +176,20 @@ fn struct_from_ast<'a>(
     fields: &'a syn::Fields,
     attrs: Option<&attr::Variant>,
     container_default: &attr::Default,
+    private: &Ident,
 ) -> (Style, Vec<Field<'a>>) {
     match fields {
         syn::Fields::Named(fields) => (
             Style::Struct,
-            fields_from_ast(cx, &fields.named, attrs, container_default),
+            fields_from_ast(cx, &fields.named, attrs, container_default, private),
         ),
         syn::Fields::Unnamed(fields) if fields.unnamed.len() == 1 => (
             Style::Newtype,
-            fields_from_ast(cx, &fields.unnamed, attrs, container_default),
+            fields_from_ast(cx, &fields.unnamed, attrs, container_default, private),
         ),
         syn::Fields::Unnamed(fields) => (
             Style::Tuple,
-            fields_from_ast(cx, &fields.unnamed, attrs, container_default),
+            fields_from_ast(cx, &fields.unnamed, attrs, container_default, private),
         ),
         syn::Fields::Unit => (Style::Unit, Vec::new()),
     }
@@ -188,6 +200,7 @@ fn fields_from_ast<'a>(
     fields: &'a Punctuated<syn::Field, Token![,]>,
     attrs: Option<&attr::Variant>,
     container_default: &attr::Default,
+    private: &Ident,
 ) -> Vec<Field<'a>> {
     fields
         .iter()
@@ -197,7 +210,7 @@ fn fields_from_ast<'a>(
                 Some(ident) => syn::Member::Named(ident.clone()),
                 None => syn::Member::Unnamed(i.into()),
             },
-            attrs: attr::Field::from_ast(cx, i, field, attrs, container_default),
+            attrs: attr::Field::from_ast(cx, i, field, attrs, container_default, private),
             ty: &field.ty,
             original: field,
         })

serde_derive/src/internals/attr.rs

@@ -1024,6 +1024,7 @@ impl Field {
         field: &syn::Field,
         attrs: Option<&Variant>,
         container_default: &Default,
+        private: &Ident,
     ) -> Self {
         let mut ser_name = Attr::none(cx, RENAME);
         let mut de_name = Attr::none(cx, RENAME);
@@ -1217,7 +1218,7 @@ impl Field {
                 };
                 let span = Span::call_site();
                 path.segments.push(Ident::new("_serde", span).into());
-                path.segments.push(Ident::new("__private", span).into());
+                path.segments.push(private.clone().into());
                 path.segments.push(Ident::new("de", span).into());
                 path.segments
                     .push(Ident::new("borrow_cow_str", span).into());
@@ -1234,7 +1235,7 @@ impl Field {
                 };
                 let span = Span::call_site();
                 path.segments.push(Ident::new("_serde", span).into());
-                path.segments.push(Ident::new("__private", span).into());
+                path.segments.push(private.clone().into());
                 path.segments.push(Ident::new("de", span).into());
                 path.segments
                     .push(Ident::new("borrow_cow_bytes", span).into());

serde_derive/src/lib.rs

@@ -75,6 +75,8 @@ extern crate proc_macro;
 mod internals;
 
 use proc_macro::TokenStream;
+use proc_macro2::{Ident, Span};
+use quote::{ToTokens, TokenStreamExt as _};
 use syn::parse_macro_input;
 use syn::DeriveInput;
 
@@ -89,6 +91,21 @@ mod pretend;
 mod ser;
 mod this;
 
+#[allow(non_camel_case_types)]
+struct private;
+
+impl private {
+    fn ident(&self) -> Ident {
+        Ident::new("__private", Span::call_site())
+    }
+}
+
+impl ToTokens for private {
+    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
+        tokens.append(self.ident());
+    }
+}
+
 #[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {
     let mut input = parse_macro_input!(input as DeriveInput);

serde_derive/src/pretend.rs

@@ -1,4 +1,5 @@
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
+use crate::private;
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
 
@@ -83,8 +84,8 @@ fn pretend_fields_used_struct(cont: &Container, fields: &[Field]) -> TokenStream
     let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
 
     quote! {
-        match _serde::__private::None::<&#type_ident #ty_generics> {
-            _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {}
+        match _serde::#private::None::<&#type_ident #ty_generics> {
+            _serde::#private::Some(#type_ident { #(#members: #placeholders),* }) => {}
             _ => {}
         }
     }
@@ -96,11 +97,12 @@ fn pretend_fields_used_struct_packed(cont: &Container, fields: &[Field]) -> Toke
 
     let members = fields.iter().map(|field| &field.member).collect::<Vec<_>>();
 
+    let private2 = private;
     quote! {
-        match _serde::__private::None::<&#type_ident #ty_generics> {
-            _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => {
+        match _serde::#private::None::<&#type_ident #ty_generics> {
+            _serde::#private::Some(__v @ #type_ident { #(#members: _),* }) => {
                 #(
-                    let _ = _serde::__private::ptr::addr_of!(__v.#members);
+                    let _ = _serde::#private2::ptr::addr_of!(__v.#members);
                 )*
             }
             _ => {}
@@ -125,10 +127,11 @@ fn pretend_fields_used_enum(cont: &Container, variants: &[Variant]) -> TokenStre
         })
         .collect::<Vec<_>>();
 
+    let private2 = private;
     quote! {
-        match _serde::__private::None::<&#type_ident #ty_generics> {
+        match _serde::#private::None::<&#type_ident #ty_generics> {
             #(
-                _serde::__private::Some(#patterns) => {}
+                _serde::#private2::Some(#patterns) => {}
             )*
             _ => {}
         }
@@ -172,8 +175,8 @@ fn pretend_variants_used(cont: &Container) -> TokenStream {
         };
 
         quote! {
-            match _serde::__private::None {
-                _serde::__private::Some((#(#placeholders,)*)) => {
+            match _serde::#private::None {
+                _serde::#private::Some((#(#placeholders,)*)) => {
                     let _ = #type_ident::#variant_ident #turbofish #pat;
                 }
                 _ => {}

serde_derive/src/ser.rs

@@ -2,7 +2,7 @@ use crate::fragment::{Fragment, Match, Stmts};
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
 use crate::internals::name::Name;
 use crate::internals::{attr, replace_receiver, Ctxt, Derive};
-use crate::{bound, dummy, pretend, this};
+use crate::{bound, dummy, pretend, private, this};
 use proc_macro2::{Span, TokenStream};
 use quote::{quote, quote_spanned};
 use syn::spanned::Spanned;
@@ -12,7 +12,7 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke
     replace_receiver(input);
 
     let ctxt = Ctxt::new();
-    let cont = match Container::from_ast(&ctxt, input, Derive::Serialize) {
+    let cont = match Container::from_ast(&ctxt, input, Derive::Serialize, &private.ident()) {
         Some(cont) => cont,
         None => return Err(ctxt.check().unwrap_err()),
     };
@@ -31,7 +31,7 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke
         quote! {
             #[automatically_derived]
             impl #impl_generics #ident #ty_generics #where_clause {
-                #vis fn serialize<__S>(__self: &#remote #ty_generics, __serializer: __S) -> #serde::__private::Result<__S::Ok, __S::Error>
+                #vis fn serialize<__S>(__self: &#remote #ty_generics, __serializer: __S) -> #serde::#private::Result<__S::Ok, __S::Error>
                 where
                     __S: #serde::Serializer,
                 {
@@ -44,7 +44,7 @@ pub fn expand_derive_serialize(input: &mut syn::DeriveInput) -> syn::Result<Toke
         quote! {
             #[automatically_derived]
             impl #impl_generics #serde::Serialize for #ident #ty_generics #where_clause {
-                fn serialize<__S>(&self, __serializer: __S) -> #serde::__private::Result<__S::Ok, __S::Error>
+                fn serialize<__S>(&self, __serializer: __S) -> #serde::#private::Result<__S::Ok, __S::Error>
                 where
                     __S: #serde::Serializer,
                 {
@@ -212,7 +212,7 @@ fn serialize_into(params: &Parameters, type_into: &syn::Type) -> Fragment {
     let self_var = &params.self_var;
     quote_block! {
         _serde::Serialize::serialize(
-            &_serde::__private::Into::<#type_into>::into(_serde::__private::Clone::clone(#self_var)),
+            &_serde::#private::Into::<#type_into>::into(_serde::#private::Clone::clone(#self_var)),
             __serializer)
     }
 }
@@ -382,7 +382,7 @@ fn serialize_struct_as_map(
     let let_mut = mut_if(serialized_fields.peek().is_some() || tag_field_exists);
 
     quote_block! {
-        let #let_mut __serde_state = _serde::Serializer::serialize_map(__serializer, _serde::__private::None)?;
+        let #let_mut __serde_state = _serde::Serializer::serialize_map(__serializer, _serde::#private::None)?;
         #tag_field
         #(#serialize_fields)*
         _serde::ser::SerializeMap::end(__serde_state)
@@ -404,7 +404,7 @@ fn serialize_enum(params: &Parameters, variants: &[Variant], cattrs: &attr::Cont
 
     if cattrs.remote().is_some() && cattrs.non_exhaustive() {
         arms.push(quote! {
-            ref unrecognized => _serde::__private::Err(_serde::ser::Error::custom(_serde::__private::ser::CannotSerializeVariant(unrecognized))),
+            ref unrecognized => _serde::#private::Err(_serde::ser::Error::custom(_serde::#private::ser::CannotSerializeVariant(unrecognized))),
         });
     }
 
@@ -431,7 +431,7 @@ fn serialize_variant(
             variant_ident
         );
         let skipped_err = quote! {
-            _serde::__private::Err(_serde::ser::Error::custom(#skipped_msg))
+            _serde::#private::Err(_serde::ser::Error::custom(#skipped_msg))
         };
         let fields_pat = match variant.style {
             Style::Unit => quote!(),
@@ -585,7 +585,7 @@ fn serialize_internally_tagged_variant(
     if let Some(path) = variant.attrs.serialize_with() {
         let ser = wrap_serialize_variant_with(params, path, variant);
         return quote_expr! {
-            _serde::__private::ser::serialize_tagged_newtype(
+            _serde::#private::ser::serialize_tagged_newtype(
                 __serializer,
                 #enum_ident_str,
                 #variant_ident_str,
@@ -614,7 +614,7 @@ fn serialize_internally_tagged_variant(
             }
 
             let span = field.original.span();
-            let func = quote_spanned!(span=> _serde::__private::ser::serialize_tagged_newtype);
+            let func = quote_spanned!(span=> _serde::#private::ser::serialize_tagged_newtype);
             quote_expr! {
                 #func(
                     __serializer,
@@ -648,7 +648,7 @@ fn serialize_adjacently_tagged_variant(
     let type_name = cattrs.name().serialize_name();
     let variant_name = variant.attrs.name().serialize_name();
     let serialize_variant = quote! {
-        &_serde::__private::ser::AdjacentlyTaggedEnumVariant {
+        &_serde::#private::ser::AdjacentlyTaggedEnumVariant {
             enum_name: #type_name,
             variant_index: #variant_index,
             variant_name: #variant_name,
@@ -731,12 +731,12 @@ fn serialize_adjacently_tagged_variant(
         #[doc(hidden)]
         struct __AdjacentlyTagged #wrapper_generics #where_clause {
             data: (#(&'__a #fields_ty,)*),
-            phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
+            phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
         }
 
         #[automatically_derived]
         impl #wrapper_impl_generics _serde::Serialize for __AdjacentlyTagged #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&self, __serializer: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&self, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
             where
                 __S: _serde::Serializer,
             {
@@ -754,7 +754,7 @@ fn serialize_adjacently_tagged_variant(
         _serde::ser::SerializeStruct::serialize_field(
             &mut __struct, #content, &__AdjacentlyTagged {
                 data: (#(#fields_ident,)*),
-                phantom: _serde::__private::PhantomData::<#this_type #ty_generics>,
+                phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
             })?;
         _serde::ser::SerializeStruct::end(__struct)
     }
@@ -996,19 +996,19 @@ fn serialize_struct_variant_with_flatten(
                 #[doc(hidden)]
                 struct __EnumFlatten #wrapper_generics #where_clause {
                     data: (#(&'__a #fields_ty,)*),
-                    phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
+                    phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
                 }
 
                 #[automatically_derived]
                 impl #wrapper_impl_generics _serde::Serialize for __EnumFlatten #wrapper_ty_generics #where_clause {
-                    fn serialize<__S>(&self, __serializer: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
+                    fn serialize<__S>(&self, __serializer: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
                     where
                         __S: _serde::Serializer,
                     {
                         let (#(#members,)*) = self.data;
                         let #let_mut __serde_state = _serde::Serializer::serialize_map(
                             __serializer,
-                            _serde::__private::None)?;
+                            _serde::#private::None)?;
                         #(#serialize_fields)*
                         _serde::ser::SerializeMap::end(__serde_state)
                     }
@@ -1021,7 +1021,7 @@ fn serialize_struct_variant_with_flatten(
                     #variant_name,
                     &__EnumFlatten {
                         data: (#(#members,)*),
-                        phantom: _serde::__private::PhantomData::<#this_type #ty_generics>,
+                        phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
                     })
             }
         }
@@ -1029,7 +1029,7 @@ fn serialize_struct_variant_with_flatten(
             quote_block! {
                 let #let_mut __serde_state = _serde::Serializer::serialize_map(
                     __serializer,
-                    _serde::__private::None)?;
+                    _serde::#private::None)?;
                 _serde::ser::SerializeMap::serialize_entry(
                     &mut __serde_state,
                     #tag,
@@ -1043,7 +1043,7 @@ fn serialize_struct_variant_with_flatten(
             quote_block! {
                 let #let_mut __serde_state = _serde::Serializer::serialize_map(
                     __serializer,
-                    _serde::__private::None)?;
+                    _serde::#private::None)?;
                 #(#serialize_fields)*
                 _serde::ser::SerializeMap::end(__serde_state)
             }
@@ -1132,7 +1132,7 @@ fn serialize_struct_visitor(
             let ser = if field.attrs.flatten() {
                 let func = quote_spanned!(span=> _serde::Serialize::serialize);
                 quote! {
-                    #func(&#field_expr, _serde::__private::ser::FlatMapSerializer(&mut __serde_state))?;
+                    #func(&#field_expr, _serde::#private::ser::FlatMapSerializer(&mut __serde_state))?;
                 }
             } else {
                 let func = struct_trait.serialize_field(span);
@@ -1239,12 +1239,12 @@ fn wrap_serialize_with(
         #[doc(hidden)]
         struct __SerializeWith #wrapper_impl_generics #where_clause {
             values: (#(&'__a #field_tys, )*),
-            phantom: _serde::__private::PhantomData<#this_type #ty_generics>,
+            phantom: _serde::#private::PhantomData<#this_type #ty_generics>,
         }
 
         #[automatically_derived]
         impl #wrapper_impl_generics _serde::Serialize for __SerializeWith #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&#self_var, #serializer_var: __S) -> _serde::__private::Result<__S::Ok, __S::Error>
+            fn serialize<__S>(&#self_var, #serializer_var: __S) -> _serde::#private::Result<__S::Ok, __S::Error>
             where
                 __S: _serde::Serializer,
             {
@@ -1254,7 +1254,7 @@ fn wrap_serialize_with(
 
         __SerializeWith {
             values: (#(#field_exprs, )*),
-            phantom: _serde::__private::PhantomData::<#this_type #ty_generics>,
+            phantom: _serde::#private::PhantomData::<#this_type #ty_generics>,
         }
     })
 }
@@ -1290,11 +1290,11 @@ fn get_member(params: &Parameters, field: &Field, member: &Member) -> TokenStrea
                 quote!(&#self_var.#member)
             };
             let ty = field.ty;
-            quote!(_serde::__private::ser::constrain::<#ty>(#inner))
+            quote!(_serde::#private::ser::constrain::<#ty>(#inner))
         }
         (true, Some(getter)) => {
             let ty = field.ty;
-            quote!(_serde::__private::ser::constrain::<#ty>(&#getter(#self_var)))
+            quote!(_serde::#private::ser::constrain::<#ty>(&#getter(#self_var)))
         }
         (false, Some(_)) => {
             unreachable!("getter is only allowed for remote impls");