Release 1.0.215

Revert the colliding aliases hard error (PRs #2562 & #2853)

.github/workflows/ci.yml

@@ -26,6 +26,7 @@ jobs:
         with:
           name: Cargo.lock
           path: Cargo.lock
+        continue-on-error: true
 
   windows:
     name: Test suite (windows)

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.211"
+version = "1.0.215"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std", "no-std::no-alloc"]
@@ -37,7 +37,7 @@ rustdoc-args = ["--generate-link-to-definition"]
 # is compatible with exactly one serde release because the generated code
 # involves nonpublic APIs which are not bound by semver.
 [target.'cfg(any())'.dependencies]
-serde_derive = { version = "=1.0.211", path = "../serde_derive" }
+serde_derive = { version = "=1.0.215", path = "../serde_derive" }
 
 
 ### FEATURES #################################################################

serde/src/de/value.rs

@@ -175,6 +175,17 @@ where
     }
 }
 
+impl<'de, E> IntoDeserializer<'de, E> for UnitDeserializer<E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<E> Debug for UnitDeserializer<E> {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         formatter.debug_struct("UnitDeserializer").finish()
@@ -225,6 +236,18 @@ where
     }
 }
 
+#[cfg(feature = "unstable")]
+impl<'de, E> IntoDeserializer<'de, E> for NeverDeserializer<E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 macro_rules! primitive_deserializer {
@@ -279,6 +302,17 @@ macro_rules! primitive_deserializer {
             }
         }
 
+        impl<'de, E> IntoDeserializer<'de, E> for $name<E>
+        where
+            E: de::Error,
+        {
+            type Deserializer = Self;
+
+            fn into_deserializer(self) -> Self {
+                self
+            }
+        }
+
         impl<E> Debug for $name<E> {
             fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                 formatter
@@ -369,6 +403,17 @@ where
     }
 }
 
+impl<'de, E> IntoDeserializer<'de, E> for U32Deserializer<E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, E> de::EnumAccess<'de> for U32Deserializer<E>
 where
     E: de::Error,
@@ -458,6 +503,17 @@ where
     }
 }
 
+impl<'de, 'a, E> IntoDeserializer<'de, E> for StrDeserializer<'a, E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, 'a, E> de::EnumAccess<'de> for StrDeserializer<'a, E>
 where
     E: de::Error,
@@ -537,6 +593,17 @@ where
     }
 }
 
+impl<'de, E> IntoDeserializer<'de, E> for BorrowedStrDeserializer<'de, E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, E> de::EnumAccess<'de> for BorrowedStrDeserializer<'de, E>
 where
     E: de::Error,
@@ -640,6 +707,18 @@ where
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de, E> IntoDeserializer<'de, E> for StringDeserializer<E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'de, E> de::EnumAccess<'de> for StringDeserializer<E>
 where
@@ -748,6 +827,18 @@ where
     }
 }
 
+#[cfg(any(feature = "std", feature = "alloc"))]
+impl<'de, 'a, E> IntoDeserializer<'de, E> for CowStrDeserializer<'a, E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 #[cfg(any(feature = "std", feature = "alloc"))]
 impl<'de, 'a, E> de::EnumAccess<'de> for CowStrDeserializer<'a, E>
 where
@@ -825,6 +916,17 @@ where
     }
 }
 
+impl<'de, 'a, E> IntoDeserializer<'de, E> for BytesDeserializer<'a, E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'a, E> Debug for BytesDeserializer<'a, E> {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         formatter
@@ -873,6 +975,17 @@ where
     }
 }
 
+impl<'de, E> IntoDeserializer<'de, E> for BorrowedBytesDeserializer<'de, E>
+where
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, E> Debug for BorrowedBytesDeserializer<'de, E> {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         formatter
@@ -952,6 +1065,19 @@ where
     }
 }
 
+impl<'de, I, T, E> IntoDeserializer<'de, E> for SeqDeserializer<I, E>
+where
+    I: Iterator<Item = T>,
+    T: IntoDeserializer<'de, E>,
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, I, T, E> de::SeqAccess<'de> for SeqDeserializer<I, E>
 where
     I: Iterator<Item = T>,
@@ -1083,6 +1209,17 @@ where
     }
 }
 
+impl<'de, A> IntoDeserializer<'de, A::Error> for SeqAccessDeserializer<A>
+where
+    A: de::SeqAccess<'de>,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 /// A deserializer that iterates over a map.
@@ -1197,6 +1334,21 @@ where
     }
 }
 
+impl<'de, I, E> IntoDeserializer<'de, E> for MapDeserializer<'de, I, E>
+where
+    I: Iterator,
+    I::Item: private::Pair,
+    First<I::Item>: IntoDeserializer<'de, E>,
+    Second<I::Item>: IntoDeserializer<'de, E>,
+    E: de::Error,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, I, E> de::MapAccess<'de> for MapDeserializer<'de, I, E>
 where
     I: Iterator,
@@ -1498,6 +1650,17 @@ where
     }
 }
 
+impl<'de, A> IntoDeserializer<'de, A::Error> for MapAccessDeserializer<A>
+where
+    A: de::MapAccess<'de>,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 impl<'de, A> de::EnumAccess<'de> for MapAccessDeserializer<A>
 where
     A: de::MapAccess<'de>,
@@ -1551,6 +1714,17 @@ where
     }
 }
 
+impl<'de, A> IntoDeserializer<'de, A::Error> for EnumAccessDeserializer<A>
+where
+    A: de::EnumAccess<'de>,
+{
+    type Deserializer = Self;
+
+    fn into_deserializer(self) -> Self {
+        self
+    }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 mod private {

serde/src/lib.rs

@@ -95,7 +95,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.211")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.215")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Show which crate feature enables conditionally compiled APIs in documentation.

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.211"
+version = "1.0.215"
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 categories = ["no-std", "no-std::no-alloc"]
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"

serde_derive/src/de.rs

@@ -1,5 +1,6 @@
 use crate::fragment::{Expr, Fragment, Match, Stmts};
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
+use crate::internals::name::Name;
 use crate::internals::{attr, replace_receiver, ungroup, Ctxt, Derive};
 use crate::{bound, dummy, pretend, this};
 use proc_macro2::{Literal, Span, TokenStream};
@@ -875,13 +876,14 @@ fn deserialize_newtype_struct(
 ) -> TokenStream {
     let delife = params.borrowed.de_lifetime();
     let field_ty = field.ty;
+    let deserializer_var = quote!(__e);
 
     let value = match field.attrs.deserialize_with() {
         None => {
             let span = field.original.span();
             let func = quote_spanned!(span=> <#field_ty as _serde::Deserialize>::deserialize);
             quote! {
-                #func(__e)?
+                #func(#deserializer_var)?
             }
         }
         Some(path) => {
@@ -890,7 +892,7 @@ fn deserialize_newtype_struct(
             // on the #[serde(with = "...")]
             //                       ^^^^^
             quote_spanned! {path.span()=>
-                #path(__e)?
+                #path(#deserializer_var)?
             }
         }
     };
@@ -906,7 +908,7 @@ fn deserialize_newtype_struct(
 
     quote! {
         #[inline]
-        fn visit_newtype_struct<__E>(self, __e: __E) -> _serde::__private::Result<Self::Value, __E::Error>
+        fn visit_newtype_struct<__E>(self, #deserializer_var: __E) -> _serde::__private::Result<Self::Value, __E::Error>
         where
             __E: _serde::Deserializer<#delife>,
         {
@@ -2001,7 +2003,7 @@ fn deserialize_untagged_newtype_variant(
 
 struct FieldWithAliases<'a> {
     ident: Ident,
-    aliases: &'a BTreeSet<String>,
+    aliases: &'a BTreeSet<Name>,
 }
 
 fn deserialize_generated_identifier(
@@ -2215,7 +2217,11 @@ fn deserialize_identifier(
         let ident = &field.ident;
         let aliases = field.aliases;
         // `aliases` also contains a main name
-        quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident))
+        quote! {
+            #(
+                #aliases => _serde::__private::Ok(#this_value::#ident),
+            )*
+        }
     });
     let bytes_mapping = deserialized_fields.iter().map(|field| {
         let ident = &field.ident;
@@ -2223,8 +2229,12 @@ fn deserialize_identifier(
         let aliases = field
             .aliases
             .iter()
-            .map(|alias| Literal::byte_string(alias.as_bytes()));
-        quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident))
+            .map(|alias| Literal::byte_string(alias.value.as_bytes()));
+        quote! {
+            #(
+                #aliases => _serde::__private::Ok(#this_value::#ident),
+            )*
+        }
     });
 
     let expecting = expecting.unwrap_or(if is_variant {
@@ -2422,7 +2432,7 @@ fn deserialize_identifier(
                 __E: _serde::de::Error,
             {
                 match __value {
-                    #(#str_mapping,)*
+                    #(#str_mapping)*
                     _ => {
                         #value_as_borrowed_str_content
                         #fallthrough_borrowed_arm
@@ -2435,7 +2445,7 @@ fn deserialize_identifier(
                 __E: _serde::de::Error,
             {
                 match __value {
-                    #(#bytes_mapping,)*
+                    #(#bytes_mapping)*
                     _ => {
                         #bytes_to_str
                         #value_as_borrowed_bytes_content
@@ -2460,7 +2470,7 @@ fn deserialize_identifier(
             __E: _serde::de::Error,
         {
             match __value {
-                #(#str_mapping,)*
+                #(#str_mapping)*
                 _ => {
                     #value_as_str_content
                     #fallthrough_arm
@@ -2473,7 +2483,7 @@ fn deserialize_identifier(
             __E: _serde::de::Error,
         {
             match __value {
-                #(#bytes_mapping,)*
+                #(#bytes_mapping)*
                 _ => {
                     #bytes_to_str
                     #value_as_bytes_content
@@ -2882,13 +2892,14 @@ fn wrap_deserialize_with(
     let (de_impl_generics, de_ty_generics, ty_generics, where_clause) =
         split_with_de_lifetime(params);
     let delife = params.borrowed.de_lifetime();
+    let deserializer_var = quote!(__deserializer);
 
     // If #deserialize_with returns wrong type, error will be reported here (^^^^^).
     // We attach span of the path to the function so it will be reported
     // on the #[serde(with = "...")]
     //                       ^^^^^
     let value = quote_spanned! {deserialize_with.span()=>
-        #deserialize_with(__deserializer)?
+        #deserialize_with(#deserializer_var)?
     };
     let wrapper = quote! {
         #[doc(hidden)]
@@ -2899,7 +2910,7 @@ fn wrap_deserialize_with(
         }
 
         impl #de_impl_generics _serde::Deserialize<#delife> for __DeserializeWith #de_ty_generics #where_clause {
-            fn deserialize<__D>(__deserializer: __D) -> _serde::__private::Result<Self, __D::Error>
+            fn deserialize<__D>(#deserializer_var: __D) -> _serde::__private::Result<Self, __D::Error>
             where
                 __D: _serde::Deserializer<#delife>,
             {

serde_derive/src/internals/attr.rs

@@ -1,3 +1,4 @@
+use crate::internals::name::{MultiName, Name};
 use crate::internals::symbol::*;
 use crate::internals::{ungroup, Ctxt};
 use proc_macro2::{Spacing, Span, TokenStream, TokenTree};
@@ -21,7 +22,7 @@ use syn::{parse_quote, token, Ident, Lifetime, Token};
 
 pub use crate::internals::case::RenameRule;
 
-struct Attr<'c, T> {
+pub(crate) struct Attr<'c, T> {
     cx: &'c Ctxt,
     name: Symbol,
     tokens: TokenStream,
@@ -62,7 +63,7 @@ impl<'c, T> Attr<'c, T> {
         }
     }
 
-    fn get(self) -> Option<T> {
+    pub(crate) fn get(self) -> Option<T> {
         self.value
     }
 
@@ -90,7 +91,7 @@ impl<'c> BoolAttr<'c> {
     }
 }
 
-struct VecAttr<'c, T> {
+pub(crate) struct VecAttr<'c, T> {
     cx: &'c Ctxt,
     name: Symbol,
     first_dup_tokens: TokenStream,
@@ -125,63 +126,13 @@ impl<'c, T> VecAttr<'c, T> {
         }
     }
 
-    fn get(self) -> Vec<T> {
+    pub(crate) fn get(self) -> Vec<T> {
         self.values
     }
 }
 
-pub struct Name {
-    serialize: String,
-    serialize_renamed: bool,
-    deserialize: String,
-    deserialize_renamed: bool,
-    deserialize_aliases: BTreeSet<String>,
-}
-
-fn unraw(ident: &Ident) -> String {
-    ident.to_string().trim_start_matches("r#").to_owned()
-}
-
-impl Name {
-    fn from_attrs(
-        source_name: String,
-        ser_name: Attr<String>,
-        de_name: Attr<String>,
-        de_aliases: Option<VecAttr<String>>,
-    ) -> Name {
-        let mut alias_set = BTreeSet::new();
-        if let Some(de_aliases) = de_aliases {
-            for alias_name in de_aliases.get() {
-                alias_set.insert(alias_name);
-            }
-        }
-
-        let ser_name = ser_name.get();
-        let ser_renamed = ser_name.is_some();
-        let de_name = de_name.get();
-        let de_renamed = de_name.is_some();
-        Name {
-            serialize: ser_name.unwrap_or_else(|| source_name.clone()),
-            serialize_renamed: ser_renamed,
-            deserialize: de_name.unwrap_or(source_name),
-            deserialize_renamed: de_renamed,
-            deserialize_aliases: alias_set,
-        }
-    }
-
-    /// Return the container name for the container when serializing.
-    pub fn serialize_name(&self) -> &str {
-        &self.serialize
-    }
-
-    /// Return the container name for the container when deserializing.
-    pub fn deserialize_name(&self) -> &str {
-        &self.deserialize
-    }
-
-    fn deserialize_aliases(&self) -> &BTreeSet<String> {
-        &self.deserialize_aliases
-    }
+fn unraw(ident: &Ident) -> Ident {
+    Ident::new(ident.to_string().trim_start_matches("r#"), ident.span())
 }
 
 #[derive(Copy, Clone)]
@@ -203,7 +154,7 @@ impl RenameAllRules {
 
 /// Represents struct or enum attribute information.
 pub struct Container {
-    name: Name,
+    name: MultiName,
     transparent: bool,
     deny_unknown_fields: bool,
     default: Default,
@@ -327,8 +278,8 @@ impl Container {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_renames(cx, RENAME, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
-                    de_name.set_opt(&meta.path, de.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
+                    de_name.set_opt(&meta.path, de.as_ref().map(Name::from));
                 } else if meta.path == RENAME_ALL {
                     // #[serde(rename_all = "foo")]
                     // #[serde(rename_all(serialize = "foo", deserialize = "bar"))]
@@ -567,7 +518,7 @@ impl Container {
         }
 
         Container {
-            name: Name::from_attrs(unraw(&item.ident), ser_name, de_name, None),
+            name: MultiName::from_attrs(Name::from(&unraw(&item.ident)), ser_name, de_name, None),
             transparent: transparent.get(),
             deny_unknown_fields: deny_unknown_fields.get(),
             default: default.get().unwrap_or(Default::None),
@@ -594,7 +545,7 @@ impl Container {
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
@@ -781,7 +732,7 @@ fn decide_identifier(
 
 /// Represents variant attribute information
 pub struct Variant {
-    name: Name,
+    name: MultiName,
     rename_all_rules: RenameAllRules,
     ser_bound: Option<Vec<syn::WherePredicate>>,
     de_bound: Option<Vec<syn::WherePredicate>>,
@@ -832,15 +783,15 @@ impl Variant {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_multiple_renames(cx, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
                     for de_value in de {
-                        de_name.set_if_none(de_value.value());
-                        de_aliases.insert(&meta.path, de_value.value());
+                        de_name.set_if_none(Name::from(&de_value));
+                        de_aliases.insert(&meta.path, Name::from(&de_value));
                     }
                 } else if meta.path == ALIAS {
                     // #[serde(alias = "foo")]
                     if let Some(s) = get_lit_str(cx, ALIAS, &meta)? {
-                        de_aliases.insert(&meta.path, s.value());
+                        de_aliases.insert(&meta.path, Name::from(&s));
                     }
                 } else if meta.path == RENAME_ALL {
                     // #[serde(rename_all = "foo")]
@@ -947,7 +898,12 @@ impl Variant {
         }
 
         Variant {
-            name: Name::from_attrs(unraw(&variant.ident), ser_name, de_name, Some(de_aliases)),
+            name: MultiName::from_attrs(
+                Name::from(&unraw(&variant.ident)),
+                ser_name,
+                de_name,
+                Some(de_aliases),
+            ),
             rename_all_rules: RenameAllRules {
                 serialize: rename_all_ser_rule.get().unwrap_or(RenameRule::None),
                 deserialize: rename_all_de_rule.get().unwrap_or(RenameRule::None),
@@ -964,20 +920,23 @@ impl Variant {
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
-    pub fn aliases(&self) -> &BTreeSet<String> {
+    pub fn aliases(&self) -> &BTreeSet<Name> {
         self.name.deserialize_aliases()
     }
 
     pub fn rename_by_rules(&mut self, rules: RenameAllRules) {
         if !self.name.serialize_renamed {
-            self.name.serialize = rules.serialize.apply_to_variant(&self.name.serialize);
+            self.name.serialize.value =
+                rules.serialize.apply_to_variant(&self.name.serialize.value);
         }
         if !self.name.deserialize_renamed {
-            self.name.deserialize = rules.deserialize.apply_to_variant(&self.name.deserialize);
+            self.name.deserialize.value = rules
+                .deserialize
+                .apply_to_variant(&self.name.deserialize.value);
         }
         self.name
             .deserialize_aliases
@@ -1023,7 +982,7 @@ impl Variant {
 
 /// Represents field attribute information
 pub struct Field {
-    name: Name,
+    name: MultiName,
     skip_serializing: bool,
     skip_deserializing: bool,
     skip_serializing_if: Option<syn::ExprPath>,
@@ -1082,8 +1041,11 @@ impl Field {
         let mut flatten = BoolAttr::none(cx, FLATTEN);
 
         let ident = match &field.ident {
-            Some(ident) => unraw(ident),
-            None => index.to_string(),
+            Some(ident) => Name::from(&unraw(ident)),
+            None => Name {
+                value: index.to_string(),
+                span: Span::call_site(),
+            },
         };
 
         if let Some(borrow_attribute) = attrs.and_then(|variant| variant.borrow.as_ref()) {
@@ -1119,15 +1081,15 @@ impl Field {
                     // #[serde(rename = "foo")]
                     // #[serde(rename(serialize = "foo", deserialize = "bar"))]
                     let (ser, de) = get_multiple_renames(cx, &meta)?;
-                    ser_name.set_opt(&meta.path, ser.as_ref().map(syn::LitStr::value));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
                     for de_value in de {
-                        de_name.set_if_none(de_value.value());
-                        de_aliases.insert(&meta.path, de_value.value());
+                        de_name.set_if_none(Name::from(&de_value));
+                        de_aliases.insert(&meta.path, Name::from(&de_value));
                     }
                 } else if meta.path == ALIAS {
                     // #[serde(alias = "foo")]
                     if let Some(s) = get_lit_str(cx, ALIAS, &meta)? {
-                        de_aliases.insert(&meta.path, s.value());
+                        de_aliases.insert(&meta.path, Name::from(&s));
                     }
                 } else if meta.path == DEFAULT {
                     if meta.input.peek(Token![=]) {
@@ -1290,7 +1252,7 @@ impl Field {
         }
 
         Field {
-            name: Name::from_attrs(ident, ser_name, de_name, Some(de_aliases)),
+            name: MultiName::from_attrs(ident, ser_name, de_name, Some(de_aliases)),
             skip_serializing: skip_serializing.get(),
             skip_deserializing: skip_deserializing.get(),
             skip_serializing_if: skip_serializing_if.get(),
@@ -1306,20 +1268,22 @@ impl Field {
         }
     }
 
-    pub fn name(&self) -> &Name {
+    pub fn name(&self) -> &MultiName {
         &self.name
     }
 
-    pub fn aliases(&self) -> &BTreeSet<String> {
+    pub fn aliases(&self) -> &BTreeSet<Name> {
         self.name.deserialize_aliases()
     }
 
     pub fn rename_by_rules(&mut self, rules: RenameAllRules) {
         if !self.name.serialize_renamed {
-            self.name.serialize = rules.serialize.apply_to_field(&self.name.serialize);
+            self.name.serialize.value = rules.serialize.apply_to_field(&self.name.serialize.value);
         }
         if !self.name.deserialize_renamed {
-            self.name.deserialize = rules.deserialize.apply_to_field(&self.name.deserialize);
+            self.name.deserialize.value = rules
+                .deserialize
+                .apply_to_field(&self.name.deserialize.value);
         }
         self.name
             .deserialize_aliases
@@ -1769,7 +1733,7 @@ fn is_primitive_path(path: &syn::Path, primitive: &str) -> bool {
 // attribute on the field so there must be at least one borrowable lifetime.
 fn borrowable_lifetimes(
     cx: &Ctxt,
-    name: &str,
+    name: &Name,
     field: &syn::Field,
 ) -> Result<BTreeSet<syn::Lifetime>, ()> {
     let mut lifetimes = BTreeSet::new();

serde_derive/src/internals/check.rs

@@ -329,13 +329,13 @@ fn check_internal_tag_field_name_conflict(cx: &Ctxt, cont: &Container) {
                     let name = field.attrs.name();
                     let ser_name = name.serialize_name();
 
-                    if check_ser && ser_name == tag {
+                    if check_ser && ser_name.value == tag {
                         diagnose_conflict();
                         return;
                     }
 
                     for de_name in field.attrs.aliases() {
-                        if check_de && de_name == tag {
+                        if check_de && de_name.value == tag {
                             diagnose_conflict();
                             return;
                         }

serde_derive/src/internals/mod.rs

@@ -1,5 +1,6 @@
 pub mod ast;
 pub mod attr;
+pub mod name;
 
 mod case;
 mod check;

serde_derive/src/internals/name.rs

@@ -0,0 +1,113 @@
+use crate::internals::attr::{Attr, VecAttr};
+use proc_macro2::{Ident, Span, TokenStream};
+use quote::ToTokens;
+use std::cmp::Ordering;
+use std::collections::BTreeSet;
+use std::fmt::{self, Display};
+use syn::LitStr;
+
+pub struct MultiName {
+    pub(crate) serialize: Name,
+    pub(crate) serialize_renamed: bool,
+    pub(crate) deserialize: Name,
+    pub(crate) deserialize_renamed: bool,
+    pub(crate) deserialize_aliases: BTreeSet<Name>,
+}
+
+impl MultiName {
+    pub(crate) fn from_attrs(
+        source_name: Name,
+        ser_name: Attr<Name>,
+        de_name: Attr<Name>,
+        de_aliases: Option<VecAttr<Name>>,
+    ) -> Self {
+        let mut alias_set = BTreeSet::new();
+        if let Some(de_aliases) = de_aliases {
+            for alias_name in de_aliases.get() {
+                alias_set.insert(alias_name);
+            }
+        }
+
+        let ser_name = ser_name.get();
+        let ser_renamed = ser_name.is_some();
+        let de_name = de_name.get();
+        let de_renamed = de_name.is_some();
+        MultiName {
+            serialize: ser_name.unwrap_or_else(|| source_name.clone()),
+            serialize_renamed: ser_renamed,
+            deserialize: de_name.unwrap_or(source_name),
+            deserialize_renamed: de_renamed,
+            deserialize_aliases: alias_set,
+        }
+    }
+
+    /// Return the container name for the container when serializing.
+    pub fn serialize_name(&self) -> &Name {
+        &self.serialize
+    }
+
+    /// Return the container name for the container when deserializing.
+    pub fn deserialize_name(&self) -> &Name {
+        &self.deserialize
+    }
+
+    pub(crate) fn deserialize_aliases(&self) -> &BTreeSet<Name> {
+        &self.deserialize_aliases
+    }
+}
+
+#[derive(Clone)]
+pub struct Name {
+    pub value: String,
+    pub span: Span,
+}
+
+impl ToTokens for Name {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        LitStr::new(&self.value, self.span).to_tokens(tokens);
+    }
+}
+
+impl Ord for Name {
+    fn cmp(&self, other: &Self) -> Ordering {
+        Ord::cmp(&self.value, &other.value)
+    }
+}
+
+impl PartialOrd for Name {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(Ord::cmp(self, other))
+    }
+}
+
+impl Eq for Name {}
+
+impl PartialEq for Name {
+    fn eq(&self, other: &Self) -> bool {
+        self.value == other.value
+    }
+}
+
+impl From<&Ident> for Name {
+    fn from(ident: &Ident) -> Self {
+        Name {
+            value: ident.to_string(),
+            span: ident.span(),
+        }
+    }
+}
+
+impl From<&LitStr> for Name {
+    fn from(lit: &LitStr) -> Self {
+        Name {
+            value: lit.value(),
+            span: lit.span(),
+        }
+    }
+}
+
+impl Display for Name {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        Display::fmt(&self.value, formatter)
+    }
+}

serde_derive/src/lib.rs

@@ -13,7 +13,7 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.211")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.215")]
 #![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
 // Ignored clippy lints
 #![allow(

serde_derive/src/ser.rs

@@ -1,5 +1,6 @@
 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 proc_macro2::{Span, TokenStream};
@@ -798,9 +799,9 @@ fn serialize_untagged_variant(
 
 enum TupleVariant<'a> {
     ExternallyTagged {
-        type_name: &'a str,
+        type_name: &'a Name,
         variant_index: u32,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     Untagged,
 }
@@ -867,11 +868,11 @@ fn serialize_tuple_variant(
 enum StructVariant<'a> {
     ExternallyTagged {
         variant_index: u32,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     InternallyTagged {
         tag: &'a str,
-        variant_name: &'a str,
+        variant_name: &'a Name,
     },
     Untagged,
 }
@@ -880,7 +881,7 @@ fn serialize_struct_variant(
     context: StructVariant,
     params: &Parameters,
     fields: &[Field],
-    name: &str,
+    name: &Name,
 ) -> Fragment {
     if fields.iter().any(|field| field.attrs.flatten()) {
         return serialize_struct_variant_with_flatten(context, params, fields, name);
@@ -964,7 +965,7 @@ fn serialize_struct_variant_with_flatten(
     context: StructVariant,
     params: &Parameters,
     fields: &[Field],
-    name: &str,
+    name: &Name,
 ) -> Fragment {
     let struct_trait = StructTrait::SerializeMap;
     let serialize_fields = serialize_struct_visitor(fields, params, true, &struct_trait);
@@ -1220,12 +1221,15 @@ fn wrap_serialize_with(
         })
     });
 
+    let self_var = quote!(self);
+    let serializer_var = quote!(__s);
+
     // If #serialize_with returns wrong type, error will be reported on here.
     // We attach span of the path to this piece so error will be reported
     // on the #[serde(with = "...")]
     //                       ^^^^^
     let wrapper_serialize = quote_spanned! {serialize_with.span()=>
-        #serialize_with(#(self.values.#field_access, )* __s)
+        #serialize_with(#(#self_var.values.#field_access, )* #serializer_var)
     };
 
     quote!({
@@ -1236,7 +1240,7 @@ fn wrap_serialize_with(
         }
 
         impl #wrapper_impl_generics _serde::Serialize for __SerializeWith #wrapper_ty_generics #where_clause {
-            fn serialize<__S>(&self, __s: __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,
             {

test_suite/tests/regression/issue2565.rs

@@ -1,4 +1,4 @@
-use serde_derive::{Serialize, Deserialize};
+use serde_derive::{Deserialize, Serialize};
 use serde_test::{assert_tokens, Token};
 
 #[derive(Serialize, Deserialize, Debug, PartialEq)]
@@ -18,11 +18,15 @@ fn simple_variant() {
     assert_tokens(
         &Enum::Simple { a: 42 },
         &[
-            Token::StructVariant { name: "Enum", variant: "Simple", len: 1 },
+            Token::StructVariant {
+                name: "Enum",
+                variant: "Simple",
+                len: 1,
+            },
             Token::Str("a"),
             Token::I32(42),
             Token::StructVariantEnd,
-        ]
+        ],
     );
 }
 
@@ -31,11 +35,14 @@ fn flatten_variant() {
     assert_tokens(
         &Enum::Flatten { flatten: (), a: 42 },
         &[
-            Token::NewtypeVariant { name: "Enum", variant: "Flatten" },
+            Token::NewtypeVariant {
+                name: "Enum",
+                variant: "Flatten",
+            },
             Token::Map { len: None },
             Token::Str("a"),
             Token::I32(42),
             Token::MapEnd,
-        ]
+        ],
     );
 }

test_suite/tests/regression/issue2844.rs

@@ -0,0 +1,33 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+
+use serde_derive::{Deserialize, Serialize};
+
+macro_rules! declare_in_macro {
+    ($with:literal) => {
+        #[derive(Serialize, Deserialize)]
+        pub struct S {
+            #[serde(with = $with)]
+            f: i32,
+        }
+    };
+}
+
+declare_in_macro!("with");
+
+mod with {
+    use serde::{Deserializer, Serializer};
+
+    pub fn serialize<S>(_: &i32, _: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        unimplemented!()
+    }
+
+    pub fn deserialize<'de, D>(_: D) -> Result<i32, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        unimplemented!()
+    }
+}

test_suite/tests/regression/issue2846.rs

@@ -0,0 +1,27 @@
+#![allow(clippy::trivially_copy_pass_by_ref)]
+
+use serde_derive::Deserialize;
+
+macro_rules! declare_in_macro {
+    ($with:literal) => {
+        #[derive(Deserialize)]
+        pub struct S(
+            #[serde(with = $with)]
+            #[allow(dead_code)]
+            i32,
+        );
+    };
+}
+
+declare_in_macro!("with");
+
+mod with {
+    use serde::Deserializer;
+
+    pub fn deserialize<'de, D>(_: D) -> Result<i32, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        unimplemented!()
+    }
+}

test_suite/tests/ui/conflict/alias-enum.rs

@@ -0,0 +1,75 @@
+#![allow(non_camel_case_types)]
+
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+enum E {
+    S1 {
+        #[serde(alias = "a", alias = "b", alias = "c")]
+        a: (),
+
+        // Warning on "c" and "b"
+        #[serde(alias = "c")]
+        b: (),
+
+        #[serde(skip_deserializing)]
+        c: (),
+    },
+
+    S2 {
+        #[serde(alias = "b", alias = "c")]
+        a: (),
+
+        // Warning on "c"
+        #[serde(rename = "c")]
+        b: (),
+    },
+
+    #[serde(rename_all = "UPPERCASE")]
+    S3 {
+        #[serde(alias = "B", alias = "c")]
+        a: (),
+
+        // Warning on "b" because this collides with the "B" above after
+        // applying rename rules
+        b: (),
+    },
+}
+
+#[derive(Deserialize)]
+enum E1 {
+    #[serde(alias = "a", alias = "b", alias = "c")]
+    a,
+
+    // Warning on "c" and "b"
+    #[serde(alias = "c")]
+    b,
+
+    #[serde(skip_deserializing)]
+    c,
+}
+
+#[derive(Deserialize)]
+enum E2 {
+    #[serde(alias = "b", alias = "c")]
+    a,
+
+    // Warning on "c"
+    #[serde(rename = "c")]
+    b,
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "UPPERCASE")]
+enum E3 {
+    #[serde(alias = "B", alias = "c")]
+    a,
+
+    // Warning on "b" because this collides with the "B" above after applying
+    // rename rules
+    b,
+}
+
+fn main() {
+    __FAIL__;
+}

test_suite/tests/ui/conflict/alias-enum.stderr

@@ -0,0 +1,79 @@
+error[E0425]: cannot find value `__FAIL__` in this scope
+  --> tests/ui/conflict/alias-enum.rs:74:5
+   |
+74 |     __FAIL__;
+   |     ^^^^^^^^ not found in this scope
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:13:9
+   |
+8  |         #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                      --- matches all the relevant values
+...
+13 |         b: (),
+   |         ^ no value can reach this
+   |
+   = note: `#[warn(unreachable_patterns)]` on by default
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:12:25
+   |
+8  |         #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                                   --- matches all the relevant values
+...
+12 |         #[serde(alias = "c")]
+   |                         ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:24:26
+   |
+20 |         #[serde(alias = "b", alias = "c")]
+   |                                      --- matches all the relevant values
+...
+24 |         #[serde(rename = "c")]
+   |                          ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:35:9
+   |
+30 |         #[serde(alias = "B", alias = "c")]
+   |                         --- matches all the relevant values
+...
+35 |         b: (),
+   |         ^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:46:5
+   |
+41 |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+46 |     b,
+   |     ^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:45:21
+   |
+41 |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                               --- matches all the relevant values
+...
+45 |     #[serde(alias = "c")]
+   |                     ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:58:22
+   |
+54 |     #[serde(alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+58 |     #[serde(rename = "c")]
+   |                      ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias-enum.rs:70:5
+   |
+65 |     #[serde(alias = "B", alias = "c")]
+   |                     --- matches all the relevant values
+...
+70 |     b,
+   |     ^ no value can reach this

test_suite/tests/ui/conflict/alias.rs

@@ -0,0 +1,39 @@
+use serde_derive::Deserialize;
+
+#[derive(Deserialize)]
+struct S1 {
+    #[serde(alias = "a", alias = "b", alias = "c")]
+    a: (),
+
+    // Warning on "c" and "b"
+    #[serde(alias = "c")]
+    b: (),
+
+    #[serde(skip_deserializing)]
+    c: (),
+}
+
+#[derive(Deserialize)]
+struct S2 {
+    #[serde(alias = "b", alias = "c")]
+    a: (),
+
+    // Warning on "c"
+    #[serde(rename = "c")]
+    b: (),
+}
+
+#[derive(Deserialize)]
+#[serde(rename_all = "UPPERCASE")]
+struct S3 {
+    #[serde(alias = "B", alias = "c")]
+    a: (),
+
+    // Warning on "b" because this collides with the "B" above after applying
+    // rename rules
+    b: (),
+}
+
+fn main() {
+    __FAIL__;
+}

test_suite/tests/ui/conflict/alias.stderr

@@ -0,0 +1,43 @@
+error[E0425]: cannot find value `__FAIL__` in this scope
+  --> tests/ui/conflict/alias.rs:38:5
+   |
+38 |     __FAIL__;
+   |     ^^^^^^^^ not found in this scope
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:10:5
+   |
+5  |     #[serde(alias = "a", alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+10 |     b: (),
+   |     ^ no value can reach this
+   |
+   = note: `#[warn(unreachable_patterns)]` on by default
+
+warning: unreachable pattern
+ --> tests/ui/conflict/alias.rs:9:21
+  |
+5 |     #[serde(alias = "a", alias = "b", alias = "c")]
+  |                                               --- matches all the relevant values
+...
+9 |     #[serde(alias = "c")]
+  |                     ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:22:22
+   |
+18 |     #[serde(alias = "b", alias = "c")]
+   |                                  --- matches all the relevant values
+...
+22 |     #[serde(rename = "c")]
+   |                      ^^^ no value can reach this
+
+warning: unreachable pattern
+  --> tests/ui/conflict/alias.rs:34:5
+   |
+29 |     #[serde(alias = "B", alias = "c")]
+   |                     --- matches all the relevant values
+...
+34 |     b: (),
+   |     ^ no value can reach this

test_suite/tests/ui/with/incorrect_type.stderr

@@ -19,8 +19,10 @@ note: required by a bound in `w::serialize`
 error[E0061]: this function takes 1 argument but 2 arguments were supplied
   --> tests/ui/with/incorrect_type.rs:15:25
    |
+14 | #[derive(Serialize, Deserialize)]
+   |          --------- unexpected argument #2 of type `__S`
 15 | struct W(#[serde(with = "w")] u8, u8);
-   |                         ^^^ unexpected argument #2 of type `__S`
+   |                         ^^^
    |
 note: function defined here
   --> tests/ui/with/incorrect_type.rs:9:12
@@ -68,8 +70,10 @@ note: required by a bound in `w::serialize`
 error[E0061]: this function takes 1 argument but 2 arguments were supplied
   --> tests/ui/with/incorrect_type.rs:18:35
    |
+17 | #[derive(Serialize, Deserialize)]
+   |          --------- unexpected argument #2 of type `__S`
 18 | struct S(#[serde(serialize_with = "w::serialize")] u8, u8);
-   |                                   ^^^^^^^^^^^^^^ unexpected argument #2 of type `__S`
+   |                                   ^^^^^^^^^^^^^^
    |
 note: function defined here
   --> tests/ui/with/incorrect_type.rs:9:12