Merge pull request #2855 from dtolnay/namespan

Produce unreachable_patterns warning when deserialization names collide

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};
@@ -2002,7 +2003,7 @@ fn deserialize_untagged_newtype_variant(
 
 struct FieldWithAliases<'a> {
     ident: Ident,
-    aliases: &'a BTreeSet<String>,
+    aliases: &'a BTreeSet<Name>,
 }
 
 fn deserialize_generated_identifier(
@@ -2224,7 +2225,7 @@ fn deserialize_identifier(
         let aliases = field
             .aliases
             .iter()
-            .map(|alias| Literal::byte_string(alias.as_bytes()));
+            .map(|alias| Literal::byte_string(alias.value.as_bytes()));
         quote!(#(#aliases)|* => _serde::__private::Ok(#this_value::#ident))
     });
 

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 {
+fn unraw(ident: &Ident) -> Ident {
-    serialize: String,
+    Ident::new(ident.to_string().trim_start_matches("r#"), ident.span())
-    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
-    }
 }
 
 #[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));
+                    ser_name.set_opt(&meta.path, ser.as_ref().map(Name::from));
-                    de_name.set_opt(&meta.path, de.as_ref().map(syn::LitStr::value));
+                    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_name.set_if_none(Name::from(&de_value));
-                        de_aliases.insert(&meta.path, de_value.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),
+            Some(ident) => Name::from(&unraw(ident)),
-            None => index.to_string(),
+            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_name.set_if_none(Name::from(&de_value));
-                        de_aliases.insert(&meta.path, de_value.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

@@ -332,13 +332,13 @@ 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/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);