From c1259fbc87379ae65605a5c2a09efb355e2349e4 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Wed, 10 May 2017 19:56:05 -0700
Subject: [PATCH] Support borrowing within internally tagged enum

---
 serde/src/private/de.rs         | 284 +++++++++++++++++++-------------
 test_suite/tests/test_macros.rs |  24 +++
 2 files changed, 195 insertions(+), 113 deletions(-)

diff --git a/serde/src/private/de.rs b/serde/src/private/de.rs
index 45b383fb..2c5648cd 100644
--- a/serde/src/private/de.rs
+++ b/serde/src/private/de.rs
@@ -233,7 +233,7 @@ mod content {
     ///
     /// Not public API. Use serde-value instead.
     #[derive(Debug)]
-    pub enum Content {
+    pub enum Content<'de> {
         Bool(bool),
 
         U8(u8),
@@ -251,18 +251,20 @@ mod content {
 
         Char(char),
         String(String),
-        Bytes(Vec<u8>),
+        Str(&'de str),
+        ByteBuf(Vec<u8>),
+        Bytes(&'de [u8]),
 
         None,
-        Some(Box<Content>),
+        Some(Box<Content<'de>>),
 
         Unit,
-        Newtype(Box<Content>),
-        Seq(Vec<Content>),
-        Map(Vec<(Content, Content)>),
+        Newtype(Box<Content<'de>>),
+        Seq(Vec<Content<'de>>),
+        Map(Vec<(Content<'de>, Content<'de>)>),
     }
 
-    impl Content {
+    impl<'de> Content<'de> {
         fn unexpected(&self) -> Unexpected {
             match *self {
                 Content::Bool(b) => Unexpected::Bool(b),
@@ -278,7 +280,9 @@ mod content {
                 Content::F64(f) => Unexpected::Float(f),
                 Content::Char(c) => Unexpected::Char(c),
                 Content::String(ref s) => Unexpected::Str(s),
-                Content::Bytes(ref b) => Unexpected::Bytes(b),
+                Content::Str(s) => Unexpected::Str(s),
+                Content::ByteBuf(ref b) => Unexpected::Bytes(b),
+                Content::Bytes(b) => Unexpected::Bytes(b),
                 Content::None | Content::Some(_) => Unexpected::Option,
                 Content::Unit => Unexpected::Unit,
                 Content::Newtype(_) => Unexpected::NewtypeStruct,
@@ -288,21 +292,30 @@ mod content {
         }
     }
 
-    impl<'de> Deserialize<'de> for Content {
+    impl<'de> Deserialize<'de> for Content<'de> {
         fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where
             D: Deserializer<'de>,
         {
             // Untagged and internally tagged enums are only supported in
             // self-describing formats.
-            deserializer.deserialize_any(ContentVisitor)
+            let visitor = ContentVisitor { value: PhantomData };
+            deserializer.deserialize_any(visitor)
         }
     }
 
-    struct ContentVisitor;
+    struct ContentVisitor<'de> {
+        value: PhantomData<Content<'de>>,
+    }
 
-    impl<'de> Visitor<'de> for ContentVisitor {
-        type Value = Content;
+    impl<'de> ContentVisitor<'de> {
+        fn new() -> Self {
+            ContentVisitor { value: PhantomData }
+        }
+    }
+
+    impl<'de> Visitor<'de> for ContentVisitor<'de> {
+        type Value = Content<'de>;
 
         fn expecting(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
             fmt.write_str("any value")
@@ -399,6 +412,13 @@ mod content {
             Ok(Content::String(value.into()))
         }
 
+        fn visit_borrowed_str<F>(self, value: &'de str) -> Result<Self::Value, F>
+        where
+            F: de::Error,
+        {
+            Ok(Content::Str(value))
+        }
+
         fn visit_string<F>(self, value: String) -> Result<Self::Value, F>
         where
             F: de::Error,
@@ -410,14 +430,21 @@ mod content {
         where
             F: de::Error,
         {
-            Ok(Content::Bytes(value.into()))
+            Ok(Content::ByteBuf(value.into()))
+        }
+
+        fn visit_borrowed_bytes<F>(self, value: &'de [u8]) -> Result<Self::Value, F>
+        where
+            F: de::Error,
+        {
+            Ok(Content::Bytes(value))
         }
 
         fn visit_byte_buf<F>(self, value: Vec<u8>) -> Result<Self::Value, F>
         where
             F: de::Error,
         {
-            Ok(Content::Bytes(value))
+            Ok(Content::ByteBuf(value))
         }
 
         fn visit_unit<F>(self) -> Result<Self::Value, F>
@@ -481,23 +508,24 @@ mod content {
     /// This is the type of the map keys in an internally tagged enum.
     ///
     /// Not public API.
-    pub enum TagOrContent {
+    pub enum TagOrContent<'de> {
         Tag,
-        Content(Content),
+        Content(Content<'de>),
     }
 
-    struct TagOrContentVisitor {
+    struct TagOrContentVisitor<'de> {
         name: &'static str,
+        value: PhantomData<TagOrContent<'de>>,
     }
 
-    impl TagOrContentVisitor {
+    impl<'de> TagOrContentVisitor<'de> {
         fn new(name: &'static str) -> Self {
-            TagOrContentVisitor { name: name }
+            TagOrContentVisitor { name: name, value: PhantomData }
         }
     }
 
-    impl<'de> DeserializeSeed<'de> for TagOrContentVisitor {
-        type Value = TagOrContent;
+    impl<'de> DeserializeSeed<'de> for TagOrContentVisitor<'de> {
+        type Value = TagOrContent<'de>;
 
         fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where
@@ -509,8 +537,8 @@ mod content {
         }
     }
 
-    impl<'de> Visitor<'de> for TagOrContentVisitor {
-        type Value = TagOrContent;
+    impl<'de> Visitor<'de> for TagOrContentVisitor<'de> {
+        type Value = TagOrContent<'de>;
 
         fn expecting(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
             write!(fmt, "a type tag `{}` or any other value", self.name)
@@ -520,7 +548,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_bool(value)
                 .map(TagOrContent::Content)
         }
@@ -529,14 +557,14 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor.visit_i8(value).map(TagOrContent::Content)
+            ContentVisitor::new().visit_i8(value).map(TagOrContent::Content)
         }
 
         fn visit_i16<F>(self, value: i16) -> Result<Self::Value, F>
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_i16(value)
                 .map(TagOrContent::Content)
         }
@@ -545,7 +573,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_i32(value)
                 .map(TagOrContent::Content)
         }
@@ -554,7 +582,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_i64(value)
                 .map(TagOrContent::Content)
         }
@@ -563,14 +591,14 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor.visit_u8(value).map(TagOrContent::Content)
+            ContentVisitor::new().visit_u8(value).map(TagOrContent::Content)
         }
 
         fn visit_u16<F>(self, value: u16) -> Result<Self::Value, F>
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_u16(value)
                 .map(TagOrContent::Content)
         }
@@ -579,7 +607,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_u32(value)
                 .map(TagOrContent::Content)
         }
@@ -588,7 +616,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_u64(value)
                 .map(TagOrContent::Content)
         }
@@ -597,7 +625,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_f32(value)
                 .map(TagOrContent::Content)
         }
@@ -606,7 +634,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_f64(value)
                 .map(TagOrContent::Content)
         }
@@ -615,7 +643,7 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_char(value)
                 .map(TagOrContent::Content)
         }
@@ -627,12 +655,25 @@ mod content {
             if value == self.name {
                 Ok(TagOrContent::Tag)
             } else {
-                ContentVisitor
+                ContentVisitor::new()
                     .visit_str(value)
                     .map(TagOrContent::Content)
             }
         }
 
+        fn visit_borrowed_str<F>(self, value: &'de str) -> Result<Self::Value, F>
+        where
+            F: de::Error,
+        {
+            if value == self.name {
+                Ok(TagOrContent::Tag)
+            } else {
+                ContentVisitor::new()
+                    .visit_borrowed_str(value)
+                    .map(TagOrContent::Content)
+            }
+        }
+
         fn visit_string<F>(self, value: String) -> Result<Self::Value, F>
         where
             F: de::Error,
@@ -640,7 +681,7 @@ mod content {
             if value == self.name {
                 Ok(TagOrContent::Tag)
             } else {
-                ContentVisitor
+                ContentVisitor::new()
                     .visit_string(value)
                     .map(TagOrContent::Content)
             }
@@ -653,12 +694,25 @@ mod content {
             if value == self.name.as_bytes() {
                 Ok(TagOrContent::Tag)
             } else {
-                ContentVisitor
+                ContentVisitor::new()
                     .visit_bytes(value)
                     .map(TagOrContent::Content)
             }
         }
 
+        fn visit_borrowed_bytes<F>(self, value: &'de [u8]) -> Result<Self::Value, F>
+        where
+            F: de::Error,
+        {
+            if value == self.name.as_bytes() {
+                Ok(TagOrContent::Tag)
+            } else {
+                ContentVisitor::new()
+                    .visit_borrowed_bytes(value)
+                    .map(TagOrContent::Content)
+            }
+        }
+
         fn visit_byte_buf<F>(self, value: Vec<u8>) -> Result<Self::Value, F>
         where
             F: de::Error,
@@ -666,7 +720,7 @@ mod content {
             if value == self.name.as_bytes() {
                 Ok(TagOrContent::Tag)
             } else {
-                ContentVisitor
+                ContentVisitor::new()
                     .visit_byte_buf(value)
                     .map(TagOrContent::Content)
             }
@@ -676,21 +730,21 @@ mod content {
         where
             F: de::Error,
         {
-            ContentVisitor.visit_unit().map(TagOrContent::Content)
+            ContentVisitor::new().visit_unit().map(TagOrContent::Content)
         }
 
         fn visit_none<F>(self) -> Result<Self::Value, F>
         where
             F: de::Error,
         {
-            ContentVisitor.visit_none().map(TagOrContent::Content)
+            ContentVisitor::new().visit_none().map(TagOrContent::Content)
         }
 
         fn visit_some<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where
             D: Deserializer<'de>,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_some(deserializer)
                 .map(TagOrContent::Content)
         }
@@ -699,7 +753,7 @@ mod content {
         where
             D: Deserializer<'de>,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_newtype_struct(deserializer)
                 .map(TagOrContent::Content)
         }
@@ -708,7 +762,7 @@ mod content {
         where
             V: SeqAccess<'de>,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_seq(visitor)
                 .map(TagOrContent::Content)
         }
@@ -717,7 +771,7 @@ mod content {
         where
             V: MapAccess<'de>,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_map(visitor)
                 .map(TagOrContent::Content)
         }
@@ -726,7 +780,7 @@ mod content {
         where
             V: EnumAccess<'de>,
         {
-            ContentVisitor
+            ContentVisitor::new()
                 .visit_enum(visitor)
                 .map(TagOrContent::Content)
         }
@@ -735,33 +789,33 @@ mod content {
     /// Used by generated code to deserialize an internally tagged enum.
     ///
     /// Not public API.
-    pub struct TaggedContent<T> {
+    pub struct TaggedContent<'de, T> {
         pub tag: T,
-        pub content: Content,
+        pub content: Content<'de>,
     }
 
     /// Not public API.
-    pub struct TaggedContentVisitor<T> {
+    pub struct TaggedContentVisitor<'de, T> {
         tag_name: &'static str,
-        tag: PhantomData<T>,
+        value: PhantomData<TaggedContent<'de, T>>,
     }
 
-    impl<T> TaggedContentVisitor<T> {
+    impl<'de, T> TaggedContentVisitor<'de, T> {
         /// Visitor for the content of an internally tagged enum with the given tag
         /// name.
         pub fn new(name: &'static str) -> Self {
             TaggedContentVisitor {
                 tag_name: name,
-                tag: PhantomData,
+                value: PhantomData,
             }
         }
     }
 
-    impl<'de, T> DeserializeSeed<'de> for TaggedContentVisitor<T>
+    impl<'de, T> DeserializeSeed<'de> for TaggedContentVisitor<'de, T>
     where
         T: Deserialize<'de>,
     {
-        type Value = TaggedContent<T>;
+        type Value = TaggedContent<'de, T>;
 
         fn deserialize<D>(self, deserializer: D) -> Result<Self::Value, D::Error>
         where
@@ -773,11 +827,11 @@ mod content {
         }
     }
 
-    impl<'de, T> Visitor<'de> for TaggedContentVisitor<T>
+    impl<'de, T> Visitor<'de> for TaggedContentVisitor<'de, T>
     where
         T: Deserialize<'de>,
     {
-        type Value = TaggedContent<T>;
+        type Value = TaggedContent<'de, T>;
 
         fn expecting(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
             fmt.write_str("any value")
@@ -913,14 +967,14 @@ mod content {
     }
 
     /// Not public API
-    pub struct ContentDeserializer<E> {
-        content: Content,
+    pub struct ContentDeserializer<'de, E> {
+        content: Content<'de>,
         err: PhantomData<E>,
     }
 
     /// Used when deserializing an internally tagged enum because the content will
     /// be used exactly once.
-    impl<'de, E> Deserializer<'de> for ContentDeserializer<E>
+    impl<'de, E> Deserializer<'de> for ContentDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -944,6 +998,9 @@ mod content {
                 Content::F64(v) => visitor.visit_f64(v),
                 Content::Char(v) => visitor.visit_char(v),
                 Content::String(v) => visitor.visit_string(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(v) => visitor.visit_byte_buf(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
                 Content::Unit => visitor.visit_unit(),
                 Content::None => visitor.visit_none(),
                 Content::Some(v) => visitor.visit_some(ContentDeserializer::new(*v)),
@@ -965,7 +1022,6 @@ mod content {
                     try!(map_visitor.end());
                     Ok(value)
                 }
-                Content::Bytes(v) => visitor.visit_byte_buf(v),
             }
         }
 
@@ -1048,9 +1104,9 @@ mod content {
         }
     }
 
-    impl<E> ContentDeserializer<E> {
+    impl<'de, E> ContentDeserializer<'de, E> {
         /// private API, don't use
-        pub fn new(content: Content) -> Self {
+        pub fn new(content: Content<'de>) -> Self {
             ContentDeserializer {
                 content: content,
                 err: PhantomData,
@@ -1058,21 +1114,21 @@ mod content {
         }
     }
 
-    struct EnumDeserializer<E>
+    struct EnumDeserializer<'de, E>
     where
         E: de::Error,
     {
-        variant: Content,
-        value: Option<Content>,
+        variant: Content<'de>,
+        value: Option<Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<'de, E> de::EnumAccess<'de> for EnumDeserializer<E>
+    impl<'de, E> de::EnumAccess<'de> for EnumDeserializer<'de, E>
     where
         E: de::Error,
     {
         type Error = E;
-        type Variant = VariantDeserializer<Self::Error>;
+        type Variant = VariantDeserializer<'de, Self::Error>;
 
         fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant), E>
         where
@@ -1087,15 +1143,15 @@ mod content {
         }
     }
 
-    struct VariantDeserializer<E>
+    struct VariantDeserializer<'de, E>
     where
         E: de::Error,
     {
-        value: Option<Content>,
+        value: Option<Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<'de, E> de::VariantAccess<'de> for VariantDeserializer<E>
+    impl<'de, E> de::VariantAccess<'de> for VariantDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1151,19 +1207,19 @@ mod content {
         }
     }
 
-    struct SeqDeserializer<E>
+    struct SeqDeserializer<'de, E>
     where
         E: de::Error,
     {
-        iter: <Vec<Content> as IntoIterator>::IntoIter,
+        iter: <Vec<Content<'de>> as IntoIterator>::IntoIter,
         err: PhantomData<E>,
     }
 
-    impl<E> SeqDeserializer<E>
+    impl<'de, E> SeqDeserializer<'de, E>
     where
         E: de::Error,
     {
-        fn new(vec: Vec<Content>) -> Self {
+        fn new(vec: Vec<Content<'de>>) -> Self {
             SeqDeserializer {
                 iter: vec.into_iter(),
                 err: PhantomData,
@@ -1171,7 +1227,7 @@ mod content {
         }
     }
 
-    impl<'de, E> de::Deserializer<'de> for SeqDeserializer<E>
+    impl<'de, E> de::Deserializer<'de> for SeqDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1203,7 +1259,7 @@ mod content {
         }
     }
 
-    impl<'de, E> de::SeqAccess<'de> for SeqDeserializer<E>
+    impl<'de, E> de::SeqAccess<'de> for SeqDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1227,20 +1283,20 @@ mod content {
         }
     }
 
-    struct MapDeserializer<E>
+    struct MapDeserializer<'de, E>
     where
         E: de::Error,
     {
-        iter: <Vec<(Content, Content)> as IntoIterator>::IntoIter,
-        value: Option<Content>,
+        iter: <Vec<(Content<'de>, Content<'de>)> as IntoIterator>::IntoIter,
+        value: Option<Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<E> MapDeserializer<E>
+    impl<'de, E> MapDeserializer<'de, E>
     where
         E: de::Error,
     {
-        fn new(map: Vec<(Content, Content)>) -> Self {
+        fn new(map: Vec<(Content<'de>, Content<'de>)>) -> Self {
             MapDeserializer {
                 iter: map.into_iter(),
                 value: None,
@@ -1249,7 +1305,7 @@ mod content {
         }
     }
 
-    impl<'de, E> de::MapAccess<'de> for MapDeserializer<E>
+    impl<'de, E> de::MapAccess<'de> for MapDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1283,7 +1339,7 @@ mod content {
         }
     }
 
-    impl<'de, E> de::Deserializer<'de> for MapDeserializer<E>
+    impl<'de, E> de::Deserializer<'de> for MapDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1305,14 +1361,14 @@ mod content {
     }
 
     /// Not public API.
-    pub struct ContentRefDeserializer<'a, E> {
-        content: &'a Content,
+    pub struct ContentRefDeserializer<'a, 'de: 'a, E> {
+        content: &'a Content<'de>,
         err: PhantomData<E>,
     }
 
     /// Used when deserializing an untagged enum because the content may need to be
     /// used more than once.
-    impl<'de, 'a, E> Deserializer<'de> for ContentRefDeserializer<'a, E>
+    impl<'de, 'a, E> Deserializer<'de> for ContentRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1336,6 +1392,9 @@ mod content {
                 Content::F64(v) => visitor.visit_f64(v),
                 Content::Char(v) => visitor.visit_char(v),
                 Content::String(ref v) => visitor.visit_str(v),
+                Content::Str(v) => visitor.visit_borrowed_str(v),
+                Content::ByteBuf(ref v) => visitor.visit_bytes(v),
+                Content::Bytes(v) => visitor.visit_borrowed_bytes(v),
                 Content::Unit => visitor.visit_unit(),
                 Content::None => visitor.visit_none(),
                 Content::Some(ref v) => visitor.visit_some(ContentRefDeserializer::new(v)),
@@ -1361,7 +1420,6 @@ mod content {
                     try!(map_visitor.end());
                     Ok(value)
                 }
-                Content::Bytes(ref v) => visitor.visit_bytes(v),
             }
         }
 
@@ -1440,9 +1498,9 @@ mod content {
         }
     }
 
-    impl<'a, E> ContentRefDeserializer<'a, E> {
+    impl<'a, 'de, E> ContentRefDeserializer<'a, 'de, E> {
         /// private API, don't use
-        pub fn new(content: &'a Content) -> Self {
+        pub fn new(content: &'a Content<'de>) -> Self {
             ContentRefDeserializer {
                 content: content,
                 err: PhantomData,
@@ -1450,21 +1508,21 @@ mod content {
         }
     }
 
-    struct EnumRefDeserializer<'a, E>
+    struct EnumRefDeserializer<'a, 'de: 'a, E>
     where
         E: de::Error,
     {
-        variant: &'a Content,
-        value: Option<&'a Content>,
+        variant: &'a Content<'de>,
+        value: Option<&'a Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<'de, 'a, E> de::EnumAccess<'de> for EnumRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::EnumAccess<'de> for EnumRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
         type Error = E;
-        type Variant = VariantRefDeserializer<'a, Self::Error>;
+        type Variant = VariantRefDeserializer<'a, 'de, Self::Error>;
 
         fn variant_seed<V>(self, seed: V) -> Result<(V::Value, Self::Variant), Self::Error>
         where
@@ -1479,15 +1537,15 @@ mod content {
         }
     }
 
-    struct VariantRefDeserializer<'a, E>
+    struct VariantRefDeserializer<'a, 'de: 'a, E>
     where
         E: de::Error,
     {
-        value: Option<&'a Content>,
+        value: Option<&'a Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<'de, 'a, E> de::VariantAccess<'de> for VariantRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::VariantAccess<'de> for VariantRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1543,19 +1601,19 @@ mod content {
         }
     }
 
-    struct SeqRefDeserializer<'a, E>
+    struct SeqRefDeserializer<'a, 'de: 'a, E>
     where
         E: de::Error,
     {
-        iter: <&'a [Content] as IntoIterator>::IntoIter,
+        iter: <&'a [Content<'de>] as IntoIterator>::IntoIter,
         err: PhantomData<E>,
     }
 
-    impl<'a, E> SeqRefDeserializer<'a, E>
+    impl<'a, 'de, E> SeqRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
-        fn new(vec: &'a [Content]) -> Self {
+        fn new(vec: &'a [Content<'de>]) -> Self {
             SeqRefDeserializer {
                 iter: vec.into_iter(),
                 err: PhantomData,
@@ -1563,7 +1621,7 @@ mod content {
         }
     }
 
-    impl<'de, 'a, E> de::Deserializer<'de> for SeqRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::Deserializer<'de> for SeqRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1595,7 +1653,7 @@ mod content {
         }
     }
 
-    impl<'de, 'a, E> de::SeqAccess<'de> for SeqRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::SeqAccess<'de> for SeqRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1619,20 +1677,20 @@ mod content {
         }
     }
 
-    struct MapRefDeserializer<'a, E>
+    struct MapRefDeserializer<'a, 'de: 'a, E>
     where
         E: de::Error,
     {
-        iter: <&'a [(Content, Content)] as IntoIterator>::IntoIter,
-        value: Option<&'a Content>,
+        iter: <&'a [(Content<'de>, Content<'de>)] as IntoIterator>::IntoIter,
+        value: Option<&'a Content<'de>>,
         err: PhantomData<E>,
     }
 
-    impl<'a, E> MapRefDeserializer<'a, E>
+    impl<'a, 'de, E> MapRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
-        fn new(map: &'a [(Content, Content)]) -> Self {
+        fn new(map: &'a [(Content<'de>, Content<'de>)]) -> Self {
             MapRefDeserializer {
                 iter: map.into_iter(),
                 value: None,
@@ -1641,7 +1699,7 @@ mod content {
         }
     }
 
-    impl<'de, 'a, E> de::MapAccess<'de> for MapRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::MapAccess<'de> for MapRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1676,7 +1734,7 @@ mod content {
         }
     }
 
-    impl<'de, 'a, E> de::Deserializer<'de> for MapRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::Deserializer<'de> for MapRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
@@ -1697,7 +1755,7 @@ mod content {
         }
     }
 
-    impl<'de, E> de::IntoDeserializer<'de, E> for ContentDeserializer<E>
+    impl<'de, E> de::IntoDeserializer<'de, E> for ContentDeserializer<'de, E>
     where
         E: de::Error,
     {
@@ -1708,7 +1766,7 @@ mod content {
         }
     }
 
-    impl<'de, 'a, E> de::IntoDeserializer<'de, E> for ContentRefDeserializer<'a, E>
+    impl<'de, 'a, E> de::IntoDeserializer<'de, E> for ContentRefDeserializer<'a, 'de, E>
     where
         E: de::Error,
     {
diff --git a/test_suite/tests/test_macros.rs b/test_suite/tests/test_macros.rs
index 6c7e4b2a..651bcfea 100644
--- a/test_suite/tests/test_macros.rs
+++ b/test_suite/tests/test_macros.rs
@@ -695,6 +695,30 @@ fn test_internally_tagged_enum() {
     );
 }
 
+#[test]
+fn test_internally_tagged_borrow() {
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    #[serde(tag = "type")]
+    pub enum Input<'a> {
+        Package { name: &'a str },
+    }
+
+    assert_tokens(
+        &Input::Package { name: "borrowed" },
+        &[
+            Token::Struct { name: "Input", len: 2 },
+
+            Token::BorrowedStr("type"),
+            Token::BorrowedStr("Package"),
+
+            Token::BorrowedStr("name"),
+            Token::BorrowedStr("borrowed"),
+
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_adjacently_tagged_enum() {
     #[derive(Debug, PartialEq, Serialize, Deserialize)]