Set all doc tests to 2018 edition

serde/src/de/ignored_any.rs

@@ -8,7 +8,7 @@ use de::{Deserialize, Deserializer, Error, MapAccess, SeqAccess, Visitor};
 /// any type, except that it does not store any information about the data that
 /// gets deserialized.
 ///
-/// ```rust
+/// ```edition2018
 /// use std::fmt;
 /// use std::marker::PhantomData;
 ///
@@ -21,7 +21,7 @@ use de::{Deserialize, Deserializer, Error, MapAccess, SeqAccess, Visitor};
 /// ///
 /// /// For example to deserialize only the element at index 3:
 /// ///
-/// /// ```rust
+/// /// ```
 /// /// NthElement::new(3).deserialize(deserializer)
 /// /// ```
 /// pub struct NthElement<T> {

serde/src/de/mod.rs

@@ -153,7 +153,7 @@ macro_rules! declare_error_trait {
             ///
             /// The message should not be capitalized and should not end with a period.
             ///
-            /// ```rust
+            /// ```edition2018
             /// # use std::str::FromStr;
             /// #
             /// # struct IpAddr;
@@ -298,7 +298,7 @@ declare_error_trait!(Error: Sized + Debug + Display);
 /// This is used as an argument to the `invalid_type`, `invalid_value`, and
 /// `invalid_length` methods of the `Error` trait to build error messages.
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::fmt;
 /// #
 /// # use serde::de::{self, Unexpected, Visitor};
@@ -423,7 +423,7 @@ impl<'a> fmt::Display for Unexpected<'a> {
 /// Within the context of a `Visitor` implementation, the `Visitor` itself
 /// (`&self`) is an implementation of this trait.
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::fmt;
 /// #
 /// # use serde::de::{self, Unexpected, Visitor};
@@ -448,7 +448,7 @@ impl<'a> fmt::Display for Unexpected<'a> {
 ///
 /// Outside of a `Visitor`, `&"..."` can be used.
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::de::{self, Unexpected};
 /// #
 /// # fn example<E>() -> Result<(), E>
@@ -569,7 +569,7 @@ pub trait Deserialize<'de>: Sized {
 /// from the input string, but a `from_reader` function may only deserialize
 /// owned data.
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::de::{Deserialize, DeserializeOwned};
 /// # use std::io::{Read, Result};
 /// #
@@ -608,7 +608,7 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 ///
 /// The canonical API for stateless deserialization looks like this:
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::Deserialize;
 /// #
 /// # enum Error {}
@@ -622,7 +622,7 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 /// Adjusting an API like this to support stateful deserialization is a matter
 /// of accepting a seed as input:
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::de::DeserializeSeed;
 /// #
 /// # enum Error {}
@@ -655,7 +655,7 @@ impl<T> DeserializeOwned for T where T: for<'de> Deserialize<'de> {}
 /// into it. This requires stateful deserialization using the `DeserializeSeed`
 /// trait.
 ///
-/// ```rust
+/// ```edition2018
 /// use std::fmt;
 /// use std::marker::PhantomData;
 ///
@@ -1145,7 +1145,7 @@ pub trait Deserializer<'de>: Sized {
     /// human-readable one and binary formats like Bincode will prefer the
     /// compact one.
     ///
-    /// ```
+    /// ```edition2018
     /// # use std::ops::Add;
     /// # use std::str::FromStr;
     /// #
@@ -1222,7 +1222,7 @@ pub trait Deserializer<'de>: Sized {
 ///
 /// # Example
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::fmt;
 /// #
 /// # use serde::de::{self, Unexpected, Visitor};
@@ -1263,7 +1263,7 @@ pub trait Visitor<'de>: Sized {
     /// "an integer between 0 and 64". The message should not be capitalized and
     /// should not end with a period.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use std::fmt;
     /// #
     /// # struct S {
@@ -2004,7 +2004,7 @@ pub trait VariantAccess<'de>: Sized {
     /// If the data contains a different type of variant, the following
     /// `invalid_type` error should be constructed:
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
     /// #
     /// # struct X;
@@ -2044,7 +2044,7 @@ pub trait VariantAccess<'de>: Sized {
     /// If the data contains a different type of variant, the following
     /// `invalid_type` error should be constructed:
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
     /// #
     /// # struct X;
@@ -2100,7 +2100,7 @@ pub trait VariantAccess<'de>: Sized {
     /// If the data contains a different type of variant, the following
     /// `invalid_type` error should be constructed:
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
     /// #
     /// # struct X;
@@ -2147,7 +2147,7 @@ pub trait VariantAccess<'de>: Sized {
     /// If the data contains a different type of variant, the following
     /// `invalid_type` error should be constructed:
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::de::{self, value, DeserializeSeed, Visitor, VariantAccess, Unexpected};
     /// #
     /// # struct X;
@@ -2207,7 +2207,7 @@ pub trait VariantAccess<'de>: Sized {
 ///
 /// # Example
 ///
-/// ```rust
+/// ```edition2018
 /// use std::str::FromStr;
 /// use serde::Deserialize;
 /// use serde::de::{value, IntoDeserializer};

serde/src/de/value.rs

@@ -1,7 +1,7 @@
 //! Building blocks for deserializing basic values using the `IntoDeserializer`
 //! trait.
 //!
-//! ```rust
+//! ```edition2018
 //! use std::str::FromStr;
 //! use serde::Deserialize;
 //! use serde::de::{value, IntoDeserializer};

serde/src/integer128.rs

@@ -9,7 +9,7 @@
 /// do not need to bother with this macro and may assume support for 128-bit
 /// integers.
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::private::ser::Error;
 /// #
 /// # struct MySerializer;
@@ -50,7 +50,7 @@
 /// When Serde is built with support for 128-bit integers, this macro expands
 /// transparently into just the input tokens.
 ///
-/// ```rust
+/// ```edition2018
 /// macro_rules! serde_if_integer128 {
 ///     ($($tt:tt)*) => {
 ///         $($tt)*
@@ -61,7 +61,7 @@
 /// When built without support for 128-bit integers, this macro expands to
 /// nothing.
 ///
-/// ```rust
+/// ```edition2018
 /// macro_rules! serde_if_integer128 {
 ///     ($($tt:tt)*) => {};
 /// }

serde/src/macros.rs

@@ -11,7 +11,7 @@
 /// input. This requires repetitive implementations of all the [`Deserializer`]
 /// trait methods.
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::forward_to_deserialize_any;
 /// # use serde::de::{value, Deserializer, Visitor};
 /// #
@@ -47,7 +47,7 @@
 /// methods so that they forward directly to [`Deserializer::deserialize_any`].
 /// You can choose which methods to forward.
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::forward_to_deserialize_any;
 /// # use serde::de::{value, Deserializer, Visitor};
 /// #
@@ -78,7 +78,7 @@
 /// called `V`. A different type parameter and a different lifetime can be
 /// specified explicitly if necessary.
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::marker::PhantomData;
 /// #
 /// # use serde::forward_to_deserialize_any;

serde/src/ser/impossible.rs

@@ -15,7 +15,7 @@ use ser::{
 /// [`SerializeTuple`], [`SerializeTupleStruct`], [`SerializeTupleVariant`],
 /// [`SerializeMap`], [`SerializeStruct`], and [`SerializeStructVariant`].
 ///
-/// ```rust
+/// ```edition2018
 /// # use serde::ser::{Serializer, Impossible};
 /// # use serde::private::ser::Error;
 /// #

serde/src/ser/mod.rs

@@ -137,7 +137,7 @@ macro_rules! declare_error_trait {
             /// For example, a filesystem [`Path`] may refuse to serialize
             /// itself if it contains invalid UTF-8 data.
             ///
-            /// ```rust
+            /// ```edition2018
             /// # struct Path;
             /// #
             /// # impl Path {
@@ -210,7 +210,7 @@ pub trait Serialize {
     /// See the [Implementing `Serialize`] section of the manual for more
     /// information about how to implement this method.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeStruct, Serializer};
     ///
     /// struct Person {
@@ -377,7 +377,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a `bool` value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -399,7 +399,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `i64` and
     /// forward to `serialize_i64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -421,7 +421,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `i64` and
     /// forward to `serialize_i64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -443,7 +443,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `i64` and
     /// forward to `serialize_i64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -461,7 +461,7 @@ pub trait Serializer: Sized {
 
     /// Serialize an `i64` value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -480,7 +480,7 @@ pub trait Serializer: Sized {
     serde_if_integer128! {
         /// Serialize an `i128` value.
         ///
-        /// ```rust
+        /// ```edition2018
         /// # use serde::Serializer;
         /// #
         /// # serde::__private_serialize!();
@@ -509,7 +509,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `u64` and
     /// forward to `serialize_u64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -531,7 +531,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `u64` and
     /// forward to `serialize_u64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -553,7 +553,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `u64` and
     /// forward to `serialize_u64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -571,7 +571,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a `u64` value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -590,7 +590,7 @@ pub trait Serializer: Sized {
     serde_if_integer128! {
         /// Serialize a `u128` value.
         ///
-        /// ```rust
+        /// ```edition2018
         /// # use serde::Serializer;
         /// #
         /// # serde::__private_serialize!();
@@ -619,7 +619,7 @@ pub trait Serializer: Sized {
     /// reasonable implementation would be to cast the value to `f64` and
     /// forward to `serialize_f64`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -637,7 +637,7 @@ pub trait Serializer: Sized {
 
     /// Serialize an `f64` value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -658,7 +658,7 @@ pub trait Serializer: Sized {
     /// If the format does not support characters, it is reasonable to serialize
     /// it as a single element `str` or a `u32`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -676,7 +676,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a `&str`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -700,7 +700,7 @@ pub trait Serializer: Sized {
     /// `serialize_seq`. If forwarded, the implementation looks usually just
     /// like this:
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::ser::{Serializer, SerializeSeq};
     /// # use serde::private::ser::Error;
     /// #
@@ -729,7 +729,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a [`None`] value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::{Serialize, Serializer};
     /// #
     /// # enum Option<T> {
@@ -762,7 +762,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a [`Some(T)`] value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::{Serialize, Serializer};
     /// #
     /// # enum Option<T> {
@@ -797,7 +797,7 @@ pub trait Serializer: Sized {
 
     /// Serialize a `()` value.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use serde::Serializer;
     /// #
     /// # serde::__private_serialize!();
@@ -817,7 +817,7 @@ pub trait Serializer: Sized {
     ///
     /// A reasonable implementation would be to forward to `serialize_unit`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     ///
     /// struct Nothing;
@@ -839,7 +839,7 @@ pub trait Serializer: Sized {
     /// this variant within the enum, and the `variant` is the name of the
     /// variant.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     ///
     /// enum E {
@@ -872,7 +872,7 @@ pub trait Serializer: Sized {
     /// wrappers around the data they contain. A reasonable implementation would
     /// be to forward to `value.serialize(self)`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     ///
     /// struct Millimeters(u8);
@@ -900,7 +900,7 @@ pub trait Serializer: Sized {
     /// this variant within the enum, and the `variant` is the name of the
     /// variant. The `value` is the data contained within this newtype variant.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     ///
     /// enum E {
@@ -938,7 +938,7 @@ pub trait Serializer: Sized {
     /// not be computable before the sequence is iterated. Some serializers only
     /// support sequences whose length is known up front.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use std::marker::PhantomData;
     /// #
     /// # struct Vec<T>(PhantomData<T>);
@@ -983,7 +983,7 @@ pub trait Serializer: Sized {
     /// This call must be followed by zero or more calls to `serialize_element`,
     /// then a call to `end`.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, Serializer, SerializeTuple};
     ///
     /// # mod fool {
@@ -1013,7 +1013,7 @@ pub trait Serializer: Sized {
     /// }
     /// ```
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeTuple, Serializer};
     ///
     /// const VRAM_SIZE: usize = 386;
@@ -1041,7 +1041,7 @@ pub trait Serializer: Sized {
     /// The `name` is the name of the tuple struct and the `len` is the number
     /// of data fields that will be serialized.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeTupleStruct, Serializer};
     ///
     /// struct Rgb(u8, u8, u8);
@@ -1073,7 +1073,7 @@ pub trait Serializer: Sized {
     /// this variant within the enum, the `variant` is the name of the variant,
     /// and the `len` is the number of data fields that will be serialized.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeTupleVariant, Serializer};
     ///
     /// enum E {
@@ -1119,7 +1119,7 @@ pub trait Serializer: Sized {
     /// be computable before the map is iterated. Some serializers only support
     /// maps whose length is known up front.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # use std::marker::PhantomData;
     /// #
     /// # struct HashMap<K, V>(PhantomData<K>, PhantomData<V>);
@@ -1167,7 +1167,7 @@ pub trait Serializer: Sized {
     /// The `name` is the name of the struct and the `len` is the number of
     /// data fields that will be serialized.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeStruct, Serializer};
     ///
     /// struct Rgb {
@@ -1203,7 +1203,7 @@ pub trait Serializer: Sized {
     /// this variant within the enum, the `variant` is the name of the variant,
     /// and the `len` is the number of data fields that will be serialized.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::ser::{Serialize, SerializeStructVariant, Serializer};
     ///
     /// enum E {
@@ -1245,7 +1245,7 @@ pub trait Serializer: Sized {
     /// using [`serialize_seq`]. Implementors should not need to override this
     /// method.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     ///
     /// struct SecretlyOneHigher {
@@ -1282,7 +1282,7 @@ pub trait Serializer: Sized {
     /// using [`serialize_map`]. Implementors should not need to override this
     /// method.
     ///
-    /// ```rust
+    /// ```edition2018
     /// use serde::{Serialize, Serializer};
     /// use std::collections::BTreeSet;
     ///
@@ -1322,7 +1322,7 @@ pub trait Serializer: Sized {
     /// delegates to [`serialize_str`]. Serializers are encouraged to provide a
     /// more efficient implementation if possible.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # struct DateTime;
     /// #
     /// # impl DateTime {
@@ -1363,7 +1363,7 @@ pub trait Serializer: Sized {
     /// of this method. If no more sensible behavior is possible, the
     /// implementation is expected to return an error.
     ///
-    /// ```rust
+    /// ```edition2018
     /// # struct DateTime;
     /// #
     /// # impl DateTime {
@@ -1398,7 +1398,7 @@ pub trait Serializer: Sized {
     /// human-readable one and binary formats like Bincode will prefer the
     /// compact one.
     ///
-    /// ```
+    /// ```edition2018
     /// # use std::fmt::{self, Display};
     /// #
     /// # struct Timestamp;
@@ -1447,7 +1447,7 @@ pub trait Serializer: Sized {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::marker::PhantomData;
 /// #
 /// # struct Vec<T>(PhantomData<T>);
@@ -1511,7 +1511,7 @@ pub trait SerializeSeq {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// use serde::ser::{Serialize, Serializer, SerializeTuple};
 ///
 /// # mod fool {
@@ -1541,7 +1541,7 @@ pub trait SerializeSeq {
 /// }
 /// ```
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::marker::PhantomData;
 /// #
 /// # struct Array<T>(PhantomData<T>);
@@ -1611,7 +1611,7 @@ pub trait SerializeTuple {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// use serde::ser::{Serialize, SerializeTupleStruct, Serializer};
 ///
 /// struct Rgb(u8, u8, u8);
@@ -1656,7 +1656,7 @@ pub trait SerializeTupleStruct {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// use serde::ser::{Serialize, SerializeTupleVariant, Serializer};
 ///
 /// enum E {
@@ -1714,7 +1714,7 @@ pub trait SerializeTupleVariant {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// # use std::marker::PhantomData;
 /// #
 /// # struct HashMap<K, V>(PhantomData<K>, PhantomData<V>);
@@ -1825,7 +1825,7 @@ pub trait SerializeMap {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// use serde::ser::{Serialize, SerializeStruct, Serializer};
 ///
 /// struct Rgb {
@@ -1885,7 +1885,7 @@ pub trait SerializeStruct {
 ///
 /// # Example use
 ///
-/// ```rust
+/// ```edition2018
 /// use serde::ser::{Serialize, SerializeStructVariant, Serializer};
 ///
 /// enum E {

serde_derive/src/lib.rs

@@ -1,6 +1,6 @@
 //! This crate provides Serde's two derive macros.
 //!
-//! ```rust
+//! ```edition2018
 //! # use serde_derive::{Serialize, Deserialize};
 //! #
 //! #[derive(Serialize, Deserialize)]

serde_test/src/token.rs

@@ -4,7 +4,7 @@ use std::fmt::{self, Debug, Display};
 pub enum Token {
     /// A serialized `bool`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&true, &[Token::Bool(true)]);
@@ -13,7 +13,7 @@ pub enum Token {
 
     /// A serialized `i8`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0i8, &[Token::I8(0)]);
@@ -22,7 +22,7 @@ pub enum Token {
 
     /// A serialized `i16`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0i16, &[Token::I16(0)]);
@@ -31,7 +31,7 @@ pub enum Token {
 
     /// A serialized `i32`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0i32, &[Token::I32(0)]);
@@ -40,7 +40,7 @@ pub enum Token {
 
     /// A serialized `i64`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0i64, &[Token::I64(0)]);
@@ -49,7 +49,7 @@ pub enum Token {
 
     /// A serialized `u8`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0u8, &[Token::U8(0)]);
@@ -58,7 +58,7 @@ pub enum Token {
 
     /// A serialized `u16`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0u16, &[Token::U16(0)]);
@@ -67,7 +67,7 @@ pub enum Token {
 
     /// A serialized `u32`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0u32, &[Token::U32(0)]);
@@ -76,7 +76,7 @@ pub enum Token {
 
     /// A serialized `u64`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0u64, &[Token::U64(0)]);
@@ -85,7 +85,7 @@ pub enum Token {
 
     /// A serialized `f32`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0f32, &[Token::F32(0.0)]);
@@ -94,7 +94,7 @@ pub enum Token {
 
     /// A serialized `f64`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&0f64, &[Token::F64(0.0)]);
@@ -103,7 +103,7 @@ pub enum Token {
 
     /// A serialized `char`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&'\n', &[Token::Char('\n')]);
@@ -112,7 +112,7 @@ pub enum Token {
 
     /// A serialized `str`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let s = String::from("transient");
@@ -122,7 +122,7 @@ pub enum Token {
 
     /// A borrowed `str`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let s: &str = "borrowed";
@@ -132,7 +132,7 @@ pub enum Token {
 
     /// A serialized `String`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let s = String::from("owned");
@@ -151,7 +151,7 @@ pub enum Token {
 
     /// A serialized `Option<T>` containing none.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let opt = None::<char>;
@@ -163,7 +163,7 @@ pub enum Token {
     ///
     /// The tokens of the value follow after this header.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let opt = Some('c');
@@ -176,7 +176,7 @@ pub enum Token {
 
     /// A serialized `()`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// assert_tokens(&(), &[Token::Unit]);
@@ -271,7 +271,7 @@ pub enum Token {
     /// After this header are the elements of the sequence, followed by
     /// `SeqEnd`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let vec = vec!['a', 'b', 'c'];
@@ -292,7 +292,7 @@ pub enum Token {
     ///
     /// After this header are the elements of the tuple, followed by `TupleEnd`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// let tuple = ('a', 100);
@@ -372,7 +372,7 @@ pub enum Token {
     ///
     /// After this header are the entries of the map, followed by `MapEnd`.
     ///
-    /// ```
+    /// ```edition2018
     /// # use serde_test::{assert_tokens, Token};
     /// #
     /// use std::collections::BTreeMap;