Upgrade to Rust 2018

Since ordered-float v2 bumps the MSRV to 1.34, might as well take the
opportunity to upgrade to Rust 2018 syntax.

Cargo.toml

@@ -2,6 +2,7 @@
 name = "serde-value"
 version = "0.6.0"
 authors = ["arcnmx"]
+edition = "2018"
 
 description = "Serialization value trees"
 documentation = "http://arcnmx.github.io/serde-value/serde_value/"

src/de.rs

@@ -1,10 +1,10 @@
-use serde::de;
+use serde::{forward_to_deserialize_any, de};
 use std::collections::BTreeMap;
 use std::error::Error;
 use std::fmt;
 use std::marker::PhantomData;
 
-use Value;
+use crate::Value;
 
 #[derive(Debug)]
 pub enum Unexpected {
@@ -96,15 +96,15 @@ impl de::Error for DeserializerError {
         DeserializerError::Custom(msg.to_string())
     }
 
-    fn invalid_type(unexp: de::Unexpected, exp: &de::Expected) -> Self {
+    fn invalid_type(unexp: de::Unexpected, exp: &dyn de::Expected) -> Self {
         DeserializerError::InvalidType(unexp.into(), exp.to_string())
     }
 
-    fn invalid_value(unexp: de::Unexpected, exp: &de::Expected) -> Self {
+    fn invalid_value(unexp: de::Unexpected, exp: &dyn de::Expected) -> Self {
         DeserializerError::InvalidValue(unexp.into(), exp.to_string())
     }
 
-    fn invalid_length(len: usize, exp: &de::Expected) -> Self {
+    fn invalid_length(len: usize, exp: &dyn de::Expected) -> Self {
         DeserializerError::InvalidLength(len, exp.to_string())
     }
 
@@ -268,15 +268,15 @@ impl<'de> de::Visitor<'de> for ValueVisitor {
 
     fn visit_seq<V: de::SeqAccess<'de>>(self, mut visitor: V) -> Result<Value, V::Error> {
         let mut values = Vec::new();
-        while let Some(elem) = try!(visitor.next_element()) {
+        while let Some(elem) = visitor.next_element()? {
             values.push(elem);
         }
         Ok(Value::Seq(values))
     }
 
     fn visit_map<V: de::MapAccess<'de>>(self, mut visitor: V) -> Result<Value, V::Error> {
         let mut values = BTreeMap::new();
-        while let Some((key, value)) = try!(visitor.next_entry()) {
+        while let Some((key, value)) = visitor.next_entry()? {
             values.insert(key, value);
         }
         Ok(Value::Map(values))

src/lib.rs

@@ -1,13 +1,5 @@
 #![doc(html_root_url="https://arcnmx.github.io/serde-value")]
 
-#[macro_use]
-extern crate serde;
-extern crate ordered_float;
-
-#[cfg(test)]
-#[macro_use]
-extern crate serde_derive;
-
 use std::collections::BTreeMap;
 use std::cmp::Ordering;
 use std::hash::{Hash, Hasher};

src/ser.rs

@@ -3,7 +3,7 @@ use std::collections::BTreeMap;
 use std::error::Error;
 use std::fmt;
 
-use Value;
+use crate::Value;
 
 #[derive(Debug)]
 pub enum SerializerError {