Use BorrowedStrDeserializer instead of generated key deserializers

Cargo.toml

@@ -20,7 +20,6 @@ travis-ci = { repository = "alexcrichton/toml-rs" }
 
 [dependencies]
 serde = "1.0"
-serde_derive = "1.0"
 
 [dev-dependencies]
 serde_json = "1.0"

src/de.rs

@@ -12,6 +12,7 @@ use std::vec;
 
 use serde::de;
 use serde::de::IntoDeserializer;
+use serde::de::value::BorrowedStrDeserializer;
 
 use tokens::{Tokenizer, Token, Error as TokenError, Span};
 use datetime;
@@ -620,11 +621,11 @@ impl<'de> de::MapAccess<'de> for SpannedDeserializer<'de> {
         K: de::DeserializeSeed<'de>,
     {
         if self.start.is_some() {
-            seed.deserialize(spanned::START.into_deserializer()).map(Some)
+            seed.deserialize(BorrowedStrDeserializer::new(spanned::START)).map(Some)
         } else if self.end.is_some() {
-            seed.deserialize(spanned::END.into_deserializer()).map(Some)
+            seed.deserialize(BorrowedStrDeserializer::new(spanned::END)).map(Some)
         } else if self.value.is_some() {
-            seed.deserialize(spanned::VALUE.into_deserializer()).map(Some)
+            seed.deserialize(BorrowedStrDeserializer::new(spanned::VALUE)).map(Some)
         } else {
             Ok(None)
         }

src/lib.rs

@@ -153,8 +153,6 @@
 
 #[macro_use]
 extern crate serde;
-#[macro_use]
-extern crate serde_derive;
 
 pub mod value;
 #[doc(no_inline)]

src/spanned.rs

@@ -32,43 +32,6 @@ pub const END: &'static str = "$__toml_private_end";
 #[doc(hidden)]
 pub const VALUE: &'static str = "$__toml_private_value";
 
-macro_rules! key_deserialize {
-    ($ident:ident, $field:expr, $name:expr) => {
-        struct $ident;
-
-        impl<'de> de::Deserialize<'de> for $ident {
-            fn deserialize<D>(deserializer: D) -> Result<$ident, D::Error>
-                where D: de::Deserializer<'de>
-            {
-                struct FieldVisitor;
-
-                impl<'de> de::Visitor<'de> for FieldVisitor {
-                    type Value = ();
-
-                    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-                        formatter.write_str("a valid spanned field")
-                    }
-
-                    fn visit_str<E>(self, s: &str) -> Result<(), E>
-                        where E: de::Error
-                    {
-                        if s == $field {
-                            Ok(())
-                        } else {
-                            Err(de::Error::custom(
-                                concat!("expected spanned field `", $name, "`")))
-                        }
-                    }
-                }
-
-                deserializer.deserialize_identifier(FieldVisitor)?;
-                Ok($ident)
-            }
-        }
-    }
-}
-
-
 /// A spanned value, indicating the range at which it is defined in the source.
 #[derive(Debug)]
 pub struct Spanned<T> {
@@ -100,25 +63,19 @@ impl<'de, T> de::Deserialize<'de> for Spanned<T>
             fn visit_map<V>(self, mut visitor: V) -> Result<Spanned<T>, V::Error>
                 where V: de::MapAccess<'de>
             {
-                let start = visitor.next_key::<StartKey>()?;
-
-                if start.is_none() {
+                if visitor.next_key()? != Some(START) {
                     return Err(de::Error::custom("spanned start key not found"))
                 }
 
                 let start: usize = visitor.next_value()?;
 
-                let end = visitor.next_key::<EndKey>()?;
-
-                if end.is_none() {
+                if visitor.next_key()? != Some(END) {
                     return Err(de::Error::custom("spanned end key not found"))
                 }
 
                 let end: usize = visitor.next_value()?;
 
-                let value = visitor.next_key::<ValueKey>()?;
-
-                if value.is_none() {
+                if visitor.next_key()? != Some(VALUE) {
                     return Err(de::Error::custom("spanned value key not found"))
                 }
 
@@ -132,10 +89,6 @@ impl<'de, T> de::Deserialize<'de> for Spanned<T>
             }
         }
 
-        key_deserialize!(StartKey, START, "start");
-        key_deserialize!(EndKey, END, "end");
-        key_deserialize!(ValueKey, VALUE, "value");
-
         let visitor = SpannedVisitor(::std::marker::PhantomData);
 
         static FIELDS: [&'static str; 3] = [START, END, VALUE];