Merge pull request #223 from jwilm/hinting-for-struct-keys

feat(de): Support struct key hinting

serde/src/de/mod.rs

@@ -403,6 +403,16 @@ pub trait Deserializer {
         self.visit_seq(visitor)
     }
 
+    /// This method hints that the `Deserialize` type is expecting some sort of struct key mapping.
+    /// This allows deserializers to choose between &str, usize, or &[u8] to properly deserialize a
+    /// struct key.
+    #[inline]
+    fn visit_struct_key<V>(&mut self, visitor: V) -> Result<V::Value, Self::Error>
+        where V: Visitor,
+    {
+        self.visit(visitor)
+    }
+
     /// Specify a format string for the deserializer.
     ///
     /// The deserializer format is used to determine which format

serde_codegen/src/de.rs

@@ -917,7 +917,7 @@ fn deserialize_field_visitor(
                     }
                 }
 
-                deserializer.visit(__FieldVisitor::<D>{ phantom: PhantomData })
+                deserializer.visit_struct_key(__FieldVisitor::<D>{ phantom: PhantomData })
             }
         }
     ).unwrap();