Use associated type in signature to not repeat concrete type

Author: Mingun

serde/src/de/mod.rs

@@ -1226,10 +1226,7 @@ pub trait Deserializer<'de>: Sized {
     // Not public API.
     #[cfg(all(not(no_serde_derive), any(feature = "std", feature = "alloc")))]
     #[doc(hidden)]
-    fn __deserialize_content<V>(
-        self,
-        visitor: V,
-    ) -> Result<crate::__private::de::Content<'de>, Self::Error>
+    fn __deserialize_content<V>(self, visitor: V) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de, Value = crate::__private::de::Content<'de>>,
     {

serde/src/private/de.rs

@@ -1497,7 +1497,7 @@ mod content {
             visitor.visit_unit()
         }
 
-        fn __deserialize_content<V>(self, visitor: V) -> Result<Content<'de>, Self::Error>
+        fn __deserialize_content<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where
             V: Visitor<'de, Value = Content<'de>>,
         {
@@ -2086,7 +2086,7 @@ mod content {
             visitor.visit_unit()
         }
 
-        fn __deserialize_content<V>(self, visitor: V) -> Result<Content<'de>, Self::Error>
+        fn __deserialize_content<V>(self, visitor: V) -> Result<V::Value, Self::Error>
         where
             V: Visitor<'de, Value = Content<'de>>,
         {