disallow (and remove) dead-code

src/derived.rs

@@ -123,8 +123,6 @@ where
             .or_insert_with(|| Arc::new(Slot::new(key.clone())))
             .clone()
     }
-
-    fn remove_lru(&self) {}
 }
 
 impl<DB, Q, MP> QueryStorageOps<DB, Q> for DerivedStorage<DB, Q, MP>

src/lib.rs

@@ -1,6 +1,5 @@
 #![warn(rust_2018_idioms)]
 #![warn(missing_docs)]
-#![allow(dead_code)]
 
 //! The salsa crate is a crate for incremental recomputation.  It
 //! permits you to define a "database" of queries with both inputs and

src/runtime.rs

@@ -159,11 +159,6 @@ where
         db.for_each_query(|query_storage| query_storage.sweep(db, strategy));
     }
 
-    /// True if `d` represents the max durability level.
-    pub(crate) fn is_constant(&self, d: Durability) -> bool {
-        d == self.max_durability()
-    }
-
     /// Returns the max durability, used for constants.
     pub(crate) fn max_durability(&self) -> Durability {
         Durability::new(self.shared_state.revisions.len() - 1)