diff --git a/src/rstd/collections/pair.rs b/src/rstd/collections/pair.rs
index 9a966e7..a4afd60 100644
--- a/src/rstd/collections/pair.rs
+++ b/src/rstd/collections/pair.rs
@@ -113,3 +113,25 @@ impl<A: Serializable, B: Serializable> Serializable for (A, B) {
         StaticPairObject::<Self>::serialize_sp(self, serializer)
     }
 }
+
+impl<'a, Ctx: Context<'a>, A: MentionableBase<'a, Ctx>, B: MentionableBase<'a, Ctx>>
+    MentionableBase<'a, Ctx> for (A, B)
+{
+    type Fctr = (A::Fctr, B::Fctr);
+
+    fn factory(&self) -> Self::Fctr {
+        (self.0.factory(), self.1.factory())
+    }
+}
+
+impl<'a, Ctx: Context<'a>, FA: FactoryBase<'a, Ctx>, FB: FactoryBase<'a, Ctx>> FactoryBase<'a, Ctx>
+    for (FA, FB)
+{
+    type Mtbl = (FA::Mtbl, FB::Mtbl);
+
+    type ParseError = PairParseError<FA::ParseError, FB::ParseError>;
+}
+
+impl<A: AtomicBase, B: AtomicBase> AtomicBase for (A, B) {
+    type AParseError = PairParseError<A::AParseError, B::AParseError>;
+}