diff --git a/uppsrc/Core/Map.h b/uppsrc/Core/Map.h
index 804d07638..646938376 100644
--- a/uppsrc/Core/Map.h
+++ b/uppsrc/Core/Map.h
@@ -235,7 +235,8 @@ public:
 	VectorMap()                                                       {}
 	VectorMap(std::initializer_list<std::pair<K, T>> init) : B::AMap(init) {}
 
-	VectorMap& operator()(const K& k, const T& v)        { B::Add(k, v); return *this; }
+	template <class KK, class TT>
+	VectorMap& operator()(KK&& k, TT&& v)                { B::Add(std::forward<KK>(k), std::forward<TT>(v)); return *this; }
 
 	friend void    Swap(VectorMap& a, VectorMap& b)      { a.B::Swap(b); }
 
@@ -279,7 +280,8 @@ public:
 
 	ArrayMap(std::initializer_list<std::pair<K, T>> init) : B::AMap(init) {}
 
-	ArrayMap& operator()(const K& k, const T& v)         { Add(k, v); return *this; }
+	template <class KK, class TT>
+	ArrayMap& operator()(KK&& k, TT&& v)           { Add(std::forward<KK>(k), std::forward<TT>(v)); return *this; }
 
 	friend void    Swap(ArrayMap& a, ArrayMap& b)        { a.B::Swap(b); }
 
diff --git a/uppsrc/Core/src.tpp/ArrayMap_en-us.tpp b/uppsrc/Core/src.tpp/ArrayMap_en-us.tpp
index 2b0ac23ea..1f86a844c 100644
--- a/uppsrc/Core/src.tpp/ArrayMap_en-us.tpp
+++ b/uppsrc/Core/src.tpp/ArrayMap_en-us.tpp
@@ -61,11 +61,12 @@ d`::pair]<[*@4 K], [*@4 T]>>_[*@3 init])&]
 [s2; C`+`+ 11 initialization.&]
 [s3; &]
 [s4;%- &]
-[s5;:Upp`:`:ArrayMap`:`:operator`(`)`(const K`&`,const T`&`):%- [*_^Upp`:`:ArrayMap^ Ar
-rayMap][@(0.0.255) `&]_[* operator()]([@(0.0.255) const]_[*@4 K][@(0.0.255) `&]_[*@3 k], 
-[@(0.0.255) const]_[*@4 T][@(0.0.255) `&]_[*@3 v])&]
+[s5;:Upp`:`:ArrayMap`:`:operator`(`)`(KK`&`&`,TT`&`&`):%- [@(0.0.255) template]_<[@(0.0.255) c
+lass]_[*@4 KK], [@(0.0.255) class]_[*@4 TT]>_[*_^Upp`:`:ArrayMap^ ArrayMap][@(0.0.255) `&]_
+[* operator()]([*@4 KK][@(0.0.255) `&`&]_[*@3 k], [*@4 TT][@(0.0.255) `&`&]_[*@3 v])&]
 [s2; Same as Add([%-*@3 k], [%-*@3 v]), returns `*this. Syntax sugar 
-for creating map.&]
+for creating map. Note the use of universal reference that gets 
+resolved to correct Add variant.&]
 [s3; &]
 [s4;%- &]
 [s5;:ArrayMap`:`:ArrayMap`(const ArrayMap`&`,int`):%- [* ArrayMap]([@(0.0.255) const]_[* Ar
diff --git a/uppsrc/Core/src.tpp/VectorMap_en-us.tpp b/uppsrc/Core/src.tpp/VectorMap_en-us.tpp
index 96a38c255..89a6eb687 100644
--- a/uppsrc/Core/src.tpp/VectorMap_en-us.tpp
+++ b/uppsrc/Core/src.tpp/VectorMap_en-us.tpp
@@ -62,11 +62,12 @@ td`::pair]<[*@4 K], [*@4 T]>>_[*@3 init])&]
 [s2; C`+`+ 11 initialization.&]
 [s3; &]
 [s4;%- &]
-[s5;:Upp`:`:VectorMap`:`:operator`(`)`(const K`&`,const T`&`):%- [*_^Upp`:`:VectorMap^ V
-ectorMap][@(0.0.255) `&]_[* operator()]([@(0.0.255) const]_[*@4 K][@(0.0.255) `&]_[*@3 k], 
-[@(0.0.255) const]_[*@4 T][@(0.0.255) `&]_[*@3 v])&]
+[s5;:Upp`:`:VectorMap`:`:operator`(`)`(KK`&`&`,TT`&`&`):%- [@(0.0.255) template]_<[@(0.0.255) c
+lass]_[*@4 KK], [@(0.0.255) class]_[*@4 TT]>_[_^Upp`:`:VectorMap^ VectorMap][@(0.0.255) `&]_
+[* operator()]([*@4 KK][@(0.0.255) `&`&]_[*@3 k], [*@4 TT][@(0.0.255) `&`&]_[*@3 v])&]
 [s2; Same as Add([%-*@3 k], [%-*@3 v]), returns `*this. Syntax sugar 
-for creating map.&]
+for creating map. Note the use of universal reference that gets 
+resolved to correct Add variant.&]
 [s3; &]
 [s4;%- &]
 [s5;:VectorMap`:`:VectorMap`(const VectorMap`&`,int`):%- [* VectorMap]([@(0.0.255) const]_