diff --git a/src/memory.hh b/src/memory.hh
index 26b506a6..7aaff5fe 100644
--- a/src/memory.hh
+++ b/src/memory.hh
@@ -30,6 +30,7 @@ enum class MemoryDomain
     Registers,
     Client,
     WordDB,
+    Selections,
     Count
 };
 
@@ -54,6 +55,7 @@ inline const char* domain_name(MemoryDomain domain)
         case MemoryDomain::Values: return "Values";
         case MemoryDomain::Registers: return "Registers";
         case MemoryDomain::Client: return "Client";
+        case MemoryDomain::Selections: return "Selections";
         case MemoryDomain::Count: break;
     }
     kak_assert(false);
@@ -118,6 +120,15 @@ bool operator!=(const Allocator<T1, d1>& lhs, const Allocator<T2, d2>& rhs)
     return d1 != d2;
 }
 
+template<typename T>
+struct TypeDomain
+{
+    static constexpr MemoryDomain domain = TypeDomain::helper((T*)nullptr);
+private:
+    template<typename U> static decltype(U::Domain) constexpr helper(U*) { return U::Domain; }
+    static constexpr MemoryDomain helper(...) { return MemoryDomain::Undefined; }
+};
+
 }
 
 #endif // memory_hh_INCLUDED
diff --git a/src/selection.hh b/src/selection.hh
index 8370df1f..cc435aed 100644
--- a/src/selection.hh
+++ b/src/selection.hh
@@ -11,6 +11,8 @@ using CaptureList = Vector<String>;
 // A selection is a Selection, associated with a CaptureList
 struct Selection
 {
+    static constexpr MemoryDomain Domain = MemoryDomain::Selections;
+
     Selection() = default;
     Selection(ByteCoord pos) : Selection(pos,pos) {}
     Selection(ByteCoord anchor, ByteCoord cursor,
@@ -68,6 +70,8 @@ enum class InsertMode : unsigned
 
 struct SelectionList
 {
+    static constexpr MemoryDomain Domain = MemoryDomain::Selections;
+
     SelectionList(Buffer& buffer, Selection s);
     SelectionList(Buffer& buffer, Selection s, size_t timestamp);
     SelectionList(Buffer& buffer, Vector<Selection> s);
diff --git a/src/unordered_map.hh b/src/unordered_map.hh
index b114df69..2c54a0da 100644
--- a/src/unordered_map.hh
+++ b/src/unordered_map.hh
@@ -9,7 +9,7 @@
 namespace Kakoune
 {
 
-template<typename Key, typename Value, MemoryDomain domain = MemoryDomain::Undefined>
+template<typename Key, typename Value, MemoryDomain domain = TypeDomain<Key>::domain>
 using UnorderedMap = std::unordered_map<Key, Value, Hash<Key>, std::equal_to<Key>,
                                         Allocator<std::pair<const Key, Value>, domain>>;
 
diff --git a/src/vector.hh b/src/vector.hh
index 987b80f9..db137b24 100644
--- a/src/vector.hh
+++ b/src/vector.hh
@@ -8,7 +8,7 @@
 namespace Kakoune
 {
 
-template<typename T, MemoryDomain domain = MemoryDomain::Undefined>
+template<typename T, MemoryDomain domain = TypeDomain<T>::domain>
 using Vector = std::vector<T, Allocator<T, domain>>;
 
 }