diff --git a/rtl/inc/system.fpd b/rtl/inc/system.fpd
index 738f47163f..3fcc54b46f 100644
--- a/rtl/inc/system.fpd
+++ b/rtl/inc/system.fpd
@@ -96,6 +96,7 @@ Function GetTypeKind(Const T : AnyType) : TTypeKind;
 Procedure Fail;
 Function TypeOf(T : TObjectType) : Pointer;
 Function IsManagedType(T : TType) : Boolean;
+Function IsConstValue(V : TAnyType) : Boolean;
 Procedure Initialize(Var T : TAnyType; ACount : SizeInt = 1);
 Procedure Finalize(Var T : TAnyType; ACount : SizeInt = 1);