This seems to have been introduced into Delphi Berlin: [WayBack] System.TypInfo.SizeOfSet – RAD Studio API Documentation. Maybe slightly earlier, but at least it was not documented in XE8 [WayBack] (via [WayBack] Delphi “SizeOfSet”.).

This is a useful function, for instance to get the Cardinality of a set in [WayBack] delphi – How can I get the number of elements of any variable of type set? – Stack Overflow.

From what I can see, the undocumented TLargestSet type also got introduced in Delphi Berlin.

Few hits by Google on [WayBack] Delphi “TLargestSet”, including [WayBack] Free Automated Malware Analysis Service – powered by Falcon Sandbox – Viewing online file analysis results for ‘Coperativa.exe’.

Not much more is documented than this in Tokyo [WayBack]:

System.TypInfo.SizeOfSet

• Up to Parent: System.TypInfo

Delphi

function SizeOfSet(TypeInfo: PTypeInfo): Integer;

C++

extern DELPHI_PACKAGE int __fastcall SizeOfSet(PTypeInfo TypeInfo);

Properties

Type	Visibility	Source	Unit	Parent
function	public	System.TypInfo.pas System.TypInfo.hpp	System.TypInfo	System.TypInfo

Description

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–jeroen