Delphi does some simple type inference

readme.md

A quick look into the generated assembler code proves that the type is indeed resolved correctly:

Project17.dpr.26: TGeneric.GuessTheType<Exception>(x);
0041C530 8B151C484200     mov edx,[$0042481c]
0041C536 A1F4974100       mov eax,[$004197f4]
0041C53B E84CD3FFFF       call TGeneric.GuessTheType<System.SysUtils.Exception>
Project17.dpr.27: TGeneric.GuessTheType(x);
0041C540 8B151C484200     mov edx,[$0042481c]
0041C546 A1F4974100       mov eax,[$004197f4]
0041C54B E83CD3FFFF       call TGeneric.GuessTheType<System.SysUtils.Exception>
Project17.dpr.28: TGeneric.GuessTheType(s);
0041C550 8B1520484200     mov edx,[$00424820]
0041C556 A1F4974100       mov eax,[$004197f4]
0041C55B E83CD3FFFF       call TGeneric.GuessTheType<System.SysUtils.TSimpleRWSync>

Source: https://plus.google.com/+Primo%C5%BEGabrijel%C4%8Di%C4%8D/posts/edE3YWtwY3B

project17.dpr

program Project17;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  System.SysUtils;

type
  TGeneric = class
    class procedure GuessTheType<T>(const value: T);
  end;

var
  x: Exception;
  s: TSimpleRWSync;

{ TGeneric<T> }

class procedure TGeneric.GuessTheType<T>(const value: T);
begin
end;

begin
  TGeneric.GuessTheType<Exception>(x);
  TGeneric.GuessTheType(x);
  TGeneric.GuessTheType(s);
end.