Some examples of the "E2015: Operator not applicable to this operand type" when using generics

E2015WithGenerics.dpr

program E2015WithGenerics;

uses
  System.SysUtils;

{$APPTYPE CONSOLE}

{$R *.res}

type
  TMyAncestor = class
  end;

  TMyClass = class(TMyAncestor)
  strict protected
    function GetClassInstance<T: class>: T;
    function GetTMyAncestorInstance<T: TMyAncestor>: T;
//    function GetTMyClassInstance<T: TMyClass>: T; // [dcc32 Error] E2086 Type 'TMyClass' is not yet completely defined
  end;

function TMyClass.GetClassInstance<T>: T;
var
  lClassType: TClass;
begin
  lClassType := T;
  if lClassType = TMyClass then
  begin
    Result := T(Self)
  end
  else if T = TMyClass then
  begin
    Result := T(Self)
  end
//  else if lClassType is TMyClass then // [dcc32 Error] E2015 Operator not applicable to this operand type
//  begin
//    Result := T(Self)
//  end
//  else if T is TMyClass then // [dcc32 Error] E2015 Operator not applicable to this operand type
//  begin
//    Result := T(Self)
//  end
  else if lClassType.InheritsFrom(TMyClass) then
  begin
    Result := T(Self)
  end
  else if T.InheritsFrom(TMyClass) then
  begin
    Result := T(Self)
  end
  else
  begin
    raise ENotSupportedException.CreateFmt('GetClassInstance fails for class %s', [lClassType.ClassName]);
  end;
end;

function TMyClass.GetTMyAncestorInstance<T>: T;
var
  lClassType: TClass;
begin
  lClassType := T;
  if lClassType = TMyClass then
  begin
    Result := T(Self)
  end
//  else if T = TMyClass then // [dcc32 Error] E2015 Operator not applicable to this operand type
//  begin
//    Result := T(Self)
//  end
//  else if lClassType is TMyClass then // [dcc32 Error] E2015 Operator not applicable to this operand type
//  begin
//    Result := T(Self)
//  end
//  else if T is TMyClass then // [dcc32 Error] E2015 Operator not applicable to this operand type
//  begin
//    Result := T(Self)
//  end
  else if lClassType.InheritsFrom(TMyClass) then
  begin
    Result := T(Self)
  end
  else if T.InheritsFrom(TMyClass) then
  begin
    Result := T(Self)
  end
  else
  begin
    raise ENotSupportedException.CreateFmt('GetTMyAncestorInstance fails for class %s', [lClassType.ClassName]);
  end;
end;

//function TMyClass.GetTMyClassInstance<T>: T;
//begin
////...
//end;

begin
end.