Why is this an issue?

Casting an object only to free it is superfluous. TObject.Free will always call the correct destructor, regardless of the variable's type.

Also, because the Free method is on TObject, it is present on all objects inheriting from TObject - no casting is needed to access it.

Exceptions

This rule excludes cases in which the object being cast is untyped, as an untyped variable would need to be cast to be used with FreeAndNil or TObject.Free.

Noncompliant Code Example

TMyObject(MyVar).Free; // Noncompliant
(MyVar as TMyObject).Free; // Noncompliant
FreeAndNil(TMyObject(MyVar)); // Noncompliant
FreeAndNil(MyVar as TMyObject); // Noncompliant

MyVar.Free; // Compliant
FreeAndNil(MyVar); // Compliant

How to fix it

Remove the unnecessary cast:

TMyObject(MyVar).Free;
FreeAndNil(TMyObject(MyVar));

MyVar.Free;
FreeAndNil(MyVar);