MSIR.0790 Non-readOnly property cannot be called THIS

A non-readOnly property has a Set method. In the Set method, the name of the input value is the same as the name of the property. If a non-readOnly property is called this, it means that the input value to the Set method would be referred to with the variable %this. But %this is always defined to reference the method object. This means that a non-readOnly property would produce an ambiguity in the meaning of %this inside the Set method, so it is not allowed.

Use another name for the property.