Recursive DDIC structures

Hi everyone,

today I ran into a rather odd problem when defining my DDIC types.

What I want to do is rather simple: I want to read information about a folder that can have subfolders which can then again have subfolders and so on. Just like in the Windows file explorer.

Now my approach was rather straight forward:

1. Create a structure with some basic data.
2. Create a table type of that structure.
3. Now I went back to the structure from 1 and added another attribute named "subfolders" with the TYPE of 2.

Activation works well, no errors or warnings.

When I try to use this structure in my ABAP program it does not compile with the error "There is already a type called "My TableType Name".

Of course when I remove the attribute that I added in 3 everything works fine.

Anyone any ideas? Why does the structure activate? What is the best practice to do recursive structures in DDIC?

cheers Carsten