http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46897
--- Comment #6 from Damian Rouson <damian at rouson dot net> 2010-12-13 15:16:42 UTC --- Janus, Thanks for finding the relevant language in the standard. In case it helps, what I submitted originally was a reduced example of code written by Jim Xia, who is member of both the IBM compiler test team and the Fortran standards committee. IBM XL Fortran 13.1 calls the defined assignment in my original example (and interestingly in Janus's reduced example, although it appears from what you wrote that it is not required to do so in your reduced example). Unfortunately, Jim is on vacation, so I probably won't be able to find out soon what part of the standard he was relying upon when he wrote the relevant code, but I know he gave it a a lot of thought becasue that code plays a central role in an algorithm that he developed with us for the open-source ForTrilinos package (http://trilinos.sandia.gov/download/trilinos-10.6.html). Every derived type in ForTrilinos extends a derived type analogous to the "parent" type in my original posting. The defined assignment is needed for a reference counting scheme to prevent memory management problems. If the compiler does not call the defined assignment, it would have significant downstream implications for all ForTrilinos derived types and for all user-defined types that aggregate or extend ForTrilinos derived types. Damian
