Hi all, I'm working on some code which if naively implemented would involve deep template nesting. Since I can't get a version using MPL algorithms to work on BCC 5.5.1 or VC6 , I wrote out the algorithm with hand-coded loop unrolling. It worked beautifully on a whole bunch of compilers, but when I tried it on GCC 2.95 I found I had to set the template nesting depth to 34 to get it to compile. The same code worked on GCC 3.2 with the depth restricted to 11. After making a few changes, I got the depth on GCC 2.95 (and 3.2) down to 7. One of the changes I made was to switch from using is_based_and_derived to a hand-rolled version restricted to a particular base type. This last change eliminated 11 levels of nesting on GCC 2.95 and 4 on GCC 3.2, although is_based_and_derived had been used in only one place, with fairly simple types, at the center of the algorithm. So I am wondering: is GCC 2.9x known to to be wasteful with respect to template nesting? Also, are the workarounds for GCC 2.9x in Type Traits or MPL known to add a lot of extra template nesting? Jonathan