Parameters of type "nsIFactory" are declared in nsComponentManagerUtils.h, but nowhere are any files #included that define that type. Same for type nsIComponentManger. The problem can be fixed very simply by adding two lines near the top of the file: #include <nsIFactory.h> #include <nsIComponentManager.h> Reproducible: Always Steps to Reproduce: 1. echo "#include <nsComponentManagerUtils.h>" > foo.cpp 2. c++ -I/mozilla/dist/include foo.cpp -o foo Actual Results: /sothis/projects1/mozilla/mozilla-0.8.1-debug-enabled/dist/include/nsComponentMa nagerUtils.h:38: type specifier omitted for parameter This may be related, but I think line 26 in the same file should be changed from: #ifndef OBSOLETE_MODULE_LOADING to: #ifdef OBSOLETE_MODULE_LOADING since the code it wraps is the obsolete module loading code.

The patch posted removes those two lines, I believe. What is the problem caused by the absence of the code described above?

Bugger! I got the patch ****-backwards. Without those two headers included, nsIFactory and nsIComponentManager aren't declared anywhere. They are used in nsComponentManagerUtils.h, so they need to be declared. I only see this problem compiling non-Mozilla code. In every case where it counts, Mozilla code has obviously already included, directly or indirectly, nsIFactory.h and nsIComponentManager.h before including nsComponentManagerUtils.h. That's not the correct solution though.

I don't have an opinion on where these includes should be. But, do NOT checkin #includes that use angle brakets for non system #includes. Use double quotes. Angle brakets here would bust some platforms.

reassign all kandrot xpcom bug.

I believe this to be invalid now after my component manager change. Now, nsComponentManagerUtils.h include nsComponentManagerObsolete.h which forward declares nsIFactory. marking invalid