------- Comment #24 from paolo dot carlini at oracle dot com 2009-03-14 12:06 ------- I agree with your analysis. Can you please open a separate PR about __is_abstract (which would be a C++ report): currently, we are trying to complete the types, but we do not error out in case of incompleteness. Apparently, according to your testcase, in order to obtain a consistent behaviour we should require completeness (unless array or void), for __is_abstract and all the other builtins for which it is a precondition.
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39405