http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50312
Meador Inge <meadori at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |meadori at gmail dot com --- Comment #1 from Meador Inge <meadori at gmail dot com> 2011-09-08 02:12:40 UTC --- This looks fixed in the HEAD revision (GCC 4.7): [meadori@motherbrain gcc]$ ../../install/bin/i686-pc-linux-gnu-gcc -v Using built-in specs. COLLECT_GCC=../../install/bin/i686-pc-linux-gnu-gcc COLLECT_LTO_WRAPPER=/home/meadori/code/gnu/install/libexec/gcc/i686-pc-linux-gnu/4.7.0/lto-wrapper Target: i686-pc-linux-gnu Configured with: ../../src/gcc/configure --host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --target=i686-pc-linux-gnu --prefix=/home/meadori/code/gnu/install/ --enable-languages=c,c++ Thread model: posix gcc version 4.7.0 20110903 (experimental) (GCC) [meadori@motherbrain gcc]$ cat test.cpp #include <cstddef> #ifdef BUG template <typename T=int> #define EXTRA <> #else #define EXTRA #endif struct foo { int bar; enum { END = offsetof(foo, bar) }; }; foo EXTRA a; [meadori@motherbrain gcc]$ ../../install/bin/i686-pc-linux-gnu-gcc -DBUG test.cpp test.cpp: In instantiation of ‘struct foo<>’: test.cpp:12:11: required from here test.cpp:10:9: error: invalid use of incomplete type ‘struct foo<>’ test.cpp:8:8: error: declaration of ‘struct foo<>’