http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55242 --- Comment #1 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> 2012-11-09 20:23:47 UTC --- It's a "feature", not a bug (see PR41748, PR45696, and PR48383). Perhaps it should be mentioned in the preprocessor documentation.