https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61638
dank at kegel dot com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |dank at kegel dot com --- Comment #6 from dank at kegel dot com --- g++ 5.4.0 from ubuntu 16.04 suffers from this when compiling https://bitbucket.org/chromiumembedded/cef/src/54a015f785c08083c21ec5360e154a5af6f52c57/tests/ceftests/test_util.h : In file included from tests/ceftests/download_unittest.cc:9:0: tests/ceftests/test_util.h:167:1: error: multi-line comment [-Werror=comment] // #define MY_TEST_GROUP(test_name, test_mode) \ ^ It's just a code example, nicely commented out, and the compiler falsely complains of a multiline comment.