https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92114
--- Comment #3 from urbanjost at comcast dot net --- I could not get the code to compile at all with 7.4.0 trying a variety of compiler switches with 7.4.0. This was in a Cygwin environment. I reinstalled the Cygwin environment and still got the error. 7.4.0-1 is the highest standard version on the Cygwin site; but 8.3.0 was available as a test version. The problem went away with 8.3.0.