Ok, got some answers. It seems GCC leads by adding non-standard features, and ICC/Clang follow to be compatible. This doesn’t seem to be the case in the JS world, where the competitors seem to be on a more equal footing (though V8 has the mindshare lead, with node.js etc.). If this is enough to support the “first ever” description is I guess a matter of personal taste at this point. All in all, thanks for the counter Gwern.
Ok, got some answers. It seems GCC leads by adding non-standard features, and ICC/Clang follow to be compatible. This doesn’t seem to be the case in the JS world, where the competitors seem to be on a more equal footing (though V8 has the mindshare lead, with node.js etc.). If this is enough to support the “first ever” description is I guess a matter of personal taste at this point. All in all, thanks for the counter Gwern.