[rmu09]

Aren't they talking about the c++ dialect the compiler expects without any further -std=... arguments? How does that affect the bootstrapping process? This https://gcc.gnu.org/codingconventions.html should define what C/C++ standard is acceptable in the GCC.

[cogman10]

The way I read withzombies's comment (and it could be wrong) was they were talking about the language version of the compilers source. I assumed that from the "dogfooding" portion of the comment.

[maxlybbert]

Correct, this is a discussion of which language version the compiler should follow if the programmer doesn’t specify one. It’s not about which features are acceptable when implementing the compiler.