[Bug c/80529] Split "C++ style comments are not allowed in ISO C90" pedwarn into its own warning flag

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80529

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |msebor at gcc dot gnu.org

--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> ---
I also don't think that adding a pure style warning for // comments is in line
with GCC philosophy.  Quoting from the GCC manual:

  Warnings are diagnostic messages that report constructions that are not
  inherently erroneous but that are risky or suggest there may have been
  an error. 

Unlike with the traditional C-style comments, I don't know of any problems due
to C++-style comments, so I don't think adding a warning option for them would
be appropriate.

Regarding the exceptions cited in comment #2, I believe those exist not so much
to help enforce particular coding styles but rather to avoid relying on C++
features that, at the time they were made available in G++, either weren't
universally supported or weren't implemented efficiently enough to be suitable
for all projects (e.g., embedded code would avoid some of these C++ features to
minimize code bloat).