One of my peeves about C++ is when I accidentally define a variable a
second time within the same function, usually from copying some code
around and then forgetting it. I've been running into this more now that I
am using C++'s ability to declare vars anywhere in a function instead of
all at the start.

For example:

void func(void)
{
  int x;

  {
      int x;
  }
}

I realize that this is legal in C, and therefore C++ allows it as well.
While people can argue about whether it is good practice or not, it
probably has to remain a feature of the language for backward
compatibility.

My question is whether it would be possible for the standard to specify
that a C++ compiler should provide an option to warn the user if this is
encountered. Is there a precedent for specifying compiler warnings as part
of the standard? Is this a good idea or is it a way for vendors to
differentiate their offerings?

Thanks,
Alex

--
Alex L. Bangs
bangs@netcom.com
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