conversion warnings in c++

[Eric Christopher]

So, for calls in c++ we're warning unconditionally on something like:
int bar (int a, int b);

int main (void)
{
  float foo = 5.0;
  float baz = 10.0;

  bar (foo, baz);

  return 0;
}

int bar (int a, int b)
{
  return a + b;
}

whereas in C we're warning depending on Wtraditional or Wconversion.  
As far as I can tell there's no required diagnostic for this in C++,  
though I could have missed it.

So, either a) did I miss something? or b) any objections to  
conditionalizing the warnings on Wconversion (or some method of  
turning them off)?

-eric