a warning to implement

[Richard Almquist]

I would like to see this warning in -Wall.

I would also ask that you consider generating an -WallXXX that includes 
everthing in -Wall plus additional warnings that are generally usefule 
but don't meet the criteria for -Wall. This would be useful in two cases.

1) A short easy to remember option that could be used periodcally to 
catch errors by turning on a bunch of additional warnings. You can do 
this now by explicitlly adding warnings but I, at least, can never 
remember that the names without going to the documentatiuon. As a 
result, I don't tend to do this as often as I should. In this case, I 
would be willing to wade through lots of warnings about things that 
aren't problems to get warnings about the things that are.

2) I could enable this option in my Makefile and then explicitlly turn 
off the warnings that cause problems.  As new warnings are added to 
-WallXXX, I would automatically get them. If they caused problems, I 
could explicitly disable them. In this case, I would only want a few 
warnings about things that aren't problems.  I, being lazy, am much more 
likely to open up the manual to explicitly disable warnings that are 
causing me trouble than I am to open the manual to look for warnings 
that -Wall doesn't turn on but might be useful.