Don't show dead code warnings for functions local to dead code

[jorgeadriano]

At the moment the following code triggers dead code warnings for both f and g. The latter is unnecessary.

fn f(){
   fn g(){};
   g();
}

rust version 0.9

[alexcrichton]

Closing as a dupe of #11380, but thanks for the bug report!

The duplicate issue raises the same concerns of warning about dead code too much because you only care about the "roots" of the dead code.

[jorgeadriano]

I did look at that one, but was not sure if it is the same issue.
Thanks for the quick reply.