I ran into a problem while trying to add some basic elements today.
I included rust as a new element and tried to code the interaction between metal and saltwater.

else if(t==PT_SLTW)
[...]
else if(((r&0xFF)==PT_METL && 1>(rand()%7000)) || ((r&0xFF)==PT_BRMT && 1>(rand()%700)))
{
parts[r>>8].type = PT_RUST;
}

It works fine with any element I use, broken metal, breakable metal, NSCN, wood, etc...

But it will not corrode PT_METL, whatever I do.

Also going the other way round, (if (t==PT_METL)(do something)) doesn't react in any way.

Where is my error?

Thanks alot!
That'll help