[just talk] what if implicitly typed literals were disallowed

[Adam D. Ruppe]

BTW, bearophile, we've talked about runtime overflow checks 
before. I'm generally against them, but if we had user defined 
basic types, we could implement them in the library (already 
possible, though some important optimization opportunities are 
missed on it right now which is a potential practical problem).

But then we could make all ints use the special overflow checked 
type too by changing a line in druntime.