Is there a pragma or command line option to ask DMD to show a warning when it implicitly casts from long to ulong ?

[Ecstatic Coder via Digitalmars-d-learn]

It's taken me some time to find an implicit cast bug ("if 
(my_sometimes_negative_index >= this_array.length)"), while a 
simple C++-like implicit-cast warning would have allowed me to 
find this nasty bug WAY sooner...