The only built-in implicit conversions in C# are for numerics, and there isn't a loss in precision for those (with the exception of int/uint/long/ulong -> float and long/ulong -> double, where there is a loss of precision).

http://msdn.microsoft.com/en-us/library/y5b434w4.aspx

     int i = "5"; 

would not work.

Not the kind you seem to be thinking of.