Question about RunTime Errors

[wwells]

1. In the function library I see this in the description of "+" and some other functions: Details:

   Float and double overflows do not produce runtime errors but result in positive or negative infinity, which would be carried through any subsequent calculations (see IEEE 754). Use impute.ensureFinite to produce errors from infinite or NaN values.

Runtime Errors:

#18000: Integer results above or below -2147483648 and 2147483647 (inclusive) produce an "int overflow" runtime error.
#18001: Long-integer results above or below -9223372036854775808 and 9223372036854775807 (inclusive) produce a "long overflow" runtime error.

So first it says that there are no runtime errors for overflow, then it says that there are. It would be good to decide on one of those. Or maybe there are only if impute.ensureFinite is used? How can one use it?