[quotemstr]

But it will propagate through a chain of unmarked check calls. If the requirement to mark potentially-throwing call sites is what disqualifies an error handling scheme as belonging to the class of exception systems, then we need a new term that includes both exceptions and this proposal and excludes everything else, because the proposed Go scheme very closely resembles exceptions.

[ecnahc515]

An unmarked check call would mean explicit error handling like if err != nil {} which isn't unchecked..it's just checked not using `check`. If you don't have this, then your error variable will be unused an you'll get a compile error.