convertOrElse

Defaulted target, Auto (ladder rows 2/4/6/8): absent → fallback silent; sanctioned null → fallback silent; broken → fallback + MappingDegradation.AbsorbedConversionError whose cause is the TYPED exception from toMappingException. Only Exceptions are absorbed: CancellationException and Errors always propagate.

Nullable-default variant of convertOrElse, Auto: identical ladder, but the fallback is the target field's OWN default, which is statically nullable (val x: T? = …), so the landing type is T?. The copy stage reaches this overload whenever a nullable target field also carries a constructor default — base.x is then typed T?, which the non-null fallback: T overload cannot accept (issue #20). A null default and the type's null absence form coincide here, so source-null/sanctioned-null/broken all land on fallback (null in the common case), while a non-null declared default is still honoured (the ladder's "declared default" rung). Only Exceptions are absorbed: CancellationException and Errors always propagate.