code: private void mapSerialFieldTagImplsToFieldDocImpls(FieldDocImpl spfDoc,
                                                         DocEnv env,
                                                         ClassSymbol def) {
          Names names = def.name.table.names;
          for (SerialFieldTag tag : spfDoc.serialFieldTags()) {
              if (tag.fieldName() == null || tag.fieldType() == null) // ignore malformed @serialField tags
                  continue;
  
              Name fieldName = names.fromString(tag.fieldName());
  
              // Look for a FieldDocImpl that is documented by serialFieldTagImpl.
              for (Symbol sym : def.members().getSymbolsByName(fieldName)) {
                  if (sym.kind == VAR) {
                      VarSymbol f = (VarSymbol) sym;
                      FieldDocImpl fdi = env.getFieldDoc(f);
                      ((SerialFieldTagImpl) (tag)).mapToFieldDocImpl(fdi);
                      break;
                  }
              }
          }
      }
docs: /*
  Associate serialField tag fieldName with FieldDocImpl member.
  Note: A serialField tag does not have to map an existing field
  of a class.