code: private Map<MethodSymbol, Attribute> getAllValues() {
          Map<MethodSymbol, Attribute> res = new LinkedHashMap<>();
  
          // First find the default values.
          ClassSymbol sym = (ClassSymbol) anno.type.tsym;
          for (Symbol s : sym.members().getSymbols(NON_RECURSIVE)) {
              if (s.kind == MTH) {
                  MethodSymbol m = (MethodSymbol) s;
                  Attribute def = m.getDefaultValue();
                  if (def != null)
                      res.put(m, def);
              }
          }
          // Next find the explicit values, possibly overriding defaults.
          for (Pair<MethodSymbol, Attribute> p : anno.values)
              res.put(p.fst, p.snd);
          return res;
      }
docs: Returns a map from element symbols to their values.
  Includes all elements, whether explicit or defaulted.