code: public void inc(String name, int con) throws IOException
      {
          if (hasLocalVariable(name))
          {
              tinc(name, con);
          }
          else
          {
              VariableElement field = El.getField(subClass, name);
              if (field == null)
              {
                  throw new IllegalArgumentException("field "+name+" not found");
              }
              aload(0);
              getField(field);
              TypeMirror type = field.asType();
              tconst(type, con);
              tadd(type);
              aload(0);
              swap();
              putField(field);
          }
      }
docs: Increment local variable or field by constant
  <p>Stack: No change
  @param name local variable name
  @param con signed byte
  @throws IOException
  @see nameArgument
  @see addVariable