code: @Override
      public void visitCode(final Code obj) {
          try {
              if (methodSignatureIsConstrained) {
                  return;
              }
  
              if (obj.getCode() == null) {
                  return;
              }
              Method m = getMethod();
  
              if (m.isSynthetic()) {
                  return;
              }
  
              if (m.getName().startsWith("access$")) {
                  return;
              }
  
              methodIsStatic = m.isStatic();
              parmCount = m.getArgumentTypes().length;
  
              if (parmCount == 0) {
                  return;
              }
  
              parameterDefiners.clear();
              usedParameters.clear();
              stack.resetForMethodEntry(this);
  
              if (buildParameterDefiners()) {
                  try {
                      super.visitCode(obj);
                      reportBugs();
                  } catch (StopOpcodeParsingException e) {
                      // no more possible parameter definers
                  }
              }
          } catch (ClassNotFoundException cnfe) {
              bugReporter.reportMissingClass(cnfe);
          }
      }
docs: implements the visitor to collect information about the parameters of a this
  method
  
  @param obj the currently parsed code block