docs: public static Matcher<? super MethodInvocationTree> sameArgument(
        final int index1, final int index2) {
      return new Matcher<MethodInvocationTree>() {
        @Override
        public boolean matches(MethodInvocationTree methodInvocationTree, VisitorState state) {
          List<? extends ExpressionTree> args = methodInvocationTree.getArguments();
          return ASTHelpers.sameVariable(args.get(index1), args.get(index2));
        }
      };
    }