how to write expression in such case-16 (mask path following shape path)

Hi,

I dnt understand something. I want a mask path (I masked a text) to follow a shape layer's path. so That I dnt need to create multiple keyframes. but the text mask path changes its position the moment I whip it with the rectangle's path keyframes. I want the animation to be same, red rectangle will reveal and simultaneously the text mask will reveal another text beneath (white text,) . so long I created keyframes for two layers. one rectangle path and the mask path. Then Suddenly I think why dnt I use expression. I can use expression to link one's path with another. right? But as usual I failed. 😣

please help me. please 😥

no way I can insert gif or any images. weird