Nope. I actually read a whole paper by a law professor about the topic. The subject of the parent post I replied to was "One constitutional amendment", not "a law".
Would my head (metaphorically) explode if an amendment was ruled unconstitutional? Absolutely.
Since you mention it, would my head (metaphorically) explode if a law that was SPECIFICALLY AUTHORIZED BY THE CONSTITUTION was ruled unconstitutional? Just as absolutely. I'm not sure what would happen if something so clearly illegal was done, though. Interesting times, for sure.