[clang] [clang] Reject initializing constexpr struct/union types with compound literals that contain non null pointers (PR #228776)

[Abdulmalek Almkainzi via cfe-commits]

aalmkainzi wrote:

I dont use AI to write code for me. I do use it as a research tool (for example, I used it to understand how the testing syntax works).

When working with compiler projects, I've found the best way to figure out how a certain mechanism works is by making invalid code, and stepping into a debugger. So for example I make a constexpr object that has a non constant initializer, and see where that fails (`break Diag` seems to mostly work for me in clang), and from there I trace back the logic that led to the error.

https://github.com/llvm/llvm-project/pull/228776