[clang] [clang-tools-extra] [clangd] [AST] Handle uninitialized type constraints (PR #110496)

[Florian Albrechtskirchinger via cfe-commits]

falbrechtskirchinger wrote:

> We need to resort to `-fallow-pch-with-compiler-errors` :)

Ah, thanks! I would not have figured that out on my own. :)

> Specifically, add the following file to `clang/test/PCH` (or somehow merge it into a pre-existing test, which I'd prefer)

I looked through that directory and found only one test with `-fallow-pch-with-compiler-errors` and `-std=c++20`: `race-condition.cpp` – not a great fit.

`cxx2a-constraints-crash.cpp` sounds promising and doesn't need too much modification. I'm including this in my next push, but I have an annotated standalone file based on your suggestion ready to go if needed.


https://github.com/llvm/llvm-project/pull/110496