[clang] [clang]: support std::meta::info for primitive types (PR #190356)

[Eli Friedman via cfe-commits]

================
@@ -1,6 +1,10 @@
 // RUN: %clang_cc1 -std=c++26 -freflection -triple x86_64-unknown-linux-gnu \
 // RUN:   -emit-llvm -o - %s -verify
 
+constexpr auto r = ^^int;
+constexpr auto q = r;
----------------
efriedma-quic wrote:

Example testcase for mangling:

```
template<typename T> auto f() -> decltype((T)^^int,1) {return 1;}
void g() { f<std::meta::info>(); }
```

https://github.com/llvm/llvm-project/pull/190356