[llvm] [llvm] Support building with c++23 (PR #154372)

[A. Jiang via llvm-commits]

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@@ -615,7 +623,7 @@ bool SwitchMatcher::addMatcher(Matcher &Candidate) {
 }
 
 void SwitchMatcher::finalize() {
-  assert(Condition == nullptr && "Already finalized");
+  assert(Condition.get() == nullptr && "Already finalized");
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frederick-vs-ja wrote:

If the `Condition` is uninitialized (not in its lifetime), calling `get` is also undefined, see [[basic.life]/8.2](https://eel.is/c++draft/basic.life#8.2).

If `Condition` is not yet constructed or already destroyed here, I think this is bug that should be fixed in another PR.

https://github.com/llvm/llvm-project/pull/154372