[clang] [Clang] Treat constexpr-unknown value as invalid in `evaluateValue` (PR #128409)

[Eli Friedman via cfe-commits]

================
@@ -3628,8 +3628,6 @@ static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
   if (AllowConstexprUnknown) {
     if (!Result)
       Result = &Info.CurrentCall->createConstexprUnknownAPValues(VD, Base);
-    else
-      Result->setConstexprUnknown();
----------------
efriedma-quic wrote:

Deleting this makes a lot of sense; I was really confused trying to parse what this line in the original patch was supposed to do.

https://github.com/llvm/llvm-project/pull/128409