[clang] [C23] Implement N3018: The constexpr specifier for object definitions (PR #73099)

[Timm Baeder via cfe-commits]

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@@ -4110,6 +4117,10 @@ static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
     }
 
     bool IsConstant = BaseType.isConstant(Info.Ctx);
+    bool ConstexprVar = false;
+    if (const auto *VD = dyn_cast_or_null<VarDecl>(
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tbaederr wrote:

```suggestion
    if (const auto *VD = dyn_cast_if_present<VarDecl>(
```

https://github.com/llvm/llvm-project/pull/73099