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

[Mariya Podchishchaeva via cfe-commits]

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@@ -8569,6 +8571,37 @@ static bool checkForConflictWithNonVisibleExternC(Sema &S, const T *ND,
   return false;
 }
 
+static bool CheckC23ConstexprVarType(Sema &SemaRef, SourceLocation VarLoc,
+                                     QualType T) {
+
+  if (T->isVariableArrayType()) {
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Fznamznon wrote:

Uses `isVariablyModifiedType()`.

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