[clang] [clang] Add support for consteval null terminated strings (PR #173140)

[Oliver Hunt via cfe-commits]

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@@ -17726,6 +17764,10 @@ static bool EvaluateAsStringImpl(Sema &SemaRef, Expr *Message,
 
   SourceLocation Loc = Message->getBeginLoc();
   QualType T = Message->getType().getNonReferenceType();
+  if (T->isPointerType() && T->getPointeeType()->isCharType())
+    return EvaluateAsNullTerminatedCharBuffer(
+        SemaRef, Message, Result, Ctx, EvalContext, ErrorOnInvalidMessage);
+
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ojhunt wrote:

A _gross_ option would be to have a langopt + "enable this" cli flag, but that would imply people be able to rely on being able to do this.

https://github.com/llvm/llvm-project/pull/173140