[compiler-rt] [Sema] add cast from IncompleteArrayType to ConstantArrayType in TryReferenceListInitialization (PR #65918)

[Mariya Podchishchaeva via llvm-commits]

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@@ -4532,6 +4532,15 @@ static void TryReferenceListInitialization(Sema &S,
       if (T1Quals.hasAddressSpace())
         Sequence.AddQualificationConversionStep(
             cv1T1, DestType->isRValueReferenceType() ? VK_XValue : VK_LValue);
+      else if (S.getLangOpts().CPlusPlus20 &&
+               isa<IncompleteArrayType>(T1->getUnqualifiedDesugaredType()) &&
+               DestType->isRValueReferenceType()) {
+        // [dcl.init.list] p3.10
+        // unless T is “reference to array of unknown bound of U”, in which case
+        // the type of the prvalue is the type of x in the declaration U x[] H,
+        // where H is the initializer list.
+        Sequence.AddQualificationConversionStep(cv1T1, VK_XValue);
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Fznamznon wrote:

@HerrCai0907 I see what you mean and what the patch accomplishes. But my confusion was, why in order to do that `AddQualificationConversionStep` is called? IMO this is just to convert cv-qualifiers. The goal is to convert one array type to another, right?

https://github.com/llvm/llvm-project/pull/65918