[clang] [Clang]fix dependent qualified base member lookup crash (PR #199403)

[Matheus Izvekov via cfe-commits]

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@@ -126,6 +126,11 @@ bool CXXRecordDecl::forallBases(ForallBasesCallback BaseMatches) const {
   SmallVector<const CXXRecordDecl*, 8> Queue;
 
   const CXXRecordDecl *Record = this;
+
+  if (const CXXRecordDecl *Def = getDefinition())
+    Record = Def;
+  else if (!dataPtr())
+    return false;
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mizvekov wrote:

I don't get why this is still here, if we discussed this and you agreed the check is unnecessary.

Moreover, `bases()` is one of the CXXRecordDecl properties which is managed through the `data` pointer, so retrieving the definition is unnecessary.

https://github.com/llvm/llvm-project/pull/199403