[clang] [lldb] [BoundsSafety] Introduce LateParsedAttrType AST placeholder type (PR #204125)

[Dan Liew via cfe-commits]

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@@ -1843,6 +1842,13 @@ ASTNodeImporter::VisitCountAttributedType(const CountAttributedType *T) {
       ArrayRef(CoupledDecls));
 }
 
+ExpectedType
+ASTNodeImporter::VisitLateParsedAttrType(const LateParsedAttrType *T) {
+  // LateParsedAttrType is a transient placeholder that should not normally
+  // appear during AST import. Import as the wrapped type.
+  return import(T->getWrappedType());
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delcypher wrote:

Seeing as we have `lvm_unreachable("unreachable for serialization")` for AST serialization should we mirror that here for AST import?

https://github.com/llvm/llvm-project/pull/204125