[clang] [Clang]Check for a valid Index in array before getting it (PR #172399)

[Mariya Podchishchaeva via cfe-commits]

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@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -verify %s
+
+// ref-no-diagnostics
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Fznamznon wrote:

I think since there is no `ref` prefix passed to `verify` option that is not really required.
```suggestion
```

https://github.com/llvm/llvm-project/pull/172399