[clang-tools-extra] [clang-tidy] Fix crash on pointer arithmetic with an incomplete type in bugprone-pointer-arithmetic-on-polymorphic-object (PR #215724)

[via cfe-commits]

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@@ -139,3 +139,15 @@ void typeAliases(BaseAlias *b, DerivedAlias *d, FinalDerivedAlias *fd,
   fdp += 1;
   // no-warning
 }
+
+// Regression test: pointer arithmetic on a pointer to an incomplete type must
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Hao-Chen2337 wrote:

Done, added the release note as requested and reduced to a one-line comment. 

https://github.com/llvm/llvm-project/pull/215724