[clang] Fix UPCAddressofArraySubscriptGadget::getClaimedVarUseSites() (PR #88406)

[Louis Dionne via cfe-commits]

ldionne wrote:

I just approved the CI runs. I think this can be merged once the CI is all green. Whoever sees this first with push access can merge.

https://github.com/llvm/llvm-project/pull/88406