Auto merge of #96116 - ouz-a:mir-opt, r=oli-obk

Make derefer work everwhere

Follow up work on previous PR's #95649 and #95857.

r? rust-lang/mir-opt

_Co-Authored-By: `@oli-obk_`

diff --cc src/test/mir-opt/early_otherwise_branch_soundness.no_downcast.EarlyOtherwiseBranch.diff
Simple merge