f71b3e2b46
Document behavior of `MaybeLiveLocals` regarding enums and field-senstivity This arose from a [discussion on Zulip](https://rust-lang.zulipchat.com/#narrow/stream/189540-t-compiler.2Fwg-mir-opt/topic/MaybeLiveLocals.20and.20Discriminants) where a new contributor attempted to implement a dead-store elimination pass using this analysis. They ran into a nasty hack around `SetDiscriminant` the effect of which is to lets handle assignments of literals to enum-typed locals (e.g. `x = Some(4)`) correctly. This took me a while to figure out. Document this oddity, so the next person will have an easier time, and add a test to enshrine the current behavior. r? ``@tmiasko`` |
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Cargo.toml |