From b7f2b1cd5cd08e4805bb3df0e8153445acfb04c7 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Thu, 1 Dec 2022 16:41:49 +0100 Subject: [PATCH] clarify comment on Deref promotion --- compiler/rustc_const_eval/src/transform/promote_consts.rs | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs index f48bcd9080966..6777fae74f1ca 100644 --- a/compiler/rustc_const_eval/src/transform/promote_consts.rs +++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs @@ -318,14 +318,14 @@ impl<'tcx> Validator<'_, 'tcx> { match elem { ProjectionElem::Deref => { let mut promotable = false; + // When a static is used by-value, that gets desugared to `*STATIC_ADDR`, + // and we need to be able to promote this. So check if this deref matches + // that specific pattern. + // We need to make sure this is a `Deref` of a local with no further projections. // Discussion can be found at // https://github.com/rust-lang/rust/pull/74945#discussion_r463063247 if let Some(local) = place_base.as_local() { - // This is a special treatment for cases like *&STATIC where STATIC is a - // global static variable. - // This pattern is generated only when global static variables are directly - // accessed and is qualified for promotion safely. if let TempState::Defined { location, .. } = self.temps[local] { let def_stmt = self.body[location.block] .statements