properly fill a promoted's required_consts

then we can also make all_required_consts_are_checked a constant instead of a function

2 files changed, 11 insertions, 22 deletions

diff --git a/compiler/rustc_mir_transform/src/promote_consts.rs b/compiler/rustc_mir_transform/src/promote_consts.rs
index 928a23006fa..689a547689a 100644
--- a/compiler/rustc_mir_transform/src/promote_consts.rs
+++ b/compiler/rustc_mir_transform/src/promote_consts.rs
@@ -951,6 +951,14 @@ impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> {
             *local = self.promote_temp(*local);
         }
     }
+
+    fn visit_constant(&mut self, constant: &mut ConstOperand<'tcx>, _location: Location) {
+        if constant.const_.is_required_const() {
+            self.promoted.required_consts.push(*constant);
+        }
+
+        // Skipping `super_constant` as the visitor is otherwise only looking for locals.
+    }
 }
 
 fn promote_candidates<'tcx>(
@@ -995,11 +1003,6 @@ fn promote_candidates<'tcx>(
             None,
             body.tainted_by_errors,
         );
-        // We keep `required_consts` of the new MIR body empty. All consts mentioned here have
-        // already been added to the parent MIR's `required_consts` (that is computed before
-        // promotion), and no matter where this promoted const ends up, our parent MIR must be
-        // somewhere in the reachable dependency chain so we can rely on its required consts being
-        // evaluated.
         promoted.phase = MirPhase::Analysis(AnalysisPhase::Initial);
 
         let promoter = Promoter {
@@ -1012,6 +1015,7 @@ fn promote_candidates<'tcx>(
             add_to_required: false,
         };
 
+        // `required_consts` of the promoted itself gets filled while building the MIR body.
         let mut promoted = promoter.promote_candidate(candidate, promotions.len());
         promoted.source.promoted = Some(promotions.next_index());
         promotions.push(promoted);
diff --git a/compiler/rustc_mir_transform/src/required_consts.rs b/compiler/rustc_mir_transform/src/required_consts.rs
index f0c63a6648c..71ac929d35e 100644
--- a/compiler/rustc_mir_transform/src/required_consts.rs
+++ b/compiler/rustc_mir_transform/src/required_consts.rs
@@ -1,6 +1,5 @@
 use rustc_middle::mir::visit::Visitor;
-use rustc_middle::mir::{Const, ConstOperand, Location};
-use rustc_middle::ty;
+use rustc_middle::mir::{ConstOperand, Location};
 
 pub struct RequiredConstsVisitor<'a, 'tcx> {
     required_consts: &'a mut Vec<ConstOperand<'tcx>>,
@@ -14,21 +13,7 @@ impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
 
 impl<'tcx> Visitor<'tcx> for RequiredConstsVisitor<'_, 'tcx> {
     fn visit_constant(&mut self, constant: &ConstOperand<'tcx>, _: Location) {
-        // Only unevaluated consts have to be added to `required_consts` as only those can possibly
-        // still have latent const-eval errors.
-        let is_required = match constant.const_ {
-            Const::Ty(c) => match c.kind() {
-                ty::ConstKind::Value(_) => false, // already a value, cannot error
-                ty::ConstKind::Param(_) | ty::ConstKind::Error(_) => true, // these are errors or could be replaced by errors
-                _ => bug!(
-                    "only ConstKind::Param/Value/Error should be encountered here, got {:#?}",
-                    c
-                ),
-            },
-            Const::Unevaluated(..) => true,
-            Const::Val(..) => false, // already a value, cannot error
-        };
-        if is_required {
+        if constant.const_.is_required_const() {
             self.required_consts.push(*constant);
         }
     }