1 files changed, 32 insertions, 11 deletions
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index 6e4ab2a35c3..b7e3ca571e1 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -8,8 +8,9 @@
 use rustc_hir::{def::DefKind, def_id::DefId, ConstContext};
 use rustc_index::bit_set::FiniteBitSet;
 use rustc_middle::mir::{
+    self,
     visit::{TyContext, Visitor},
-    Local, LocalDecl, Location,
+    Constant, ConstantKind, Local, LocalDecl, Location,
 };
 use rustc_middle::ty::{
     self,
@@ -33,7 +34,6 @@ pub fn provide(providers: &mut Providers) {
 ///
 /// Returns a bitset where bits representing unused parameters are set (`is_empty` indicates all
 /// parameters are used).
-#[instrument(level = "debug", skip(tcx))]
 fn unused_generic_params<'tcx>(
     tcx: TyCtxt<'tcx>,
     instance: ty::InstanceDef<'tcx>,
@@ -171,6 +171,7 @@ fn mark_used_by_default_parameters<'tcx>(
         | DefKind::AnonConst
         | DefKind::InlineConst
         | DefKind::OpaqueTy
+        | DefKind::ImplTraitPlaceholder
         | DefKind::Field
         | DefKind::LifetimeParam
         | DefKind::GlobalAsm
@@ -270,8 +271,15 @@ impl<'a, 'tcx> Visitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
         self.super_local_decl(local, local_decl);
     }
 
-    fn visit_const(&mut self, c: Const<'tcx>, _: Location) {
-        c.visit_with(self);
+    fn visit_constant(&mut self, ct: &Constant<'tcx>, location: Location) {
+        match ct.literal {
+            ConstantKind::Ty(c) => {
+                c.visit_with(self);
+            }
+            ConstantKind::Val(_, ty) | ConstantKind::Unevaluated(_, ty) => {
+                Visitor::visit_ty(self, ty, TyContext::Location(location))
+            }
+        }
     }
 
     fn visit_ty(&mut self, ty: Ty<'tcx>, _: TyContext) {
@@ -292,7 +300,24 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.unused_parameters.clear(param.index);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted: Some(p)})
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs })
+                if matches!(self.tcx.def_kind(def.did), DefKind::AnonConst) =>
+            {
+                self.visit_child_body(def.did, substs);
+                ControlFlow::CONTINUE
+            }
+            _ => c.super_visit_with(self),
+        }
+    }
+
+    fn visit_mir_const(&mut self, constant: ConstantKind<'tcx>) -> ControlFlow<Self::BreakTy> {
+        if !constant.has_param_types_or_consts() {
+            return ControlFlow::CONTINUE;
+        }
+
+        match constant {
+            ConstantKind::Ty(ct) => ct.visit_with(self),
+            ConstantKind::Unevaluated(mir::UnevaluatedConst { def, substs: _, promoted: Some(p) }, _)
                 // Avoid considering `T` unused when constants are of the form:
                 //   `<Self as Foo<T>>::foo::promoted[p]`
                 if self.def_id == def.did && !self.tcx.generics_of(def.did).has_self =>
@@ -303,13 +328,9 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.visit_body(&promoted[p]);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(uv)
-                if matches!(self.tcx.def_kind(uv.def.did), DefKind::AnonConst | DefKind::InlineConst) =>
-            {
-                self.visit_child_body(uv.def.did, uv.substs);
-                ControlFlow::CONTINUE
+            ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => {
+                constant.super_visit_with(self)
             }
-            _ => c.super_visit_with(self),
         }
     }