5 files changed, 31 insertions, 16 deletions
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index 36d623fd93e..9487692662b 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -228,6 +228,7 @@ use rustc_middle::ty::{
     TypeVisitableExt, VtblEntry,
 };
 use rustc_middle::ty::{GenericArgKind, GenericArgs};
+use rustc_middle::{bug, span_bug};
 use rustc_session::config::EntryFnType;
 use rustc_session::Limit;
 use rustc_span::source_map::{dummy_spanned, respan, Spanned};
@@ -235,6 +236,7 @@ use rustc_span::symbol::{sym, Ident};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_target::abi::Size;
 use std::path::PathBuf;
+use tracing::{debug, instrument, trace};
 
 use crate::errors::{
     self, EncounteredErrorWhileInstantiating, NoOptimizedMir, RecursionLimit, TypeLengthLimit,
@@ -966,13 +968,14 @@ fn visit_instance_use<'tcx>(
         ty::InstanceDef::ThreadLocalShim(..) => {
             bug!("{:?} being reified", instance);
         }
-        ty::InstanceDef::DropGlue(_, None) => {
+        ty::InstanceDef::DropGlue(_, None) | ty::InstanceDef::AsyncDropGlueCtorShim(_, None) => {
             // Don't need to emit noop drop glue if we are calling directly.
             if !is_direct_call {
                 output.push(create_fn_mono_item(tcx, instance, source));
             }
         }
         ty::InstanceDef::DropGlue(_, Some(_))
+        | ty::InstanceDef::AsyncDropGlueCtorShim(_, Some(_))
         | ty::InstanceDef::VTableShim(..)
         | ty::InstanceDef::ReifyShim(..)
         | ty::InstanceDef::ClosureOnceShim { .. }
@@ -1427,10 +1430,19 @@ impl<'v> RootCollector<'_, 'v> {
         match self.tcx.def_kind(id.owner_id) {
             DefKind::Enum | DefKind::Struct | DefKind::Union => {
                 if self.strategy == MonoItemCollectionStrategy::Eager
-                    && self.tcx.generics_of(id.owner_id).count() == 0
+                    && self.tcx.generics_of(id.owner_id).is_empty()
                 {
                     debug!("RootCollector: ADT drop-glue for `{id:?}`",);
 
+                    // This type is impossible to instantiate, so we should not try to
+                    // generate a `drop_in_place` instance for it.
+                    if self.tcx.instantiate_and_check_impossible_predicates((
+                        id.owner_id.to_def_id(),
+                        ty::List::empty(),
+                    )) {
+                        return;
+                    }
+
                     let ty = self.tcx.type_of(id.owner_id.to_def_id()).no_bound_vars().unwrap();
                     visit_drop_use(self.tcx, ty, true, DUMMY_SP, self.output);
                 }
diff --git a/compiler/rustc_monomorphize/src/collector/move_check.rs b/compiler/rustc_monomorphize/src/collector/move_check.rs
index 4cc7275ab80..851f86e86b8 100644
--- a/compiler/rustc_monomorphize/src/collector/move_check.rs
+++ b/compiler/rustc_monomorphize/src/collector/move_check.rs
@@ -1,4 +1,5 @@
 use rustc_session::lint::builtin::LARGE_ASSIGNMENTS;
+use tracing::debug;
 
 use super::*;
 use crate::errors::LargeAssignmentsLint;
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index 2a91d69529a..b298fe5813f 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -2,12 +2,8 @@
 #![feature(is_sorted)]
 #![allow(rustc::potential_query_instability)]
 
-#[macro_use]
-extern crate tracing;
-#[macro_use]
-extern crate rustc_middle;
-
 use rustc_hir::lang_items::LangItem;
+use rustc_middle::bug;
 use rustc_middle::query::{Providers, TyCtxtAt};
 use rustc_middle::traits;
 use rustc_middle::ty::adjustment::CustomCoerceUnsized;
@@ -33,10 +29,9 @@ fn custom_coerce_unsize_info<'tcx>(
     source_ty: Ty<'tcx>,
     target_ty: Ty<'tcx>,
 ) -> Result<CustomCoerceUnsized, ErrorGuaranteed> {
-    let trait_ref = ty::TraitRef::from_lang_item(
+    let trait_ref = ty::TraitRef::new(
         tcx.tcx,
-        LangItem::CoerceUnsized,
-        tcx.span,
+        tcx.require_lang_item(LangItem::CoerceUnsized, Some(tcx.span)),
         [source_ty, target_ty],
     );
 
diff --git a/compiler/rustc_monomorphize/src/partitioning.rs b/compiler/rustc_monomorphize/src/partitioning.rs
index 5a92657cb40..21d52004728 100644
--- a/compiler/rustc_monomorphize/src/partitioning.rs
+++ b/compiler/rustc_monomorphize/src/partitioning.rs
@@ -103,6 +103,7 @@ use rustc_data_structures::sync;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdSet, LOCAL_CRATE};
 use rustc_hir::definitions::DefPathDataName;
+use rustc_middle::bug;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::middle::exported_symbols::{SymbolExportInfo, SymbolExportLevel};
 use rustc_middle::mir::mono::{
@@ -115,6 +116,7 @@ use rustc_middle::ty::{self, visit::TypeVisitableExt, InstanceDef, TyCtxt};
 use rustc_session::config::{DumpMonoStatsFormat, SwitchWithOptPath};
 use rustc_session::CodegenUnits;
 use rustc_span::symbol::Symbol;
+use tracing::debug;
 
 use crate::collector::UsageMap;
 use crate::collector::{self, MonoItemCollectionStrategy};
@@ -625,7 +627,8 @@ fn characteristic_def_id_of_mono_item<'tcx>(
                 | ty::InstanceDef::Virtual(..)
                 | ty::InstanceDef::CloneShim(..)
                 | ty::InstanceDef::ThreadLocalShim(..)
-                | ty::InstanceDef::FnPtrAddrShim(..) => return None,
+                | ty::InstanceDef::FnPtrAddrShim(..)
+                | ty::InstanceDef::AsyncDropGlueCtorShim(..) => return None,
             };
 
             // If this is a method, we want to put it into the same module as
@@ -769,7 +772,9 @@ fn mono_item_visibility<'tcx>(
     };
 
     let def_id = match instance.def {
-        InstanceDef::Item(def_id) | InstanceDef::DropGlue(def_id, Some(_)) => def_id,
+        InstanceDef::Item(def_id)
+        | InstanceDef::DropGlue(def_id, Some(_))
+        | InstanceDef::AsyncDropGlueCtorShim(def_id, Some(_)) => def_id,
 
         // We match the visibility of statics here
         InstanceDef::ThreadLocalShim(def_id) => {
@@ -786,6 +791,7 @@ fn mono_item_visibility<'tcx>(
         | InstanceDef::ConstructCoroutineInClosureShim { .. }
         | InstanceDef::CoroutineKindShim { .. }
         | InstanceDef::DropGlue(..)
+        | InstanceDef::AsyncDropGlueCtorShim(..)
         | InstanceDef::CloneShim(..)
         | InstanceDef::FnPtrAddrShim(..) => return Visibility::Hidden,
     };
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index 6d237df073f..dc13766d145 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -18,6 +18,7 @@ use rustc_middle::ty::{
     GenericArgsRef, Ty, TyCtxt, UnusedGenericParams,
 };
 use rustc_span::symbol::sym;
+use tracing::{debug, instrument};
 
 use crate::errors::UnusedGenericParamsHint;
 
@@ -51,7 +52,7 @@ fn unused_generic_params<'tcx>(
     debug!(?generics);
 
     // Exit early when there are no parameters to be unused.
-    if generics.count() == 0 {
+    if generics.is_empty() {
         return UnusedGenericParams::new_all_used();
     }
 
@@ -131,7 +132,7 @@ fn mark_used_by_default_parameters<'tcx>(
 ) {
     match tcx.def_kind(def_id) {
         DefKind::Closure => {
-            for param in &generics.params {
+            for param in &generics.own_params {
                 debug!(?param, "(closure/gen)");
                 unused_parameters.mark_used(param.index);
             }
@@ -165,7 +166,7 @@ fn mark_used_by_default_parameters<'tcx>(
         | DefKind::LifetimeParam
         | DefKind::GlobalAsm
         | DefKind::Impl { .. } => {
-            for param in &generics.params {
+            for param in &generics.own_params {
                 debug!(?param, "(other)");
                 if let ty::GenericParamDefKind::Lifetime = param.kind {
                     unused_parameters.mark_used(param.index);
@@ -202,7 +203,7 @@ fn emit_unused_generic_params_error<'tcx>(
     let mut param_names = Vec::new();
     let mut next_generics = Some(generics);
     while let Some(generics) = next_generics {
-        for param in &generics.params {
+        for param in &generics.own_params {
             if unused_parameters.is_unused(param.index) {
                 debug!(?param);
                 let def_span = tcx.def_span(param.def_id);