AsyncDrop trait without sync Drop generates an error

3 files changed, 20 insertions, 1 deletions

diff --git a/compiler/rustc_hir_analysis/messages.ftl b/compiler/rustc_hir_analysis/messages.ftl
index f768bd157ab..bd2252c1bf8 100644
--- a/compiler/rustc_hir_analysis/messages.ftl
+++ b/compiler/rustc_hir_analysis/messages.ftl
@@ -46,6 +46,9 @@ hir_analysis_associated_type_trait_uninferred_generic_params = cannot use the {$
 
 hir_analysis_associated_type_trait_uninferred_generic_params_multipart_suggestion = use a fully qualified path with explicit lifetimes
 
+hir_analysis_async_drop_without_sync_drop = `AsyncDrop` impl without `Drop` impl
+    .help = type implementing `AsyncDrop` trait must also implement `Drop` trait to be used in sync context and unwinds
+
 hir_analysis_auto_deref_reached_recursion_limit = reached the recursion limit while auto-dereferencing `{$ty}`
     .label = deref recursion limit reached
     .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index c5c7e6b2aa7..de8cbc3a57f 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -113,7 +113,15 @@ pub fn provide(providers: &mut Providers) {
 }
 
 fn adt_destructor(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<ty::Destructor> {
-    tcx.calculate_dtor(def_id, always_applicable::check_drop_impl)
+    let dtor = tcx.calculate_dtor(def_id, always_applicable::check_drop_impl);
+    if dtor.is_none() && tcx.features().async_drop() {
+        if let Some(async_dtor) = adt_async_destructor(tcx, def_id) {
+            // When type has AsyncDrop impl, but doesn't have Drop impl, generate error
+            let span = tcx.def_span(async_dtor.impl_did);
+            tcx.dcx().emit_err(errors::AsyncDropWithoutSyncDrop { span });
+        }
+    }
+    dtor
 }
 
 fn adt_async_destructor(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<ty::AsyncDestructor> {
diff --git a/compiler/rustc_hir_analysis/src/errors.rs b/compiler/rustc_hir_analysis/src/errors.rs
index 8de2aec95a7..318aaab50f4 100644
--- a/compiler/rustc_hir_analysis/src/errors.rs
+++ b/compiler/rustc_hir_analysis/src/errors.rs
@@ -1712,3 +1712,11 @@ pub(crate) struct AbiCustomClothedFunction {
     )]
     pub naked_span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_async_drop_without_sync_drop)]
+#[help]
+pub(crate) struct AsyncDropWithoutSyncDrop {
+    #[primary_span]
+    pub span: Span,
+}