aligns the behavior to that prior to #118311

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -2083,13 +2083,9 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                         .opt_item_name(self.mir_def_id().to_def_id())
                         .map(|name| format!("function `{name}`"))
                         .unwrap_or_else(|| {
-                            match &self.infcx.tcx.def_kind(self.mir_def_id()) {
-                                DefKind::Closure
-                                    if self
-                                        .infcx
-                                        .tcx
-                                        .is_coroutine(self.mir_def_id().to_def_id()) =>
-                                {
+                            let def_id = self.mir_def_id();
+                            match &self.infcx.tcx.def_kind(def_id) {
+                                DefKind::Closure if self.infcx.tcx.is_coroutine(def_id) => {
                                     "enclosing coroutine"
                                 }
                                 DefKind::Closure => "enclosing closure",

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -2663,9 +2663,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         let typeck_root_args = ty::GenericArgs::identity_for_item(tcx, typeck_root_def_id);
 
         let parent_args = match tcx.def_kind(def_id) {
-            DefKind::Closure if tcx.is_coroutine(def_id.to_def_id()) => {
-                args.as_coroutine().parent_args()
-            }
+            DefKind::Closure if tcx.is_coroutine(def_id) => args.as_coroutine().parent_args(),
             DefKind::Closure => args.as_closure().parent_args(),
             DefKind::InlineConst => args.as_inline_const().parent_args(),
             other => bug!("unexpected item {:?}", other),

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1446,7 +1446,7 @@ fn opaque_type_cycle_error(
                         label_match(capture.place.ty(), capture.get_path_span(tcx));
                     }
                     // Label any coroutine locals that capture the opaque
-                    if tcx.is_coroutine(closure_def_id)
+                    if tcx.is_coroutine(closure_local_did)
                         && let Some(coroutine_layout) = tcx.mir_coroutine_witnesses(closure_def_id)
                     {
                         for interior_ty in &coroutine_layout.field_tys {
@@ -1467,7 +1467,7 @@ pub(super) fn check_coroutine_obligations(
     tcx: TyCtxt<'_>,
     def_id: LocalDefId,
 ) -> Result<(), ErrorGuaranteed> {
-    debug_assert!(tcx.is_coroutine(def_id.to_def_id()));
+    debug_assert!(tcx.is_coroutine(def_id));
 
     let typeck = tcx.typeck(def_id);
     let param_env = tcx.param_env(def_id);

compiler/rustc_interface/src/passes.rs

@@ -762,7 +762,7 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
     });
 
     tcx.hir().par_body_owners(|def_id| {
-        if tcx.is_coroutine(def_id.to_def_id()) {
+        if tcx.is_coroutine(def_id) {
             tcx.ensure().mir_coroutine_witnesses(def_id);
             tcx.ensure().check_coroutine_obligations(def_id);
         }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -875,7 +875,7 @@ fn should_encode_span(def_kind: DefKind) -> bool {
     }
 }
 
-fn should_encode_attrs(def_kind: DefKind) -> bool {
+fn should_encode_attrs(def_kind: DefKind, is_coroutine: bool) -> bool {
     match def_kind {
         DefKind::Mod
         | DefKind::Struct
@@ -899,7 +899,7 @@ fn should_encode_attrs(def_kind: DefKind) -> bool {
         // closures from upstream crates, too. This is used by
         // https://github.com/model-checking/kani and is not a performance
         // or maintenance issue for us.
-        DefKind::Closure => true,
+        DefKind::Closure => !is_coroutine,
         DefKind::TyParam
         | DefKind::ConstParam
         | DefKind::Ctor(..)
@@ -1058,7 +1058,7 @@ fn should_encode_mir(
         | DefKind::Static(..)
         | DefKind::Const => (true, false),
         // Coroutines require optimized MIR to compute layout.
-        DefKind::Closure if tcx.is_coroutine(def_id.to_def_id()) => (false, true),
+        DefKind::Closure if tcx.is_coroutine(def_id) => (false, true),
         // Full-fledged functions + closures
         DefKind::AssocFn | DefKind::Fn | DefKind::Closure => {
             let generics = tcx.generics_of(def_id);
@@ -1241,11 +1241,11 @@ fn should_encode_fn_sig(def_kind: DefKind) -> bool {
     }
 }
 
-fn should_encode_constness(def_kind: DefKind) -> bool {
+fn should_encode_constness(def_kind: DefKind, is_coroutine: bool) -> bool {
     match def_kind {
+        DefKind::Closure => !is_coroutine,
         DefKind::Fn
         | DefKind::AssocFn
-        | DefKind::Closure
         | DefKind::Impl { of_trait: true }
         | DefKind::Variant
         | DefKind::Ctor(..) => true,
@@ -1358,12 +1358,13 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         for local_id in tcx.iter_local_def_id() {
             let def_id = local_id.to_def_id();
             let def_kind = tcx.def_kind(local_id);
+            let is_coroutine = def_kind == DefKind::Closure && tcx.is_coroutine(local_id);
             self.tables.def_kind.set_some(def_id.index, def_kind);
             if should_encode_span(def_kind) {
                 let def_span = tcx.def_span(local_id);
                 record!(self.tables.def_span[def_id] <- def_span);
             }
-            if should_encode_attrs(def_kind) {
+            if should_encode_attrs(def_kind, is_coroutine) {
                 self.encode_attrs(local_id);
             }
             if should_encode_expn_that_defined(def_kind) {
@@ -1418,7 +1419,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             if should_encode_type(tcx, local_id, def_kind) && !anon_const_without_hir {
                 record!(self.tables.type_of[def_id] <- self.tcx.type_of(def_id));
             }
-            if should_encode_constness(def_kind) {
+            if should_encode_constness(def_kind, is_coroutine) {
                 self.tables.constness.set_some(def_id.index, self.tcx.constness(def_id));
             }
             if let DefKind::Fn | DefKind::AssocFn = def_kind {
@@ -1639,7 +1640,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.closure_saved_names_of_captured_variables[def_id.to_def_id()]
                     <- tcx.closure_saved_names_of_captured_variables(def_id));
 
-                if self.tcx.is_coroutine(def_id.to_def_id())
+                if self.tcx.is_coroutine(def_id)
                     && let Some(witnesses) = tcx.mir_coroutine_witnesses(def_id)
                 {
                     record!(self.tables.mir_coroutine_witnesses[def_id.to_def_id()] <- witnesses);
@@ -1666,7 +1667,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             }
             record!(self.tables.promoted_mir[def_id.to_def_id()] <- tcx.promoted_mir(def_id));
 
-            if self.tcx.is_coroutine(def_id.to_def_id())
+            if self.tcx.is_coroutine(def_id)
                 && let Some(witnesses) = tcx.mir_coroutine_witnesses(def_id)
             {
                 record!(self.tables.mir_coroutine_witnesses[def_id.to_def_id()] <- witnesses);

compiler/rustc_middle/src/ty/context.rs

@@ -843,7 +843,7 @@ impl<'tcx> TyCtxt<'tcx> {
         self.diagnostic_items(did.krate).name_to_id.get(&name) == Some(&did)
     }
 
-    pub fn is_coroutine(self, def_id: DefId) -> bool {
+    pub fn is_coroutine(self, def_id: LocalDefId) -> bool {
         self.coroutine_kind(def_id).is_some()
     }
 

compiler/rustc_mir_build/src/build/mod.rs

@@ -480,7 +480,9 @@ fn construct_fn<'tcx>(
     };
 
     let mut abi = fn_sig.abi;
-    if let DefKind::Closure = tcx.def_kind(fn_def) {
+    if let DefKind::Closure = tcx.def_kind(fn_def)
+        && !tcx.is_coroutine(fn_def)
+    {
         // HACK(eddyb) Avoid having RustCall on closures,
         // as it adds unnecessary (and wrong) auto-tupling.
         abi = Abi::Rust;

compiler/rustc_mir_build/src/thir/cx/mod.rs

@@ -37,7 +37,7 @@ pub(crate) fn thir_body(
 
         // The resume argument may be missing, in that case we need to provide it here.
         // It will always be `()` in this case.
-        if tcx.is_coroutine(owner_def.to_def_id()) && body.params.is_empty() {
+        if tcx.is_coroutine(owner_def) && body.params.is_empty() {
             cx.thir.params.push(Param {
                 ty: Ty::new_unit(tcx),
                 pat: None,
@@ -119,7 +119,7 @@ impl<'tcx> Cx<'tcx> {
 
     fn closure_env_param(&self, owner_def: LocalDefId, owner_id: HirId) -> Option<Param<'tcx>> {
         match self.tcx.def_kind(owner_def) {
-            DefKind::Closure if self.tcx.is_coroutine(owner_def.to_def_id()) => {
+            DefKind::Closure if self.tcx.is_coroutine(owner_def) => {
                 let coroutine_ty = self.typeck_results.node_type(owner_id);
                 let coroutine_param = Param {
                     ty: coroutine_ty,

compiler/rustc_mir_transform/src/const_prop_lint.rs

@@ -61,7 +61,7 @@ impl<'tcx> MirLint<'tcx> for ConstPropLint {
 
         // FIXME(welseywiser) const prop doesn't work on coroutines because of query cycles
         // computing their layout.
-        if tcx.is_coroutine(def_id.to_def_id()) {
+        if def_kind == DefKind::Closure && tcx.is_coroutine(def_id) {
             trace!("ConstPropLint skipped for coroutine {:?}", def_id);
             return;
         }

compiler/rustc_mir_transform/src/cross_crate_inline.rs

@@ -42,6 +42,14 @@ fn cross_crate_inlinable(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
         _ => {}
     }
 
+    // This just reproduces the logic from Instance::requires_inline.
+    match tcx.def_kind(def_id) {
+        DefKind::Closure if tcx.is_coroutine(def_id) => return false,
+        DefKind::Ctor(..) | DefKind::Closure => return true,
+        DefKind::Fn | DefKind::AssocFn => {}
+        _ => return false,
+    }
+
     // Don't do any inference when incremental compilation is enabled; the additional inlining that
     // inference permits also creates more work for small edits.
     if tcx.sess.opts.incremental.is_some() {

compiler/rustc_mir_transform/src/lib.rs

@@ -324,6 +324,7 @@ fn mir_promoted(
     // Also this means promotion can rely on all const checks having been done.
 
     let const_qualifs = match tcx.def_kind(def) {
+        DefKind::Closure if tcx.is_coroutine(def) => ConstQualifs::default(),
         DefKind::Fn | DefKind::AssocFn | DefKind::Closure
             if tcx.constness(def) == hir::Constness::Const
                 || tcx.is_const_default_method(def.to_def_id()) =>
@@ -396,7 +397,7 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
 /// mir borrowck *before* doing so in order to ensure that borrowck can be run and doesn't
 /// end up missing the source MIR due to stealing happening.
 fn mir_drops_elaborated_and_const_checked(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> {
-    if tcx.is_coroutine(def.to_def_id()) {
+    if tcx.is_coroutine(def) {
         tcx.ensure_with_value().mir_coroutine_witnesses(def);
     }
     let mir_borrowck = tcx.mir_borrowck(def);