Auto merge of #118411 - bvanjoi:merge_coroutinue_into_closure_2, r=<try>

aligns the behavior to that prior to #118311

After #118311, it seems that due to an oversight some alignments were unintentionally omitted, possibly leading the code into different branches. This PR attempts to restore those alignments and aims to fix the regression reported at #118319 (comment)

Author: bors

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -862,7 +862,7 @@ 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
@@ -886,7 +886,7 @@ 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(..)
@@ -1228,11 +1228,11 @@ 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,
@@ -1345,12 +1345,13 @@ 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(def_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) {
@@ -1405,7 +1406,7 @@ 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 {

compiler/rustc_middle/src/ty/mod.rs

@@ -2467,10 +2467,16 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn is_const_fn_raw(self, def_id: DefId) -> bool {
-        matches!(
-            self.def_kind(def_id),
-            DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..) | DefKind::Closure
-        ) && self.constness(def_id) == hir::Constness::Const
+        let def_kind = self.def_kind(def_id);
+        if def_kind == DefKind::Closure
+            && !self.is_coroutine(def_id)
+            && self.constness(def_id) == hir::Constness::Const
+        {
+            true
+        } else {
+            matches!(def_kind, DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..))
+                && self.constness(def_id) == hir::Constness::Const
+        }
     }
 
     #[inline]

compiler/rustc_mir_build/src/build/mod.rs

@@ -474,7 +474,9 @@ 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.to_def_id())
+    {
         // HACK(eddyb) Avoid having RustCall on closures,
         // as it adds unnecessary (and wrong) auto-tupling.
         abi = Abi::Rust;

compiler/rustc_mir_transform/src/cross_crate_inline.rs

@@ -32,6 +32,7 @@ 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.to_def_id()) => return false,
         DefKind::Ctor(..) | DefKind::Closure => return true,
         DefKind::Fn | DefKind::AssocFn => {}
         _ => return false,

compiler/rustc_mir_transform/src/lib.rs

@@ -323,6 +323,7 @@ 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.to_def_id()) => ConstQualifs::default(),
         DefKind::Fn | DefKind::AssocFn | DefKind::Closure
             if tcx.constness(def) == hir::Constness::Const
                 || tcx.is_const_default_method(def.to_def_id()) =>