From accbfccd597b332a36d6d22335d1d7d8e9507619 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Wed, 11 Mar 2026 07:22:26 +0000
Subject: [PATCH 01/13] Unconditionally error when trying to create a const
 coroutine

---
 compiler/rustc_ast_lowering/src/expr.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 4a2992038003c..e86a2f33b87b1 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -231,6 +231,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         e.id,
                         expr_hir_id,
                         *coroutine_kind,
+                        *constness,
                         fn_decl,
                         body,
                         *fn_decl_span,
@@ -1158,6 +1159,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         closure_id: NodeId,
         closure_hir_id: HirId,
         coroutine_kind: CoroutineKind,
+        constness: Const,
         decl: &FnDecl,
         body: &Expr,
         fn_decl_span: Span,
@@ -1204,6 +1206,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let fn_decl =
             self.lower_fn_decl(&decl, closure_id, fn_decl_span, FnDeclKind::Closure, None);
 
+        if let Const::Yes(span) = constness {
+            self.dcx().span_err(span, "const coroutines are not supported");
+        }
+
         let c = self.arena.alloc(hir::Closure {
             def_id: closure_def_id,
             binder: binder_clause,
@@ -1217,7 +1223,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
             // knows that a `FnDecl` output type like `-> &str` actually means
             // "coroutine that returns &str", rather than directly returning a `&str`.
             kind: hir::ClosureKind::CoroutineClosure(coroutine_desugaring),
-            constness: hir::Constness::NotConst,
+            constness: self.lower_constness(constness),
         });
         hir::ExprKind::Closure(c)
     }

From ae4ddd2806b7abcabf33fb6ef61f01c5e675c8b9 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Thu, 12 Mar 2026 08:44:28 +0000
Subject: [PATCH 02/13] Reject const closures outside const contexts

---
 compiler/rustc_ast_lowering/src/expr.rs       | 11 ++++++--
 compiler/rustc_ast_lowering/src/item.rs       | 24 +++++++++++++++---
 compiler/rustc_ast_lowering/src/lib.rs        |  2 ++
 .../const-closure-issue-125866-error.rs       |  4 +--
 .../const-closure-issue-125866-pass.rs        | 25 -------------------
 ...closure-const_trait_impl-ice-113381.stderr |  7 +++---
 tests/ui/traits/const-traits/gate.rs          |  6 ++---
 tests/ui/traits/const-traits/gate.stderr      | 14 +++++------
 ...-const-op-const-closure-non-const-outer.rs |  2 +-
 ...st-op-const-closure-non-const-outer.stderr |  7 +++---
 10 files changed, 50 insertions(+), 52 deletions(-)
 delete mode 100644 tests/ui/traits/const-traits/const-closure-issue-125866-pass.rs

diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index e86a2f33b87b1..46b33a481214b 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -1062,7 +1062,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         binder: &ClosureBinder,
         capture_clause: CaptureBy,
         closure_id: NodeId,
-        constness: Const,
+        mut constness: Const,
         movability: Movability,
         decl: &FnDecl,
         body: &Expr,
@@ -1072,11 +1072,18 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let closure_def_id = self.local_def_id(closure_id);
         let (binder_clause, generic_params) = self.lower_closure_binder(binder);
 
+        if let Const::Yes(span) = constness {
+            if !self.is_in_const_context {
+                self.dcx().span_err(span, "cannot use `const` closures outside of const contexts");
+                constness = Const::No;
+            }
+        }
+
         let (body_id, closure_kind) = self.with_new_scopes(fn_decl_span, move |this| {
             let mut coroutine_kind = find_attr!(attrs, Coroutine(_) => hir::CoroutineKind::Coroutine(Movability::Movable));
 
             // FIXME(contracts): Support contracts on closures?
-            let body_id = this.lower_fn_body(decl, None, |this| {
+            let body_id = this.lower_fn_body(decl, None, constness, |this| {
                 this.coroutine_kind = coroutine_kind;
                 let e = this.lower_expr_mut(body);
                 coroutine_kind = this.coroutine_kind;
diff --git a/compiler/rustc_ast_lowering/src/item.rs b/compiler/rustc_ast_lowering/src/item.rs
index ed78b77a704f6..e2ac38caf2950 100644
--- a/compiler/rustc_ast_lowering/src/item.rs
+++ b/compiler/rustc_ast_lowering/src/item.rs
@@ -1,3 +1,5 @@
+use std::mem;
+
 use rustc_abi::ExternAbi;
 use rustc_ast::visit::AssocCtxt;
 use rustc_ast::*;
@@ -345,6 +347,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                         body.as_deref(),
                         attrs,
                         contract.as_deref(),
+                        header.constness,
                     );
 
                     let itctx = ImplTraitContext::Universal;
@@ -1024,6 +1027,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     Some(body),
                     attrs,
                     contract.as_deref(),
+                    sig.header.constness,
                 );
                 let (generics, sig) = self.lower_method_sig(
                     generics,
@@ -1217,6 +1221,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     body.as_deref(),
                     attrs,
                     contract.as_deref(),
+                    sig.header.constness,
                 );
                 let (generics, sig) = self.lower_method_sig(
                     generics,
@@ -1346,11 +1351,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
         f: impl FnOnce(&mut Self) -> (&'hir [hir::Param<'hir>], hir::Expr<'hir>),
     ) -> hir::BodyId {
         let prev_coroutine_kind = self.coroutine_kind.take();
+        let prev_is_in_const_context = mem::take(&mut self.is_in_const_context);
         let task_context = self.task_context.take();
         let (parameters, result) = f(self);
         let body_id = self.record_body(parameters, result);
         self.task_context = task_context;
         self.coroutine_kind = prev_coroutine_kind;
+        self.is_in_const_context = prev_is_in_const_context;
         body_id
     }
 
@@ -1369,9 +1376,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
         &mut self,
         decl: &FnDecl,
         contract: Option<&FnContract>,
+        constness: Const,
         body: impl FnOnce(&mut Self) -> hir::Expr<'hir>,
     ) -> hir::BodyId {
         self.lower_body(|this| {
+            if let Const::Yes(_) = constness {
+                this.is_in_const_context = true;
+            }
             let params =
                 this.arena.alloc_from_iter(decl.inputs.iter().map(|x| this.lower_param(x)));
 
@@ -1389,8 +1400,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
         decl: &FnDecl,
         body: &Block,
         contract: Option<&FnContract>,
+        constness: Const,
     ) -> hir::BodyId {
-        self.lower_fn_body(decl, contract, |this| this.lower_block_expr(body))
+        self.lower_fn_body(decl, contract, constness, |this| this.lower_block_expr(body))
     }
 
     pub(super) fn lower_const_body(&mut self, span: Span, expr: Option<&Expr>) -> hir::BodyId {
@@ -1398,7 +1410,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
             (
                 &[],
                 match expr {
-                    Some(expr) => this.lower_expr_mut(expr),
+                    Some(expr) => {
+                        this.is_in_const_context = true;
+                        this.lower_expr_mut(expr)
+                    }
                     None => this.expr_err(span, this.dcx().span_delayed_bug(span, "no block")),
                 },
             )
@@ -1417,12 +1432,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
         body: Option<&Block>,
         attrs: &'hir [hir::Attribute],
         contract: Option<&FnContract>,
+        constness: Const,
     ) -> hir::BodyId {
         let Some(body) = body else {
             // Functions without a body are an error, except if this is an intrinsic. For those we
             // create a fake body so that the entire rest of the compiler doesn't have to deal with
             // this as a special case.
-            return self.lower_fn_body(decl, contract, |this| {
+            return self.lower_fn_body(decl, contract, constness, |this| {
                 if find_attr!(attrs, RustcIntrinsic) || this.tcx.is_sdylib_interface_build() {
                     let span = this.lower_span(span);
                     let empty_block = hir::Block {
@@ -1447,7 +1463,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         };
         let Some(coroutine_kind) = coroutine_kind else {
             // Typical case: not a coroutine.
-            return self.lower_fn_body_block(decl, body, contract);
+            return self.lower_fn_body_block(decl, body, contract, constness);
         };
         // FIXME(contracts): Support contracts on async fn.
         self.lower_body(|this| {
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index c3525d1246705..e8092b540ec87 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -129,6 +129,7 @@ struct LoweringContext<'a, 'hir> {
     loop_scope: Option<HirId>,
     is_in_loop_condition: bool,
     is_in_dyn_type: bool,
+    is_in_const_context: bool,
 
     current_hir_id_owner: hir::OwnerId,
     item_local_id_counter: hir::ItemLocalId,
@@ -190,6 +191,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             loop_scope: None,
             is_in_loop_condition: false,
             is_in_dyn_type: false,
+            is_in_const_context: false,
             coroutine_kind: None,
             task_context: None,
             current_item: None,
diff --git a/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs b/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
index 7a44920bb729d..e13ee39631a3a 100644
--- a/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
+++ b/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
@@ -16,9 +16,9 @@ const fn create_array<const N: usize>(mut f: impl FnMut(usize) -> u32 + Copy) ->
 }
 
 fn main() {
-    let x = create_array(const |i| 2 * i as u32);
+    let x = const { create_array(const |i| 2 * i as u32) };
     assert_eq!(x, [0, 2, 4, 6, 8]);
 
-    let y = create_array(const |i| 2 * i as u32 + 1);
+    let y = const { create_array(const |i| 2 * i as u32 + 1) };
     assert_eq!(y, [1, 3, 5, 7, 9]);
 }
diff --git a/tests/ui/traits/const-traits/const-closure-issue-125866-pass.rs b/tests/ui/traits/const-traits/const-closure-issue-125866-pass.rs
deleted file mode 100644
index af7375172e674..0000000000000
--- a/tests/ui/traits/const-traits/const-closure-issue-125866-pass.rs
+++ /dev/null
@@ -1,25 +0,0 @@
-//@ check-pass
-
-#![allow(incomplete_features)]
-#![feature(const_closures, const_trait_impl)]
-
-const fn create_array<const N: usize>(mut f: impl [const] FnMut(usize) -> u32 + Copy) -> [u32; N] {
-    let mut array = [0; N];
-    let mut i = 0;
-    loop {
-        array[i] = f(i);
-        i += 1;
-        if i == N {
-            break;
-        }
-    }
-    array
-}
-
-fn main() {
-    let x = create_array(const |i| 2 * i as u32);
-    assert_eq!(x, [0, 2, 4, 6, 8]);
-
-    let y = create_array(const |i| 2 * i as u32 + 1);
-    assert_eq!(y, [1, 3, 5, 7, 9]);
-}
diff --git a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
index dab3f14161fac..bbe736b94b5ba 100644
--- a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
+++ b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
@@ -1,9 +1,8 @@
-error[E0277]: the trait bound `{closure@$DIR/const_closure-const_trait_impl-ice-113381.rs:15:6: 15:14}: [const] Fn()` is not satisfied
-  --> $DIR/const_closure-const_trait_impl-ice-113381.rs:15:5
+error: cannot use `const` closures outside of const contexts
+  --> $DIR/const_closure-const_trait_impl-ice-113381.rs:15:6
    |
 LL |     (const || (()).foo())();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^
+   |      ^^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/const-traits/gate.rs b/tests/ui/traits/const-traits/gate.rs
index 3f348c8413930..86b42099d2896 100644
--- a/tests/ui/traits/const-traits/gate.rs
+++ b/tests/ui/traits/const-traits/gate.rs
@@ -1,13 +1,13 @@
 // gate-test-const_closures
 
 fn main() {
-    (const || {})();
+    const { (const || {})() };
     //~^ ERROR: const closures are experimental
-    //~| ERROR: the trait bound `{closure@$DIR/gate.rs:4:6: 4:14}: [const] Fn()` is not satisfied
+    //~| ERROR: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: [const] Fn()` is not satisfied
 }
 
 macro_rules! e {
-    ($e:expr) => {}
+    ($e:expr) => {};
 }
 
 e!((const || {}));
diff --git a/tests/ui/traits/const-traits/gate.stderr b/tests/ui/traits/const-traits/gate.stderr
index 6bef2c511ce7d..b86217943d77b 100644
--- a/tests/ui/traits/const-traits/gate.stderr
+++ b/tests/ui/traits/const-traits/gate.stderr
@@ -1,8 +1,8 @@
 error[E0658]: const closures are experimental
-  --> $DIR/gate.rs:4:6
+  --> $DIR/gate.rs:4:14
    |
-LL |     (const || {})();
-   |      ^^^^^
+LL |     const { (const || {})() };
+   |              ^^^^^
    |
    = note: see issue #106003 <https://github.com/rust-lang/rust/issues/106003> for more information
    = help: add `#![feature(const_closures)]` to the crate attributes to enable
@@ -18,11 +18,11 @@ LL | e!((const || {}));
    = help: add `#![feature(const_closures)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0277]: the trait bound `{closure@$DIR/gate.rs:4:6: 4:14}: [const] Fn()` is not satisfied
-  --> $DIR/gate.rs:4:5
+error[E0277]: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: [const] Fn()` is not satisfied
+  --> $DIR/gate.rs:4:13
    |
-LL |     (const || {})();
-   |     ^^^^^^^^^^^^^^^
+LL |     const { (const || {})() };
+   |             ^^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
index de5bedf0ace76..a13fab3b21db2 100644
--- a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
+++ b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
@@ -13,5 +13,5 @@ fn main() {
     // #150052 deduplicate diagnostics for const trait supertraits
     // so we only get one error here
     (const || { (()).foo() })();
-    //~^ ERROR: }: [const] Fn()` is not satisfied
+    //~^ ERROR: cannot use `const` closures outside of const contexts
 }
diff --git a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
index efbedca1c7e7f..43c98ec7c661c 100644
--- a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
+++ b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
@@ -1,9 +1,8 @@
-error[E0277]: the trait bound `{closure@$DIR/non-const-op-const-closure-non-const-outer.rs:15:6: 15:14}: [const] Fn()` is not satisfied
-  --> $DIR/non-const-op-const-closure-non-const-outer.rs:15:5
+error: cannot use `const` closures outside of const contexts
+  --> $DIR/non-const-op-const-closure-non-const-outer.rs:15:6
    |
 LL |     (const || { (()).foo() })();
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |      ^^^^^
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0277`.

From e8a46117795f82f35e2f4087516a8743e28ba174 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Thu, 12 Mar 2026 08:38:41 +0000
Subject: [PATCH 03/13] Const closure's const context is the same as their
 parent

---
 compiler/rustc_middle/src/hir/map.rs                   | 10 ++++++----
 tests/ui/traits/const-traits/call-const-closure.rs     |  3 +--
 tests/ui/traits/const-traits/call-const-closure.stderr |  2 +-
 tests/ui/traits/const-traits/call.rs                   |  2 +-
 tests/ui/traits/const-traits/call.stderr               |  2 +-
 tests/ui/traits/const-traits/gate.rs                   |  2 +-
 tests/ui/traits/const-traits/gate.stderr               |  2 +-
 7 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/compiler/rustc_middle/src/hir/map.rs b/compiler/rustc_middle/src/hir/map.rs
index cf1b863f754c8..fc2a7fbd4fa9c 100644
--- a/compiler/rustc_middle/src/hir/map.rs
+++ b/compiler/rustc_middle/src/hir/map.rs
@@ -310,16 +310,18 @@ impl<'tcx> TyCtxt<'tcx> {
     /// This should only be used for determining the context of a body, a return
     /// value of `Some` does not always suggest that the owner of the body is `const`,
     /// just that it has to be checked as if it were.
-    pub fn hir_body_const_context(self, def_id: LocalDefId) -> Option<ConstContext> {
-        let def_id = def_id.into();
+    pub fn hir_body_const_context(self, local_def_id: LocalDefId) -> Option<ConstContext> {
+        let def_id = local_def_id.into();
         let ccx = match self.hir_body_owner_kind(def_id) {
             BodyOwnerKind::Const { inline } => ConstContext::Const { inline },
             BodyOwnerKind::Static(mutability) => ConstContext::Static(mutability),
 
             BodyOwnerKind::Fn if self.is_constructor(def_id) => return None,
-            BodyOwnerKind::Fn | BodyOwnerKind::Closure if self.is_const_fn(def_id) => {
-                ConstContext::ConstFn
+            // Const closures use their parent's const context
+            BodyOwnerKind::Closure if self.is_const_fn(def_id) => {
+                return self.hir_body_const_context(self.local_parent(local_def_id));
             }
+            BodyOwnerKind::Fn if self.is_const_fn(def_id) => ConstContext::ConstFn,
             BodyOwnerKind::Fn | BodyOwnerKind::Closure | BodyOwnerKind::GlobalAsm => return None,
         };
 
diff --git a/tests/ui/traits/const-traits/call-const-closure.rs b/tests/ui/traits/const-traits/call-const-closure.rs
index c4293579aea8e..a26f7be1148dd 100644
--- a/tests/ui/traits/const-traits/call-const-closure.rs
+++ b/tests/ui/traits/const-traits/call-const-closure.rs
@@ -14,8 +14,7 @@ impl Bar for () {
 
 const FOO: () = {
     (const || ().foo())();
-    //~^ ERROR the trait bound `(): [const] Bar` is not satisfied
-    // FIXME(const_trait_impl): The constness environment for const closures is wrong.
+    //~^ ERROR the trait bound `(): const Bar` is not satisfied
 };
 
 fn main() {}
diff --git a/tests/ui/traits/const-traits/call-const-closure.stderr b/tests/ui/traits/const-traits/call-const-closure.stderr
index 9a851a97f186a..16b936d58aaf6 100644
--- a/tests/ui/traits/const-traits/call-const-closure.stderr
+++ b/tests/ui/traits/const-traits/call-const-closure.stderr
@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `(): [const] Bar` is not satisfied
+error[E0277]: the trait bound `(): const Bar` is not satisfied
   --> $DIR/call-const-closure.rs:16:18
    |
 LL |     (const || ().foo())();
diff --git a/tests/ui/traits/const-traits/call.rs b/tests/ui/traits/const-traits/call.rs
index 360c08e1b7fe9..e93ea4ccbd708 100644
--- a/tests/ui/traits/const-traits/call.rs
+++ b/tests/ui/traits/const-traits/call.rs
@@ -5,7 +5,7 @@
 
 const _: () = {
     assert!((const || true)());
-    //~^ ERROR }: [const] Fn()` is not satisfied
+    //~^ ERROR }: const Fn()` is not satisfied
 };
 
 fn main() {}
diff --git a/tests/ui/traits/const-traits/call.stderr b/tests/ui/traits/const-traits/call.stderr
index 8e32cab6dfcfb..3503938327a9f 100644
--- a/tests/ui/traits/const-traits/call.stderr
+++ b/tests/ui/traits/const-traits/call.stderr
@@ -1,4 +1,4 @@
-error[E0277]: the trait bound `{closure@$DIR/call.rs:7:14: 7:22}: [const] Fn()` is not satisfied
+error[E0277]: the trait bound `{closure@$DIR/call.rs:7:14: 7:22}: const Fn()` is not satisfied
   --> $DIR/call.rs:7:13
    |
 LL |     assert!((const || true)());
diff --git a/tests/ui/traits/const-traits/gate.rs b/tests/ui/traits/const-traits/gate.rs
index 86b42099d2896..0821a45edb5e5 100644
--- a/tests/ui/traits/const-traits/gate.rs
+++ b/tests/ui/traits/const-traits/gate.rs
@@ -3,7 +3,7 @@
 fn main() {
     const { (const || {})() };
     //~^ ERROR: const closures are experimental
-    //~| ERROR: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: [const] Fn()` is not satisfied
+    //~| ERROR: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: const Fn()` is not satisfied
 }
 
 macro_rules! e {
diff --git a/tests/ui/traits/const-traits/gate.stderr b/tests/ui/traits/const-traits/gate.stderr
index b86217943d77b..af5905524437d 100644
--- a/tests/ui/traits/const-traits/gate.stderr
+++ b/tests/ui/traits/const-traits/gate.stderr
@@ -18,7 +18,7 @@ LL | e!((const || {}));
    = help: add `#![feature(const_closures)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0277]: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: [const] Fn()` is not satisfied
+error[E0277]: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: const Fn()` is not satisfied
   --> $DIR/gate.rs:4:13
    |
 LL |     const { (const || {})() };

From 8459d6bf3a6ba46368c6649f1cc7d9ba332c9e9c Mon Sep 17 00:00:00 2001
From: Sinan Nalkaya <sardok@gmail.com>
Date: Thu, 12 Mar 2026 13:14:40 +0100
Subject: [PATCH 04/13] Fix std doctest build for SGX target.

---
 library/std/src/os/fd/raw.rs              | 2 +-
 library/std/src/sys/net/connection/sgx.rs | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/library/std/src/os/fd/raw.rs b/library/std/src/os/fd/raw.rs
index 39e374174646c..0d96958b6cca1 100644
--- a/library/std/src/os/fd/raw.rs
+++ b/library/std/src/os/fd/raw.rs
@@ -16,7 +16,7 @@ use crate::io;
 use crate::os::hermit::io::OwnedFd;
 #[cfg(all(not(target_os = "hermit"), not(target_os = "motor")))]
 use crate::os::raw;
-#[cfg(all(doc, not(target_arch = "wasm32")))]
+#[cfg(all(doc, not(any(target_arch = "wasm32", target_env = "sgx"))))]
 use crate::os::unix::io::AsFd;
 #[cfg(unix)]
 use crate::os::unix::io::OwnedFd;
diff --git a/library/std/src/sys/net/connection/sgx.rs b/library/std/src/sys/net/connection/sgx.rs
index 8c9c17d3f1714..6a625664494b5 100644
--- a/library/std/src/sys/net/connection/sgx.rs
+++ b/library/std/src/sys/net/connection/sgx.rs
@@ -68,8 +68,8 @@ impl fmt::Debug for TcpStream {
 ///
 /// SGX doesn't support DNS resolution but rather accepts hostnames in
 /// the same place as socket addresses. So, to make e.g.
-/// ```rust
-/// TcpStream::connect("example.com:80")`
+/// ```rust,ignore (incomplete example)
+/// TcpStream::connect("example.com:80")
 /// ```
 /// work, the DNS lookup returns a special error (`NonIpSockAddr`) instead,
 /// which contains the hostname being looked up. When `.to_socket_addrs()`

From 1f44a11518096de272003492a8fe2c300dbf2989 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Tue, 3 Mar 2026 11:34:00 +0100
Subject: [PATCH 05/13] Replace `visit_waiters` with `abstracted_waiters_of`

---
 compiler/rustc_middle/src/query/job.rs |  10 +-
 compiler/rustc_query_impl/src/job.rs   | 165 ++++++++++++++-----------
 2 files changed, 101 insertions(+), 74 deletions(-)

diff --git a/compiler/rustc_middle/src/query/job.rs b/compiler/rustc_middle/src/query/job.rs
index 2747935942b55..b2e5649106ce9 100644
--- a/compiler/rustc_middle/src/query/job.rs
+++ b/compiler/rustc_middle/src/query/job.rs
@@ -65,7 +65,7 @@ impl<'tcx> QueryJob<'tcx> {
 
 #[derive(Debug)]
 pub struct QueryWaiter<'tcx> {
-    pub query: Option<QueryJobId>,
+    pub parent: Option<QueryJobId>,
     pub condvar: Condvar,
     pub span: Span,
     pub cycle: Mutex<Option<CycleError<'tcx>>>,
@@ -94,8 +94,12 @@ impl<'tcx> QueryLatch<'tcx> {
             return Ok(()); // already complete
         };
 
-        let waiter =
-            Arc::new(QueryWaiter { query, span, cycle: Mutex::new(None), condvar: Condvar::new() });
+        let waiter = Arc::new(QueryWaiter {
+            parent: query,
+            span,
+            cycle: Mutex::new(None),
+            condvar: Condvar::new(),
+        });
 
         // We push the waiter on to the `waiters` list. It can be accessed inside
         // the `wait` call below, by 1) the `set` method or 2) by deadlock detection.
diff --git a/compiler/rustc_query_impl/src/job.rs b/compiler/rustc_query_impl/src/job.rs
index ae32ad01b1578..900fca23c9524 100644
--- a/compiler/rustc_query_impl/src/job.rs
+++ b/compiler/rustc_query_impl/src/job.rs
@@ -111,38 +111,44 @@ pub(crate) fn find_dep_kind_root<'tcx>(
     last_layout
 }
 
-/// A resumable waiter of a query. The usize is the index into waiters in the query's latch
-type Waiter = (QueryJobId, usize);
-
-/// Visits all the non-resumable and resumable waiters of a query.
-/// Only waiters in a query are visited.
-/// `visit` is called for every waiter and is passed a query waiting on `query`
-/// and a span indicating the reason the query waited on `query`.
-/// If `visit` returns `Break`, this function also returns `Break`,
-/// and if all `visit` calls returns `Continue` it also returns `Continue`.
-/// For visits of non-resumable waiters it returns the return value of `visit`.
-/// For visits of resumable waiters it returns information required to resume that waiter.
-fn visit_waiters<'tcx>(
-    job_map: &QueryJobMap<'tcx>,
-    query: QueryJobId,
-    mut visit: impl FnMut(Span, QueryJobId) -> ControlFlow<Option<Waiter>>,
-) -> ControlFlow<Option<Waiter>> {
-    // Visit the parent query which is a non-resumable waiter since it's on the same stack
-    if let Some(parent) = job_map.parent_of(query) {
-        visit(job_map.span_of(query), parent)?;
-    }
+/// The locaton of a resumable waiter. The usize is the index into waiters in the query's latch.
+/// We'll use this to remove the waiter using `QueryLatch::extract_waiter` if we're waking it up.
+type ResumableWaiterLocation = (QueryJobId, usize);
+
+/// This abstracts over non-resumable waiters which are found in `QueryJob`'s `parent` field
+/// and resumable waiters are in `latch` field.
+struct AbstractedWaiter {
+    /// The span corresponding to the reason for why we're waiting on this query.
+    span: Span,
+    /// The query which we are waiting from, if none the waiter is from a compiler root.
+    parent: Option<QueryJobId>,
+    resumable: Option<ResumableWaiterLocation>,
+}
+
+/// Returns all the non-resumable and resumable waiters of a query.
+/// This is used so we can uniformly loop over both non-resumable and resumable waiters.
+fn abstracted_waiters_of(job_map: &QueryJobMap<'_>, query: QueryJobId) -> Vec<AbstractedWaiter> {
+    let mut result = Vec::new();
 
-    // Visit the explicit waiters which use condvars and are resumable
+    // Add the parent which is a non-resumable waiter since it's on the same stack
+    result.push(AbstractedWaiter {
+        span: job_map.span_of(query),
+        parent: job_map.parent_of(query),
+        resumable: None,
+    });
+
+    // Add the explicit waiters which use condvars and are resumable
     if let Some(latch) = job_map.latch_of(query) {
         for (i, waiter) in latch.waiters.lock().as_ref().unwrap().iter().enumerate() {
-            if let Some(waiter_query) = waiter.query {
-                // Return a value which indicates that this waiter can be resumed
-                visit(waiter.span, waiter_query).map_break(|_| Some((query, i)))?;
-            }
+            result.push(AbstractedWaiter {
+                span: waiter.span,
+                parent: waiter.parent,
+                resumable: Some((query, i)),
+            });
         }
     }
 
-    ControlFlow::Continue(())
+    result
 }
 
 /// Look for query cycles by doing a depth first search starting at `query`.
@@ -155,13 +161,13 @@ fn cycle_check<'tcx>(
     span: Span,
     stack: &mut Vec<(Span, QueryJobId)>,
     visited: &mut FxHashSet<QueryJobId>,
-) -> ControlFlow<Option<Waiter>> {
+) -> ControlFlow<Option<ResumableWaiterLocation>> {
     if !visited.insert(query) {
-        return if let Some(p) = stack.iter().position(|q| q.1 == query) {
+        return if let Some(pos) = stack.iter().position(|q| q.1 == query) {
             // We detected a query cycle, fix up the initial span and return Some
 
             // Remove previous stack entries
-            stack.drain(0..p);
+            stack.drain(0..pos);
             // Replace the span for the first query with the cycle cause
             stack[0].0 = span;
             ControlFlow::Break(None)
@@ -174,16 +180,23 @@ fn cycle_check<'tcx>(
     stack.push((span, query));
 
     // Visit all the waiters
-    let r = visit_waiters(job_map, query, |span, successor| {
-        cycle_check(job_map, successor, span, stack, visited)
-    });
-
-    // Remove the entry in our stack if we didn't find a cycle
-    if r.is_continue() {
-        stack.pop();
+    for abstracted_waiter in abstracted_waiters_of(job_map, query) {
+        let Some(parent) = abstracted_waiter.parent else {
+            // Skip waiters which are not queries
+            continue;
+        };
+        if let ControlFlow::Break(maybe_resumable) =
+            cycle_check(job_map, parent, abstracted_waiter.span, stack, visited)
+        {
+            // Return the resumable waiter in `waiter.resumable` if present
+            return ControlFlow::Break(abstracted_waiter.resumable.or(maybe_resumable));
+        }
     }
 
-    r
+    // Remove the entry in our stack since we didn't find a cycle
+    stack.pop();
+
+    ControlFlow::Continue(())
 }
 
 /// Finds out if there's a path to the compiler root (aka. code which isn't in a query)
@@ -193,18 +206,26 @@ fn connected_to_root<'tcx>(
     job_map: &QueryJobMap<'tcx>,
     query: QueryJobId,
     visited: &mut FxHashSet<QueryJobId>,
-) -> ControlFlow<Option<Waiter>> {
+) -> bool {
     // We already visited this or we're deliberately ignoring it
     if !visited.insert(query) {
-        return ControlFlow::Continue(());
+        return false;
     }
 
-    // This query is connected to the root (it has no query parent), return true
-    if job_map.parent_of(query).is_none() {
-        return ControlFlow::Break(None);
+    // Visit all the waiters
+    for abstracted_waiter in abstracted_waiters_of(job_map, query) {
+        match abstracted_waiter.parent {
+            // This query is connected to the root
+            None => return true,
+            Some(parent) => {
+                if connected_to_root(job_map, parent, visited) {
+                    return true;
+                }
+            }
+        }
     }
 
-    visit_waiters(job_map, query, |_, successor| connected_to_root(job_map, successor, visited))
+    false
 }
 
 /// Looks for query cycles starting from the last query in `jobs`.
@@ -220,7 +241,7 @@ fn remove_cycle<'tcx>(
     let mut visited = FxHashSet::default();
     let mut stack = Vec::new();
     // Look for a cycle starting with the last query in `jobs`
-    if let ControlFlow::Break(waiter) =
+    if let ControlFlow::Break(resumable) =
         cycle_check(job_map, jobs.pop().unwrap(), DUMMY_SP, &mut stack, &mut visited)
     {
         // The stack is a vector of pairs of spans and queries; reverse it so that
@@ -242,7 +263,7 @@ fn remove_cycle<'tcx>(
 
         struct EntryPoint {
             query_in_cycle: QueryJobId,
-            waiter: Option<(Span, QueryJobId)>,
+            query_waiting_on_cycle: Option<(Span, QueryJobId)>,
         }
 
         // Find the queries in the cycle which are
@@ -250,36 +271,36 @@ fn remove_cycle<'tcx>(
         let entry_points = stack
             .iter()
             .filter_map(|&(_, query_in_cycle)| {
-                if job_map.parent_of(query_in_cycle).is_none() {
-                    // This query is connected to the root (it has no query parent)
-                    Some(EntryPoint { query_in_cycle, waiter: None })
-                } else {
-                    let mut waiter_on_cycle = None;
-                    // Find a direct waiter who leads to the root
-                    let _ = visit_waiters(job_map, query_in_cycle, |span, waiter| {
-                        // Mark all the other queries in the cycle as already visited
-                        let mut visited = FxHashSet::from_iter(stack.iter().map(|q| q.1));
-
-                        if connected_to_root(job_map, waiter, &mut visited).is_break() {
-                            waiter_on_cycle = Some((span, waiter));
-                            ControlFlow::Break(None)
-                        } else {
-                            ControlFlow::Continue(())
-                        }
-                    });
-
-                    waiter_on_cycle.map(|waiter_on_cycle| EntryPoint {
-                        query_in_cycle,
-                        waiter: Some(waiter_on_cycle),
-                    })
+                let mut entrypoint = false;
+                let mut query_waiting_on_cycle = None;
+
+                // Find a direct waiter who leads to the root
+                for abstracted_waiter in abstracted_waiters_of(job_map, query_in_cycle) {
+                    let Some(parent) = abstracted_waiter.parent else {
+                        // The query in the cycle is directly connected to root.
+                        entrypoint = true;
+                        continue;
+                    };
+
+                    // Mark all the other queries in the cycle as already visited,
+                    // so paths to the root through the cycle itself won't count.
+                    let mut visited = FxHashSet::from_iter(stack.iter().map(|q| q.1));
+
+                    if connected_to_root(job_map, parent, &mut visited) {
+                        query_waiting_on_cycle = Some((abstracted_waiter.span, parent));
+                        entrypoint = true;
+                        break;
+                    }
                 }
+
+                entrypoint.then_some(EntryPoint { query_in_cycle, query_waiting_on_cycle })
             })
             .collect::<Vec<EntryPoint>>();
 
         // Pick an entry point, preferring ones with waiters
         let entry_point = entry_points
             .iter()
-            .find(|entry_point| entry_point.waiter.is_some())
+            .find(|entry_point| entry_point.query_waiting_on_cycle.is_some())
             .unwrap_or(&entry_points[0]);
 
         // Shift the stack so that our entry point is first
@@ -289,7 +310,9 @@ fn remove_cycle<'tcx>(
             stack.rotate_left(pos);
         }
 
-        let usage = entry_point.waiter.map(|(span, job)| (span, job_map.frame_of(job).clone()));
+        let usage = entry_point
+            .query_waiting_on_cycle
+            .map(|(span, job)| (span, job_map.frame_of(job).clone()));
 
         // Create the cycle error
         let error = CycleError {
@@ -300,9 +323,9 @@ fn remove_cycle<'tcx>(
                 .collect(),
         };
 
-        // We unwrap `waiter` here since there must always be one
+        // We unwrap `resumable` here since there must always be one
         // edge which is resumable / waited using a query latch
-        let (waitee_query, waiter_idx) = waiter.unwrap();
+        let (waitee_query, waiter_idx) = resumable.unwrap();
 
         // Extract the waiter we want to resume
         let waiter = job_map.latch_of(waitee_query).unwrap().extract_waiter(waiter_idx);

From 791f4f9315cdf85c5137c26070f2818d332d66b7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Thu, 12 Mar 2026 15:55:28 +0100
Subject: [PATCH 06/13] Remove `value_from_cycle_error` specialization for
 `type_of_opaque_hir_typeck`

---
 compiler/rustc_query_impl/src/from_cycle_error.rs | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/compiler/rustc_query_impl/src/from_cycle_error.rs b/compiler/rustc_query_impl/src/from_cycle_error.rs
index 6a3155c02949e..3cca35601feb3 100644
--- a/compiler/rustc_query_impl/src/from_cycle_error.rs
+++ b/compiler/rustc_query_impl/src/from_cycle_error.rs
@@ -26,11 +26,6 @@ pub(crate) fn specialize_query_vtables<'tcx>(vtables: &mut QueryVTables<'tcx>) {
         erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)))
     };
 
-    vtables.type_of_opaque_hir_typeck.value_from_cycle_error = |tcx, _, _, err| {
-        let guar = err.emit();
-        erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)))
-    };
-
     vtables.erase_and_anonymize_regions_ty.value_from_cycle_error = |tcx, _, _, err| {
         let guar = err.emit();
         erase_val(Ty::new_error(tcx, guar))

From cdbe2b35b55bb38ac503e0989e69cca9aa530ce5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Thu, 12 Mar 2026 16:35:50 +0100
Subject: [PATCH 07/13] Remove `value_from_cycle_error` specialization for
 `erase_and_anonymize_regions_ty`

---
 compiler/rustc_query_impl/src/from_cycle_error.rs | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/compiler/rustc_query_impl/src/from_cycle_error.rs b/compiler/rustc_query_impl/src/from_cycle_error.rs
index 3cca35601feb3..0cc3b2cf7eec7 100644
--- a/compiler/rustc_query_impl/src/from_cycle_error.rs
+++ b/compiler/rustc_query_impl/src/from_cycle_error.rs
@@ -26,11 +26,6 @@ pub(crate) fn specialize_query_vtables<'tcx>(vtables: &mut QueryVTables<'tcx>) {
         erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)))
     };
 
-    vtables.erase_and_anonymize_regions_ty.value_from_cycle_error = |tcx, _, _, err| {
-        let guar = err.emit();
-        erase_val(Ty::new_error(tcx, guar))
-    };
-
     vtables.fn_sig.value_from_cycle_error = |tcx, key, _, err| {
         let guar = err.delay_as_bug();
         erase_val(fn_sig(tcx, key, guar))

From fed57899b93d6e17b00bf00326d7b9aebdccc6e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= <john.kare.alsaker@gmail.com>
Date: Thu, 12 Mar 2026 17:02:49 +0100
Subject: [PATCH 08/13] Remove `value_from_cycle_error` specialization for
 `type_of`

---
 .../rustc_query_impl/src/from_cycle_error.rs  |  5 --
 tests/incremental/const-generic-type-cycle.rs |  2 -
 tests/ui/consts/issue-103790.rs               |  1 -
 tests/ui/consts/issue-103790.stderr           | 14 +----
 .../ui/delegation/unsupported.current.stderr  | 19 +++---
 tests/ui/delegation/unsupported.next.stderr   | 15 +----
 tests/ui/delegation/unsupported.rs            |  1 -
 ...ompatability-via-leakage-cycle.next.stderr | 62 +------------------
 tests/ui/issues/issue-34373.rs                |  1 -
 tests/ui/issues/issue-34373.stderr            | 16 +----
 ...ce-hir-wf-check-anon-const-issue-122199.rs |  1 -
 ...ir-wf-check-anon-const-issue-122199.stderr | 10 +--
 ...ce-hir-wf-check-anon-const-issue-122989.rs |  2 -
 ...ir-wf-check-anon-const-issue-122989.stderr | 22 +------
 14 files changed, 20 insertions(+), 151 deletions(-)

diff --git a/compiler/rustc_query_impl/src/from_cycle_error.rs b/compiler/rustc_query_impl/src/from_cycle_error.rs
index 0cc3b2cf7eec7..8214f80cda410 100644
--- a/compiler/rustc_query_impl/src/from_cycle_error.rs
+++ b/compiler/rustc_query_impl/src/from_cycle_error.rs
@@ -21,11 +21,6 @@ use rustc_span::{ErrorGuaranteed, Span};
 use crate::job::report_cycle;
 
 pub(crate) fn specialize_query_vtables<'tcx>(vtables: &mut QueryVTables<'tcx>) {
-    vtables.type_of.value_from_cycle_error = |tcx, _, _, err| {
-        let guar = err.emit();
-        erase_val(ty::EarlyBinder::bind(Ty::new_error(tcx, guar)))
-    };
-
     vtables.fn_sig.value_from_cycle_error = |tcx, key, _, err| {
         let guar = err.delay_as_bug();
         erase_val(fn_sig(tcx, key, guar))
diff --git a/tests/incremental/const-generic-type-cycle.rs b/tests/incremental/const-generic-type-cycle.rs
index 5bcbc1d5dafef..85b8092787e2c 100644
--- a/tests/incremental/const-generic-type-cycle.rs
+++ b/tests/incremental/const-generic-type-cycle.rs
@@ -13,7 +13,5 @@ trait Bar<const N: usize> {}
 #[cfg(cfail)]
 trait Bar<const N: dyn BB> {}
 //[cfail]~^ ERROR cycle detected when computing type of `Bar::N`
-//[cfail]~| ERROR cycle detected when computing type of `Bar::N`
-//[cfail]~| ERROR `(dyn Bar<{ 2 + 1 }> + 'static)` is forbidden as the type of a const generic parameter
 
 trait BB = Bar<{ 2 + 1 }>;
diff --git a/tests/ui/consts/issue-103790.rs b/tests/ui/consts/issue-103790.rs
index 869a43e4018b3..a85833a565372 100644
--- a/tests/ui/consts/issue-103790.rs
+++ b/tests/ui/consts/issue-103790.rs
@@ -5,6 +5,5 @@ struct S<const S: (), const S: S = { S }>;
 //~^ ERROR the name `S` is already used for a generic parameter in this item's generic parameters
 //~| ERROR missing generics for struct `S`
 //~| ERROR cycle detected when computing type of `S::S`
-//~| ERROR `()` is forbidden as the type of a const generic parameter
 
 fn main() {}
diff --git a/tests/ui/consts/issue-103790.stderr b/tests/ui/consts/issue-103790.stderr
index adfac02bd0ceb..e442c64e70ce1 100644
--- a/tests/ui/consts/issue-103790.stderr
+++ b/tests/ui/consts/issue-103790.stderr
@@ -36,19 +36,7 @@ LL | struct S<const S: (), const S: S = { S }>;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: `()` is forbidden as the type of a const generic parameter
-  --> $DIR/issue-103790.rs:4:19
-   |
-LL | struct S<const S: (), const S: S = { S }>;
-   |                   ^^
-   |
-   = note: the only supported types are integers, `bool`, and `char`
-help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
-   |
-LL + #![feature(adt_const_params)]
-   |
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0107, E0391, E0403.
 For more information about an error, try `rustc --explain E0107`.
diff --git a/tests/ui/delegation/unsupported.current.stderr b/tests/ui/delegation/unsupported.current.stderr
index 9bc2eec068fef..657f990271734 100644
--- a/tests/ui/delegation/unsupported.current.stderr
+++ b/tests/ui/delegation/unsupported.current.stderr
@@ -29,18 +29,13 @@ note: ...which requires comparing an impl and trait method signature, inferring
 LL |         reuse ToReuse::opaque_ret;
    |                        ^^^^^^^^^^
    = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:32:5: 32:25>::opaque_ret::{anon_assoc#0}`, completing the cycle
-   = note: cycle used when checking effective visibilities
-   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
-
-error[E0283]: type annotations needed
-  --> $DIR/unsupported.rs:54:18
-   |
-LL |     reuse Trait::foo;
-   |                  ^^^ cannot infer type
+note: cycle used when checking assoc item `opaque::<impl at $DIR/unsupported.rs:32:5: 32:25>::opaque_ret` is compatible with trait definition
+  --> $DIR/unsupported.rs:33:24
    |
-   = note: cannot satisfy `_: effects::Trait`
+LL |         reuse ToReuse::opaque_ret;
+   |                        ^^^^^^^^^^
+   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0283, E0391.
-For more information about an error, try `rustc --explain E0283`.
+For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/delegation/unsupported.next.stderr b/tests/ui/delegation/unsupported.next.stderr
index 08bc49513bad5..90b17752cd8b1 100644
--- a/tests/ui/delegation/unsupported.next.stderr
+++ b/tests/ui/delegation/unsupported.next.stderr
@@ -25,18 +25,9 @@ note: ...which requires comparing an impl and trait method signature, inferring
 LL |         reuse ToReuse::opaque_ret;
    |                        ^^^^^^^^^^
    = note: ...which again requires computing type of `opaque::<impl at $DIR/unsupported.rs:32:5: 32:25>::opaque_ret::{anon_assoc#0}`, completing the cycle
-   = note: cycle used when checking effective visibilities
+   = note: cycle used when computing implied outlives bounds for `<u16 as opaque::ToReuse>::opaque_ret::{anon_assoc#0}` (hack disabled = false)
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error[E0283]: type annotations needed
-  --> $DIR/unsupported.rs:54:18
-   |
-LL |     reuse Trait::foo;
-   |                  ^^^ cannot infer type
-   |
-   = note: cannot satisfy `_: effects::Trait`
-
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0283, E0391.
-For more information about an error, try `rustc --explain E0283`.
+For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/delegation/unsupported.rs b/tests/ui/delegation/unsupported.rs
index 1681888e34ea6..adb798aab71d0 100644
--- a/tests/ui/delegation/unsupported.rs
+++ b/tests/ui/delegation/unsupported.rs
@@ -52,7 +52,6 @@ mod effects {
     }
 
     reuse Trait::foo;
-    //~^ ERROR type annotations needed
 }
 
 fn main() {}
diff --git a/tests/ui/impl-trait/in-trait/method-compatability-via-leakage-cycle.next.stderr b/tests/ui/impl-trait/in-trait/method-compatability-via-leakage-cycle.next.stderr
index f0a20367a4a1a..87640517ddb20 100644
--- a/tests/ui/impl-trait/in-trait/method-compatability-via-leakage-cycle.next.stderr
+++ b/tests/ui/impl-trait/in-trait/method-compatability-via-leakage-cycle.next.stderr
@@ -57,66 +57,6 @@ LL |     fn foo(b: bool) -> impl Sized {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error[E0391]: cycle detected when computing type of `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo::{anon_assoc#0}`
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:24
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |                        ^^^^^^^^^^
-   |
-note: ...which requires comparing an impl and trait method signature, inferring any hidden `impl Trait` types in the process...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires computing type of `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo::{opaque#0}`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:24
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |                        ^^^^^^^^^^
-note: ...which requires computing type of opaque `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo::{opaque#0}`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:24
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |                        ^^^^^^^^^^
-note: ...which requires borrow-checking `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires promoting constants in MIR for `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires checking if `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo` contains FFI-unwind calls...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires building MIR for `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires match-checking `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires type-checking `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo`...
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which again requires computing type of `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo::{anon_assoc#0}`, completing the cycle
-note: cycle used when checking assoc item `<impl at $DIR/method-compatability-via-leakage-cycle.rs:17:1: 17:19>::foo` is compatible with trait definition
-  --> $DIR/method-compatability-via-leakage-cycle.rs:21:5
-   |
-LL |     fn foo(b: bool) -> impl Sized {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/issues/issue-34373.rs b/tests/ui/issues/issue-34373.rs
index 765bfc20a4517..a9bd79f6830b8 100644
--- a/tests/ui/issues/issue-34373.rs
+++ b/tests/ui/issues/issue-34373.rs
@@ -6,7 +6,6 @@ trait Trait<T> {
 
 pub struct Foo<T = Box<dyn Trait<DefaultFoo>>>;
 //~^ ERROR cycle detected when computing type of `Foo::T`
-//~| ERROR type parameter `T` is never used
 type DefaultFoo = Foo;
 
 fn main() {
diff --git a/tests/ui/issues/issue-34373.stderr b/tests/ui/issues/issue-34373.stderr
index 6d68de8fb3b8a..995f2f4022b62 100644
--- a/tests/ui/issues/issue-34373.stderr
+++ b/tests/ui/issues/issue-34373.stderr
@@ -5,7 +5,7 @@ LL | pub struct Foo<T = Box<dyn Trait<DefaultFoo>>>;
    |                                  ^^^^^^^^^^
    |
 note: ...which requires expanding type alias `DefaultFoo`...
-  --> $DIR/issue-34373.rs:10:19
+  --> $DIR/issue-34373.rs:9:19
    |
 LL | type DefaultFoo = Foo;
    |                   ^^^
@@ -17,16 +17,6 @@ LL | pub struct Foo<T = Box<dyn Trait<DefaultFoo>>>;
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error[E0392]: type parameter `T` is never used
-  --> $DIR/issue-34373.rs:7:16
-   |
-LL | pub struct Foo<T = Box<dyn Trait<DefaultFoo>>>;
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unused type parameter
-   |
-   = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
-   = help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0391, E0392.
-For more information about an error, try `rustc --explain E0391`.
+For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
index 072a699a6b5b9..732a5c334e50d 100644
--- a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
@@ -4,7 +4,6 @@ trait Trait<const N: dyn Trait = bar> {
     fn fnc<const N: dyn Trait = u32>(&self) -> dyn Trait {
         //~^ ERROR the name `N` is already used for a generic parameter in this item's generic parameters
         //~| ERROR expected value, found builtin type `u32`
-        //~| ERROR defaults for generic parameters are not allowed here
         bar
         //~^ ERROR cannot find value `bar` in this scope
     }
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
index 47f3e83fae21a..ce567b9043f06 100644
--- a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
@@ -20,7 +20,7 @@ LL |     fn fnc<const N: dyn Trait = u32>(&self) -> dyn Trait {
    |                                 ^^^ not a value
 
 error[E0425]: cannot find value `bar` in this scope
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:8:9
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:7:9
    |
 LL |         bar
    |         ^^^ not found in this scope
@@ -39,13 +39,7 @@ LL | trait Trait<const N: dyn Trait = bar> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: defaults for generic parameters are not allowed here
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:4:12
-   |
-LL |     fn fnc<const N: dyn Trait = u32>(&self) -> dyn Trait {
-   |            ^^^^^^^^^^^^^^^^^^^^^^^^
-
-error: aborting due to 6 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0391, E0403, E0423, E0425.
 For more information about an error, try `rustc --explain E0391`.
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.rs b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.rs
index 13d7a800c51fd..f2b9f037ea5f3 100644
--- a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.rs
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.rs
@@ -4,13 +4,11 @@ trait Foo<const N: Bar<2>> {
     //~^ WARN trait objects without an explicit `dyn` are deprecated
     //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
     //~| ERROR cycle detected when computing type of `Foo::N`
-    //~| ERROR `(dyn Bar<2> + 'static)` is forbidden as the type of a const generic parameter
     fn func() {}
 }
 
 trait Bar<const M: Foo<2>> {}
 //~^ WARN trait objects without an explicit `dyn` are deprecated
 //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
-//~| ERROR `(dyn Foo<2> + 'static)` is forbidden as the type of a const generic parameter
 
 fn main() {}
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.stderr b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.stderr
index f9a855d3b93b7..4024f57af4ffd 100644
--- a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.stderr
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.stderr
@@ -13,7 +13,7 @@ LL | trait Foo<const N: dyn Bar<2>> {
    |                    +++
 
 warning: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:20
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:10:20
    |
 LL | trait Bar<const M: Foo<2>> {}
    |                    ^^^^^^
@@ -32,7 +32,7 @@ LL | trait Foo<const N: Bar<2>> {
    |           ^^^^^^^^^^^^^^^
    |
 note: ...which requires computing type of `Bar::M`...
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:11
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:10:11
    |
 LL | trait Bar<const M: Foo<2>> {}
    |           ^^^^^^^^^^^^^^^
@@ -44,22 +44,6 @@ LL | trait Foo<const N: Bar<2>> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: `(dyn Bar<2> + 'static)` is forbidden as the type of a const generic parameter
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:3:20
-   |
-LL | trait Foo<const N: Bar<2>> {
-   |                    ^^^^^^
-   |
-   = note: the only supported types are integers, `bool`, and `char`
-
-error: `(dyn Foo<2> + 'static)` is forbidden as the type of a const generic parameter
-  --> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:20
-   |
-LL | trait Bar<const M: Foo<2>> {}
-   |                    ^^^^^^
-   |
-   = note: the only supported types are integers, `bool`, and `char`
-
-error: aborting due to 3 previous errors; 2 warnings emitted
+error: aborting due to 1 previous error; 2 warnings emitted
 
 For more information about this error, try `rustc --explain E0391`.

From 1867653c81ac31900ae623e3970dba8f833bf870 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Wed, 11 Mar 2026 07:37:29 +0000
Subject: [PATCH 09/13] Allow calling const closures in const items

---
 .../src/collect/predicates_of.rs              |  3 +++
 .../src/ty/context/impl_interner.rs           |  5 +++++
 compiler/rustc_middle/src/ty/mod.rs           |  6 +-----
 .../src/solve/assembly/structural_traits.rs   | 21 ++++++++++++++-----
 .../src/solve/effect_goals.rs                 |  3 ++-
 compiler/rustc_type_ir/src/interner.rs        |  1 +
 tests/ui/traits/const-traits/call.rs          |  3 +--
 tests/ui/traits/const-traits/call.stderr      |  9 --------
 8 files changed, 29 insertions(+), 22 deletions(-)
 delete mode 100644 tests/ui/traits/const-traits/call.stderr

diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
index e16fa5492979f..98999232a7435 100644
--- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
@@ -1069,6 +1069,9 @@ pub(super) fn const_conditions<'tcx>(
         },
         // N.B. Tuple ctors are unconditionally constant.
         Node::Ctor(hir::VariantData::Tuple { .. }) => return Default::default(),
+        Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_), .. }) => {
+            (hir::Generics::empty(), None, tcx.is_conditionally_const(tcx.local_parent(def_id)))
+        }
         _ => bug!("const_conditions called on wrong item: {def_id:?}"),
     };
 
diff --git a/compiler/rustc_middle/src/ty/context/impl_interner.rs b/compiler/rustc_middle/src/ty/context/impl_interner.rs
index e59573976af52..5179a77d6cb6f 100644
--- a/compiler/rustc_middle/src/ty/context/impl_interner.rs
+++ b/compiler/rustc_middle/src/ty/context/impl_interner.rs
@@ -402,6 +402,11 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
         self.is_conditionally_const(def_id)
     }
 
+    fn closure_is_const(self, def_id: DefId) -> bool {
+        debug_assert_matches!(self.def_kind(def_id), DefKind::Closure);
+        self.constness(def_id) == hir::Constness::Const
+    }
+
     fn alias_has_const_conditions(self, def_id: DefId) -> bool {
         debug_assert_matches!(self.def_kind(def_id), DefKind::AssocTy | DefKind::OpaqueTy);
         self.is_conditionally_const(def_id)
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 6abe7d1466990..01c351de93198 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -2118,11 +2118,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 // FIXME(const_trait_impl): ATPITs could be conditionally const?
                 hir::OpaqueTyOrigin::TyAlias { .. } => false,
             },
-            DefKind::Closure => {
-                // Closures and RPITs will eventually have const conditions
-                // for `[const]` bounds.
-                false
-            }
+            DefKind::Closure => self.constness(def_id) == hir::Constness::Const,
             DefKind::Ctor(_, CtorKind::Const)
             | DefKind::Mod
             | DefKind::Struct
diff --git a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
index 05ea217c1de08..cd74e87b670f1 100644
--- a/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/assembly/structural_traits.rs
@@ -661,10 +661,11 @@ fn coroutine_closure_to_ambiguous_coroutine<I: Interner>(
 ///
 /// Doing so on all calls to `extract_tupled_inputs_and_output_from_callable`
 /// would be wasteful.
+#[instrument(level = "trace", skip(cx), ret)]
 pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
     cx: I,
     self_ty: I::Ty,
-) -> Result<(ty::Binder<I, (I::Ty, I::Ty)>, I::FunctionId, I::GenericArgs), NoSolution> {
+) -> Result<(ty::Binder<I, (I::Ty, I::Ty)>, I::DefId, I::GenericArgs), NoSolution> {
     match self_ty.kind() {
         ty::FnDef(def_id, args) => {
             let sig = cx.fn_sig(def_id);
@@ -675,7 +676,7 @@ pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
                 Ok((
                     sig.instantiate(cx, args)
                         .map_bound(|sig| (Ty::new_tup(cx, sig.inputs().as_slice()), sig.output())),
-                    def_id,
+                    def_id.into(),
                     args,
                 ))
             } else {
@@ -686,9 +687,19 @@ pub(in crate::solve) fn extract_fn_def_from_const_callable<I: Interner>(
         ty::FnPtr(..) => {
             return Err(NoSolution);
         }
-        // `Closure`s are not const for now.
-        ty::Closure(..) => {
-            return Err(NoSolution);
+        ty::Closure(def, args) => {
+            if cx.closure_is_const(def) {
+                let closure_args = args.as_closure();
+                Ok((
+                    closure_args
+                        .sig()
+                        .map_bound(|sig| (sig.inputs().get(0).unwrap(), sig.output())),
+                    def.into(),
+                    args,
+                ))
+            } else {
+                return Err(NoSolution);
+            }
         }
         // `CoroutineClosure`s are not const for now.
         ty::CoroutineClosure(..) => {
diff --git a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
index 4da76b88b5de0..4b1e4b2de571d 100644
--- a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
+++ b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs
@@ -272,6 +272,7 @@ where
         todo!("Fn* are not yet const")
     }
 
+    #[instrument(level = "trace", skip_all, ret)]
     fn consider_builtin_fn_trait_candidates(
         ecx: &mut EvalCtxt<'_, D>,
         goal: Goal<I, Self>,
@@ -289,7 +290,7 @@ where
         let output_is_sized_pred =
             ty::TraitRef::new(cx, cx.require_trait_lang_item(SolverTraitLangItem::Sized), [output]);
         let requirements = cx
-            .const_conditions(def_id.into())
+            .const_conditions(def_id)
             .iter_instantiated(cx, args)
             .map(|trait_ref| {
                 (
diff --git a/compiler/rustc_type_ir/src/interner.rs b/compiler/rustc_type_ir/src/interner.rs
index e77e7af071b90..25f7c36e9985d 100644
--- a/compiler/rustc_type_ir/src/interner.rs
+++ b/compiler/rustc_type_ir/src/interner.rs
@@ -308,6 +308,7 @@ pub trait Interner:
 
     fn impl_is_const(self, def_id: Self::ImplId) -> bool;
     fn fn_is_const(self, def_id: Self::FunctionId) -> bool;
+    fn closure_is_const(self, def_id: Self::ClosureId) -> bool;
     fn alias_has_const_conditions(self, def_id: Self::DefId) -> bool;
     fn const_conditions(
         self,
diff --git a/tests/ui/traits/const-traits/call.rs b/tests/ui/traits/const-traits/call.rs
index e93ea4ccbd708..41883f648513d 100644
--- a/tests/ui/traits/const-traits/call.rs
+++ b/tests/ui/traits/const-traits/call.rs
@@ -1,11 +1,10 @@
-// FIXME(const_trait_impl) check-pass
+//@ check-pass
 //@ compile-flags: -Znext-solver
 #![feature(const_closures, const_trait_impl)]
 #![allow(incomplete_features)]
 
 const _: () = {
     assert!((const || true)());
-    //~^ ERROR }: const Fn()` is not satisfied
 };
 
 fn main() {}
diff --git a/tests/ui/traits/const-traits/call.stderr b/tests/ui/traits/const-traits/call.stderr
deleted file mode 100644
index 3503938327a9f..0000000000000
--- a/tests/ui/traits/const-traits/call.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0277]: the trait bound `{closure@$DIR/call.rs:7:14: 7:22}: const Fn()` is not satisfied
-  --> $DIR/call.rs:7:13
-   |
-LL |     assert!((const || true)());
-   |             ^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.

From 60bd8e36cd8f2b534ba2979ddc04cef7a34dca32 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Fri, 13 Mar 2026 07:37:12 +0000
Subject: [PATCH 10/13] Enable the const_closures feature gate to silence an
 unrelated error

---
 .../ice-112822-expected-type-for-param.rs     |  5 +++--
 .../ice-112822-expected-type-for-param.stderr | 19 ++++---------------
 2 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
index 8ee3db445d072..d20abdd57f5c6 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
@@ -1,8 +1,9 @@
-#![feature(const_trait_impl)]
+#![feature(const_trait_impl, const_closures)]
+#![allow(incomplete_features)]
 
 const fn test() -> impl [const] Fn() {
     //~^ ERROR: }: [const] Fn()` is not satisfied
-    const move || { //~ ERROR const closures are experimental
+    const move || {
         let sl: &[u8] = b"foo";
 
         match sl {
diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
index abbe0a0070aa2..eebfd5c11e66e 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
@@ -1,20 +1,9 @@
-error[E0658]: const closures are experimental
-  --> $DIR/ice-112822-expected-type-for-param.rs:5:5
-   |
-LL |     const move || {
-   |     ^^^^^
-   |
-   = note: see issue #106003 <https://github.com/rust-lang/rust/issues/106003> for more information
-   = help: add `#![feature(const_closures)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
-error[E0277]: the trait bound `{closure@$DIR/ice-112822-expected-type-for-param.rs:5:5: 5:18}: [const] Fn()` is not satisfied
-  --> $DIR/ice-112822-expected-type-for-param.rs:3:20
+error[E0277]: the trait bound `{closure@$DIR/ice-112822-expected-type-for-param.rs:6:5: 6:18}: [const] Fn()` is not satisfied
+  --> $DIR/ice-112822-expected-type-for-param.rs:4:20
    |
 LL | const fn test() -> impl [const] Fn() {
    |                    ^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0277, E0658.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0277`.

From 8629126289a5d631ccae4d96384de18afde587eb Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Fri, 13 Mar 2026 07:47:24 +0000
Subject: [PATCH 11/13] Allow calling const closures on the old solver

---
 .../src/traits/effects.rs                     | 17 +++++++++---
 tests/ui/traits/const-traits/call.rs          |  3 ++-
 .../const-closure-parse-not-item.rs           |  3 +--
 .../const-closure-parse-not-item.stderr       |  9 -------
 tests/ui/traits/const-traits/gate.rs          |  3 ++-
 tests/ui/traits/const-traits/gate.stderr      | 26 +++++++++++++++----
 .../ice-112822-expected-type-for-param.rs     |  5 ++--
 .../ice-112822-expected-type-for-param.stderr | 14 ++++++----
 8 files changed, 51 insertions(+), 29 deletions(-)
 delete mode 100644 tests/ui/traits/const-traits/const-closure-parse-not-item.stderr

diff --git a/compiler/rustc_trait_selection/src/traits/effects.rs b/compiler/rustc_trait_selection/src/traits/effects.rs
index 66c949a38cea7..026ab3a527a1c 100644
--- a/compiler/rustc_trait_selection/src/traits/effects.rs
+++ b/compiler/rustc_trait_selection/src/traits/effects.rs
@@ -519,10 +519,21 @@ fn evaluate_host_effect_for_fn_goal<'tcx>(
         // We may support function pointers at some point in the future
         ty::FnPtr(..) => return Err(EvaluationFailure::NoSolution),
 
-        // Closures could implement `[const] Fn`,
+        // Coroutines could implement `[const] Fn`,
         // but they don't really need to right now.
-        ty::Closure(..) | ty::CoroutineClosure(_, _) => {
-            return Err(EvaluationFailure::NoSolution);
+        ty::CoroutineClosure(_, _) => return Err(EvaluationFailure::NoSolution),
+
+        ty::Closure(def, args) => {
+            // For now we limit ourselves to closures without binders. The next solver can handle them.
+            let sig =
+                args.as_closure().sig().no_bound_vars().ok_or(EvaluationFailure::NoSolution)?;
+            (
+                def,
+                tcx.mk_args_from_iter(
+                    [ty::GenericArg::from(*sig.inputs().get(0).unwrap()), sig.output().into()]
+                        .into_iter(),
+                ),
+            )
         }
 
         // Everything else needs explicit impls or cannot have an impl
diff --git a/tests/ui/traits/const-traits/call.rs b/tests/ui/traits/const-traits/call.rs
index 41883f648513d..0a76de9072328 100644
--- a/tests/ui/traits/const-traits/call.rs
+++ b/tests/ui/traits/const-traits/call.rs
@@ -1,5 +1,6 @@
 //@ check-pass
-//@ compile-flags: -Znext-solver
+//@[next] compile-flags: -Znext-solver
+//@revisions: next old
 #![feature(const_closures, const_trait_impl)]
 #![allow(incomplete_features)]
 
diff --git a/tests/ui/traits/const-traits/const-closure-parse-not-item.rs b/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
index 35127eda5c039..22ce427b6ab92 100644
--- a/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
+++ b/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
@@ -1,5 +1,4 @@
-//@ known-bug: #110395
-// FIXME check-pass
+//@check-pass
 
 #![feature(const_trait_impl, const_closures)]
 #![allow(incomplete_features)]
diff --git a/tests/ui/traits/const-traits/const-closure-parse-not-item.stderr b/tests/ui/traits/const-traits/const-closure-parse-not-item.stderr
deleted file mode 100644
index 1d8d5ff1b4f2e..0000000000000
--- a/tests/ui/traits/const-traits/const-closure-parse-not-item.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0277]: the trait bound `{closure@$DIR/const-closure-parse-not-item.rs:8:5: 8:18}: [const] Fn()` is not satisfied
-  --> $DIR/const-closure-parse-not-item.rs:7:20
-   |
-LL | const fn test() -> impl [const] Fn() {
-   |                    ^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/const-traits/gate.rs b/tests/ui/traits/const-traits/gate.rs
index 0821a45edb5e5..c9f56df35531f 100644
--- a/tests/ui/traits/const-traits/gate.rs
+++ b/tests/ui/traits/const-traits/gate.rs
@@ -3,7 +3,8 @@
 fn main() {
     const { (const || {})() };
     //~^ ERROR: const closures are experimental
-    //~| ERROR: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: const Fn()` is not satisfied
+    //~| ERROR: cannot call conditionally-const closure in constants
+    //~| ERROR:  `Fn` is not yet stable as a const trait
 }
 
 macro_rules! e {
diff --git a/tests/ui/traits/const-traits/gate.stderr b/tests/ui/traits/const-traits/gate.stderr
index af5905524437d..788878292b6ff 100644
--- a/tests/ui/traits/const-traits/gate.stderr
+++ b/tests/ui/traits/const-traits/gate.stderr
@@ -9,7 +9,7 @@ LL |     const { (const || {})() };
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0658]: const closures are experimental
-  --> $DIR/gate.rs:13:5
+  --> $DIR/gate.rs:14:5
    |
 LL | e!((const || {}));
    |     ^^^^^
@@ -18,13 +18,29 @@ LL | e!((const || {}));
    = help: add `#![feature(const_closures)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0277]: the trait bound `{closure@$DIR/gate.rs:4:14: 4:22}: const Fn()` is not satisfied
+error[E0658]: cannot call conditionally-const closure in constants
   --> $DIR/gate.rs:4:13
    |
 LL |     const { (const || {})() };
    |             ^^^^^^^^^^^^^^^
+   |
+   = note: closures need an RFC before allowed to be called in constants
+   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
+   = note: see issue #143874 <https://github.com/rust-lang/rust/issues/143874> for more information
+   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: `Fn` is not yet stable as a const trait
+  --> $DIR/gate.rs:4:13
+   |
+LL |     const { (const || {})() };
+   |             ^^^^^^^^^^^^^^^
+   |
+help: add `#![feature(const_trait_impl)]` to the crate attributes to enable
+   |
+LL + #![feature(const_trait_impl)]
+   |
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0277, E0658.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
index d20abdd57f5c6..832e88c189d60 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
@@ -1,15 +1,14 @@
-#![feature(const_trait_impl, const_closures)]
+#![feature(const_trait_impl, const_closures, const_cmp)]
 #![allow(incomplete_features)]
 
 const fn test() -> impl [const] Fn() {
-    //~^ ERROR: }: [const] Fn()` is not satisfied
     const move || {
         let sl: &[u8] = b"foo";
 
         match sl {
             [first, remainder @ ..] => {
                 assert_eq!(first, &b'f');
-                // FIXME(const_closures) ^ ERROR cannot call non-const function
+                //~^ ERROR cannot call non-const function
             }
             [] => panic!(),
         }
diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
index eebfd5c11e66e..7c6bec43ff40d 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
@@ -1,9 +1,13 @@
-error[E0277]: the trait bound `{closure@$DIR/ice-112822-expected-type-for-param.rs:6:5: 6:18}: [const] Fn()` is not satisfied
-  --> $DIR/ice-112822-expected-type-for-param.rs:4:20
+error[E0015]: cannot call non-const function `core::panicking::assert_failed::<&u8, &u8>` in constant functions
+  --> $DIR/ice-112822-expected-type-for-param.rs:10:17
    |
-LL | const fn test() -> impl [const] Fn() {
-   |                    ^^^^^^^^^^^^^^^^^
+LL |                 assert_eq!(first, &b'f');
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+note: function `assert_failed` is not const
+  --> $SRC_DIR/core/src/panicking.rs:LL:COL
+   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0015`.

From c521b8084fb910e4a809c0611944fc9404138615 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Fri, 13 Mar 2026 10:23:50 +0000
Subject: [PATCH 12/13] Remove the incomplete marker from const closures

---
 compiler/rustc_feature/src/unstable.rs                          | 2 +-
 tests/ui/traits/const-traits/call-const-closure.rs              | 1 -
 tests/ui/traits/const-traits/call-const-closure.stderr          | 2 +-
 tests/ui/traits/const-traits/call.rs                            | 1 -
 .../ui/traits/const-traits/const-closure-issue-125866-error.rs  | 1 -
 .../traits/const-traits/const-closure-issue-125866-error.stderr | 2 +-
 tests/ui/traits/const-traits/const-closure-parse-not-item.rs    | 1 -
 .../const-traits/const_closure-const_trait_impl-ice-113381.rs   | 1 -
 .../const_closure-const_trait_impl-ice-113381.stderr            | 2 +-
 .../traits/const-traits/ice-112822-expected-type-for-param.rs   | 1 -
 .../const-traits/ice-112822-expected-type-for-param.stderr      | 2 +-
 .../const-traits/non-const-op-const-closure-non-const-outer.rs  | 1 -
 .../non-const-op-const-closure-non-const-outer.stderr           | 2 +-
 13 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index 39e886227d946..ae356118c93ec 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -429,7 +429,7 @@ declare_features! (
     /// Allows defining and calling c-variadic functions in const contexts.
     (unstable, const_c_variadic, "1.95.0", Some(151787)),
     /// Allows `const || {}` closures in const contexts.
-    (incomplete, const_closures, "1.68.0", Some(106003)),
+    (unstable, const_closures, "1.68.0", Some(106003)),
     /// Allows using `[const] Destruct` bounds and calling drop impls in const contexts.
     (unstable, const_destruct, "1.85.0", Some(133214)),
     /// Allows `for _ in _` loops in const contexts.
diff --git a/tests/ui/traits/const-traits/call-const-closure.rs b/tests/ui/traits/const-traits/call-const-closure.rs
index a26f7be1148dd..c819df5d1d08d 100644
--- a/tests/ui/traits/const-traits/call-const-closure.rs
+++ b/tests/ui/traits/const-traits/call-const-closure.rs
@@ -2,7 +2,6 @@
 //@ edition:2021
 
 #![feature(const_trait_impl, const_closures)]
-#![allow(incomplete_features)]
 
 const trait Bar {
     fn foo(&self);
diff --git a/tests/ui/traits/const-traits/call-const-closure.stderr b/tests/ui/traits/const-traits/call-const-closure.stderr
index 16b936d58aaf6..7f4728b7e3218 100644
--- a/tests/ui/traits/const-traits/call-const-closure.stderr
+++ b/tests/ui/traits/const-traits/call-const-closure.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `(): const Bar` is not satisfied
-  --> $DIR/call-const-closure.rs:16:18
+  --> $DIR/call-const-closure.rs:15:18
    |
 LL |     (const || ().foo())();
    |                  ^^^
diff --git a/tests/ui/traits/const-traits/call.rs b/tests/ui/traits/const-traits/call.rs
index 0a76de9072328..71dea1ef4e049 100644
--- a/tests/ui/traits/const-traits/call.rs
+++ b/tests/ui/traits/const-traits/call.rs
@@ -2,7 +2,6 @@
 //@[next] compile-flags: -Znext-solver
 //@revisions: next old
 #![feature(const_closures, const_trait_impl)]
-#![allow(incomplete_features)]
 
 const _: () = {
     assert!((const || true)());
diff --git a/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs b/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
index e13ee39631a3a..55fae27eb6dd7 100644
--- a/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
+++ b/tests/ui/traits/const-traits/const-closure-issue-125866-error.rs
@@ -1,4 +1,3 @@
-#![allow(incomplete_features)]
 #![feature(const_closures, const_trait_impl)]
 
 const fn create_array<const N: usize>(mut f: impl FnMut(usize) -> u32 + Copy) -> [u32; N] {
diff --git a/tests/ui/traits/const-traits/const-closure-issue-125866-error.stderr b/tests/ui/traits/const-traits/const-closure-issue-125866-error.stderr
index 1eadd1d842691..448b343e2caa4 100644
--- a/tests/ui/traits/const-traits/const-closure-issue-125866-error.stderr
+++ b/tests/ui/traits/const-traits/const-closure-issue-125866-error.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `impl FnMut(usize) -> u32 + Copy: [const] FnMut(usize)` is not satisfied
-  --> $DIR/const-closure-issue-125866-error.rs:8:22
+  --> $DIR/const-closure-issue-125866-error.rs:7:22
    |
 LL |         array[i] = f(i);
    |                    - ^
diff --git a/tests/ui/traits/const-traits/const-closure-parse-not-item.rs b/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
index 22ce427b6ab92..ce20b05a8133c 100644
--- a/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
+++ b/tests/ui/traits/const-traits/const-closure-parse-not-item.rs
@@ -1,7 +1,6 @@
 //@check-pass
 
 #![feature(const_trait_impl, const_closures)]
-#![allow(incomplete_features)]
 
 const fn test() -> impl [const] Fn() {
     const move || {}
diff --git a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
index e355ee724d1bd..85613d9147a3e 100644
--- a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
+++ b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
@@ -1,7 +1,6 @@
 //@ known-bug: #110395
 //@ compile-flags: -Znext-solver
 #![feature(const_closures, const_trait_impl)]
-#![allow(incomplete_features)]
 
 trait Foo {
     fn foo(&self);
diff --git a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
index bbe736b94b5ba..2bafddd7cf788 100644
--- a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
+++ b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
@@ -1,5 +1,5 @@
 error: cannot use `const` closures outside of const contexts
-  --> $DIR/const_closure-const_trait_impl-ice-113381.rs:15:6
+  --> $DIR/const_closure-const_trait_impl-ice-113381.rs:14:6
    |
 LL |     (const || (()).foo())();
    |      ^^^^^
diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
index 832e88c189d60..1f35abbb9d6af 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.rs
@@ -1,5 +1,4 @@
 #![feature(const_trait_impl, const_closures, const_cmp)]
-#![allow(incomplete_features)]
 
 const fn test() -> impl [const] Fn() {
     const move || {
diff --git a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
index 7c6bec43ff40d..73340f15cbb8a 100644
--- a/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
+++ b/tests/ui/traits/const-traits/ice-112822-expected-type-for-param.stderr
@@ -1,5 +1,5 @@
 error[E0015]: cannot call non-const function `core::panicking::assert_failed::<&u8, &u8>` in constant functions
-  --> $DIR/ice-112822-expected-type-for-param.rs:10:17
+  --> $DIR/ice-112822-expected-type-for-param.rs:9:17
    |
 LL |                 assert_eq!(first, &b'f');
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
index a13fab3b21db2..58402cbaec81b 100644
--- a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
+++ b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.rs
@@ -1,5 +1,4 @@
 #![feature(const_closures, const_trait_impl)]
-#![allow(incomplete_features)]
 
 trait Foo {
     fn foo(&self);
diff --git a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
index 43c98ec7c661c..f5521b90cc2d9 100644
--- a/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
+++ b/tests/ui/traits/const-traits/non-const-op-const-closure-non-const-outer.stderr
@@ -1,5 +1,5 @@
 error: cannot use `const` closures outside of const contexts
-  --> $DIR/non-const-op-const-closure-non-const-outer.rs:15:6
+  --> $DIR/non-const-op-const-closure-non-const-outer.rs:14:6
    |
 LL |     (const || { (()).foo() })();
    |      ^^^^^

From 9503c31c8b132333e96ec9c40b4bb620643dd3d8 Mon Sep 17 00:00:00 2001
From: Oli Scherer <github@oli-obk.de>
Date: Fri, 13 Mar 2026 11:01:54 +0000
Subject: [PATCH 13/13] Some test cleanups

---
 ...sure.stderr => call-const-closure.next.stderr} |  2 +-
 .../const-traits/call-const-closure.old.stderr    | 14 ++++++++++++++
 .../ui/traits/const-traits/call-const-closure.rs  |  3 ++-
 .../const_closure-const_trait_impl-ice-113381.rs  | 15 ---------------
 ...nst_closure-const_trait_impl-ice-113381.stderr |  8 --------
 5 files changed, 17 insertions(+), 25 deletions(-)
 rename tests/ui/traits/const-traits/{call-const-closure.stderr => call-const-closure.next.stderr} (89%)
 create mode 100644 tests/ui/traits/const-traits/call-const-closure.old.stderr
 delete mode 100644 tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
 delete mode 100644 tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr

diff --git a/tests/ui/traits/const-traits/call-const-closure.stderr b/tests/ui/traits/const-traits/call-const-closure.next.stderr
similarity index 89%
rename from tests/ui/traits/const-traits/call-const-closure.stderr
rename to tests/ui/traits/const-traits/call-const-closure.next.stderr
index 7f4728b7e3218..16b936d58aaf6 100644
--- a/tests/ui/traits/const-traits/call-const-closure.stderr
+++ b/tests/ui/traits/const-traits/call-const-closure.next.stderr
@@ -1,5 +1,5 @@
 error[E0277]: the trait bound `(): const Bar` is not satisfied
-  --> $DIR/call-const-closure.rs:15:18
+  --> $DIR/call-const-closure.rs:16:18
    |
 LL |     (const || ().foo())();
    |                  ^^^
diff --git a/tests/ui/traits/const-traits/call-const-closure.old.stderr b/tests/ui/traits/const-traits/call-const-closure.old.stderr
new file mode 100644
index 0000000000000..16b936d58aaf6
--- /dev/null
+++ b/tests/ui/traits/const-traits/call-const-closure.old.stderr
@@ -0,0 +1,14 @@
+error[E0277]: the trait bound `(): const Bar` is not satisfied
+  --> $DIR/call-const-closure.rs:16:18
+   |
+LL |     (const || ().foo())();
+   |                  ^^^
+   |
+help: make the `impl` of trait `Bar` `const`
+   |
+LL | impl const Bar for () {
+   |      +++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/traits/const-traits/call-const-closure.rs b/tests/ui/traits/const-traits/call-const-closure.rs
index c819df5d1d08d..2cf561ae6db14 100644
--- a/tests/ui/traits/const-traits/call-const-closure.rs
+++ b/tests/ui/traits/const-traits/call-const-closure.rs
@@ -1,4 +1,5 @@
-//@ compile-flags: -Znext-solver
+//@[next] compile-flags: -Znext-solver
+//@ revisions: next old
 //@ edition:2021
 
 #![feature(const_trait_impl, const_closures)]
diff --git a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
deleted file mode 100644
index 85613d9147a3e..0000000000000
--- a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-//@ known-bug: #110395
-//@ compile-flags: -Znext-solver
-#![feature(const_closures, const_trait_impl)]
-
-trait Foo {
-    fn foo(&self);
-}
-
-impl Foo for () {
-    fn foo(&self) {}
-}
-
-fn main() {
-    (const || (()).foo())();
-}
diff --git a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr b/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
deleted file mode 100644
index 2bafddd7cf788..0000000000000
--- a/tests/ui/traits/const-traits/const_closure-const_trait_impl-ice-113381.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: cannot use `const` closures outside of const contexts
-  --> $DIR/const_closure-const_trait_impl-ice-113381.rs:14:6
-   |
-LL |     (const || (()).foo())();
-   |      ^^^^^
-
-error: aborting due to 1 previous error
-