Rollup merge of #155907 - oli-obk:push-nypowoyskzxp, r=Kivooeo

jhpratt · web-flow · commit 8463b3a4ee86 · 2026-04-28T07:54:28.000-04:00
Handle hkl const closures I severely overthought this in #153818 😆 The const closure trait solver impl is now in sync with the non-const closure trait solver impl.
diff --git a/compiler/rustc_trait_selection/src/traits/effects.rs b/compiler/rustc_trait_selection/src/traits/effects.rs
@@ -554,11 +554,7 @@ fn evaluate_host_effect_for_fn_goal<'tcx>(
         // but they don't really need to right now.
         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.
-            args.as_closure().sig().no_bound_vars().ok_or(EvaluationFailure::NoSolution)?;
-            (def, args)
-        }
+        ty::Closure(def, args) => (def, args),
 
         // Everything else needs explicit impls or cannot have an impl
         _ => return Err(EvaluationFailure::NoSolution),
diff --git a/tests/ui/consts/const-closure-hkl.rs b/tests/ui/consts/const-closure-hkl.rs
@@ -0,0 +1,20 @@
+//! Regression test for hkl const closures not working in old solver
+
+//@ check-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
+
+#![feature(const_trait_impl)]
+#![feature(const_closures)]
+const fn partial_compare() {
+    let len_chain = const move |_a: &_, _b: &_| {};
+
+    chaining_impl(len_chain);
+}
+
+const fn chaining_impl(x: impl for<'a> [const] FnOnce(&'a usize, &'a usize)) {
+    std::mem::forget(x);
+}
+
+fn main() {}
