Auto merge of #106004 - fee1-dead-contrib:const-closures, r=oli-obk

Const closures

cc https://github.com/rust-lang/rust/issues/106003

3 files changed, 10 insertions, 4 deletions

diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 883554f959c..48bae7a2d4e 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -485,7 +485,9 @@ impl<'hir> Map<'hir> {
             BodyOwnerKind::Static(mt) => ConstContext::Static(mt),
 
             BodyOwnerKind::Fn if self.tcx.is_constructor(def_id.to_def_id()) => return None,
-            BodyOwnerKind::Fn if self.tcx.is_const_fn_raw(def_id.to_def_id()) => {
+            BodyOwnerKind::Fn | BodyOwnerKind::Closure
+                if self.tcx.is_const_fn_raw(def_id.to_def_id()) =>
+            {
                 ConstContext::ConstFn
             }
             BodyOwnerKind::Fn if self.tcx.is_const_default_method(def_id.to_def_id()) => {
diff --git a/compiler/rustc_middle/src/traits/select.rs b/compiler/rustc_middle/src/traits/select.rs
index ec69864c951..1cc9fd526b4 100644
--- a/compiler/rustc_middle/src/traits/select.rs
+++ b/compiler/rustc_middle/src/traits/select.rs
@@ -131,7 +131,9 @@ pub enum SelectionCandidate<'tcx> {
 
     /// Implementation of a `Fn`-family trait by one of the anonymous types
     /// generated for an `||` expression.
-    ClosureCandidate,
+    ClosureCandidate {
+        is_const: bool,
+    },
 
     /// Implementation of a `Generator` trait by one of the anonymous types
     /// generated for a generator.
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index fa571d480b6..993e95b3514 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -2465,8 +2465,10 @@ 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(..))
-            && self.constness(def_id) == hir::Constness::Const
+        matches!(
+            self.def_kind(def_id),
+            DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(..) | DefKind::Closure
+        ) && self.constness(def_id) == hir::Constness::Const
     }
 
     #[inline]