Rollup merge of #132344 - compiler-errors:same-thing, r=lcnr

Merge `HostPolarity` and `BoundConstness`

They're basically the same thing, and I think `BoundConstness` is easier to use.

r? fee1-dead or reassign

2 files changed, 7 insertions, 11 deletions

diff --git a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
index 6014ed555b6..612e92ea784 100644
--- a/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
+++ b/compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
@@ -545,10 +545,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                                 polarity: ty::PredicatePolarity::Positive,
                             }),
                             None,
-                            Some(match predicate.host {
-                                ty::HostPolarity::Maybe => ty::BoundConstness::ConstIfConst,
-                                ty::HostPolarity::Const => ty::BoundConstness::Const,
-                            }),
+                            Some(predicate.constness),
                             None,
                             String::new(),
                         );
@@ -2238,18 +2235,16 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
                     (None, _) => Some(cannot_do_this),
                     // suggested using default post message
                     (
-                        Some(ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst),
+                        Some(ty::BoundConstness::Const | ty::BoundConstness::Maybe),
                         Some(AppendConstMessage::Default),
                     ) => Some(format!("{cannot_do_this} in const contexts")),
                     // overridden post message
                     (
-                        Some(ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst),
+                        Some(ty::BoundConstness::Const | ty::BoundConstness::Maybe),
                         Some(AppendConstMessage::Custom(custom_msg, _)),
                     ) => Some(format!("{cannot_do_this}{custom_msg}")),
                     // fallback to generic message
-                    (Some(ty::BoundConstness::Const | ty::BoundConstness::ConstIfConst), None) => {
-                        None
-                    }
+                    (Some(ty::BoundConstness::Const | ty::BoundConstness::Maybe), None) => None,
                 }
             })
             .unwrap_or_else(|| {
diff --git a/compiler/rustc_trait_selection/src/traits/effects.rs b/compiler/rustc_trait_selection/src/traits/effects.rs
index 60b3357810a..cb36f1a62db 100644
--- a/compiler/rustc_trait_selection/src/traits/effects.rs
+++ b/compiler/rustc_trait_selection/src/traits/effects.rs
@@ -47,7 +47,7 @@ fn match_candidate<'tcx>(
     obligation: &HostEffectObligation<'tcx>,
     candidate: ty::Binder<'tcx, ty::HostEffectPredicate<'tcx>>,
 ) -> Result<ThinVec<PredicateObligation<'tcx>>, NoSolution> {
-    if !candidate.skip_binder().host.satisfies(obligation.predicate.host) {
+    if !candidate.skip_binder().constness.satisfies(obligation.predicate.constness) {
         return Err(NoSolution);
     }
 
@@ -135,7 +135,8 @@ fn evaluate_host_effect_from_selection_candiate<'tcx>(
                             .map(|(trait_ref, _)| {
                                 obligation.with(
                                     tcx,
-                                    trait_ref.to_host_effect_clause(tcx, obligation.predicate.host),
+                                    trait_ref
+                                        .to_host_effect_clause(tcx, obligation.predicate.constness),
                                 )
                             }),
                     );