stabilize `feature(trait_upcasting)`

1 files changed, 1 insertions, 62 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 13a6744c2e9..e495bdbf782 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -12,9 +12,7 @@ use hir::LangItem;
 use hir::def_id::DefId;
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
 use rustc_hir as hir;
-use rustc_infer::traits::{
-    Obligation, ObligationCause, PolyTraitObligation, PredicateObligations, SelectionError,
-};
+use rustc_infer::traits::{Obligation, PolyTraitObligation, SelectionError};
 use rustc_middle::ty::fast_reject::DeepRejectCtxt;
 use rustc_middle::ty::{self, Ty, TypeVisitableExt, TypingMode};
 use rustc_middle::{bug, span_bug};
@@ -23,8 +21,6 @@ use tracing::{debug, instrument, trace};
 
 use super::SelectionCandidate::*;
 use super::{BuiltinImplConditions, SelectionCandidateSet, SelectionContext, TraitObligationStack};
-use crate::traits;
-use crate::traits::query::evaluate_obligation::InferCtxtExt;
 use crate::traits::util;
 
 impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
@@ -904,54 +900,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         })
     }
 
-    /// Temporary migration for #89190
-    fn need_migrate_deref_output_trait_object(
-        &mut self,
-        ty: Ty<'tcx>,
-        param_env: ty::ParamEnv<'tcx>,
-        cause: &ObligationCause<'tcx>,
-    ) -> Option<ty::PolyExistentialTraitRef<'tcx>> {
-        // Don't drop any candidates in intercrate mode, as it's incomplete.
-        // (Not that it matters, since `Unsize` is not a stable trait.)
-        //
-        // FIXME(@lcnr): This should probably only trigger during analysis,
-        // disabling candidates during codegen is also questionable.
-        if let TypingMode::Coherence = self.infcx.typing_mode() {
-            return None;
-        }
-
-        let tcx = self.tcx();
-        if tcx.features().trait_upcasting() {
-            return None;
-        }
-
-        // <ty as Deref>
-        let trait_ref = ty::TraitRef::new(tcx, tcx.lang_items().deref_trait()?, [ty]);
-
-        let obligation =
-            traits::Obligation::new(tcx, cause.clone(), param_env, ty::Binder::dummy(trait_ref));
-        if !self.infcx.predicate_may_hold(&obligation) {
-            return None;
-        }
-
-        self.infcx.probe(|_| {
-            let ty = traits::normalize_projection_ty(
-                self,
-                param_env,
-                ty::AliasTy::new_from_args(tcx, tcx.lang_items().deref_target()?, trait_ref.args),
-                cause.clone(),
-                0,
-                // We're *intentionally* throwing these away,
-                // since we don't actually use them.
-                &mut PredicateObligations::new(),
-            )
-            .as_type()
-            .unwrap();
-
-            if let ty::Dynamic(data, ..) = ty.kind() { data.principal() } else { None }
-        })
-    }
-
     /// Searches for unsizing that might apply to `obligation`.
     fn assemble_candidates_for_unsizing(
         &mut self,
@@ -1019,15 +967,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     let principal_a = a_data.principal().unwrap();
                     let target_trait_did = principal_def_id_b.unwrap();
                     let source_trait_ref = principal_a.with_self_ty(self.tcx(), source);
-                    if let Some(deref_trait_ref) = self.need_migrate_deref_output_trait_object(
-                        source,
-                        obligation.param_env,
-                        &obligation.cause,
-                    ) {
-                        if deref_trait_ref.def_id() == target_trait_did {
-                            return;
-                        }
-                    }
 
                     for (idx, upcast_trait_ref) in
                         util::supertraits(self.tcx(), source_trait_ref).enumerate()