Revert "Auto merge of #92007 - oli-obk:lazy_tait2, r=nikomatsakis"

This reverts commit e7cc3bddbe, reversing
changes made to 734368a200.

compiler/rustc_middle/src/ty/mod.rs

@@ -627,11 +627,6 @@ pub enum PredicateKind<'tcx> {
     ///
     /// Only used for Chalk.
     TypeWellFormedFromEnv(Ty<'tcx>),
-
-    /// Represents a hidden type assignment for an opaque type.
-    /// Such obligations get processed by checking whether the item currently being
-    /// type-checked may acually define it.
-    OpaqueType(Ty<'tcx>, Ty<'tcx>),
 }
 
 /// The crate outlives map is computed during typeck and contains the
@@ -991,7 +986,6 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::TypeOutlives(..)
             | PredicateKind::ConstEvaluatable(..)
             | PredicateKind::ConstEquate(..)
-            | PredicateKind::OpaqueType(..)
             | PredicateKind::TypeWellFormedFromEnv(..) => None,
         }
     }
@@ -1010,7 +1004,6 @@ impl<'tcx> Predicate<'tcx> {
             | PredicateKind::ClosureKind(..)
             | PredicateKind::ConstEvaluatable(..)
             | PredicateKind::ConstEquate(..)
-            | PredicateKind::OpaqueType(..)
             | PredicateKind::TypeWellFormedFromEnv(..) => None,
         }
     }
@@ -1051,18 +1044,7 @@ impl<'tcx> InstantiatedPredicates<'tcx> {
     }
 }
 
-#[derive(
-    Copy,
-    Clone,
-    Debug,
-    PartialEq,
-    Eq,
-    HashStable,
-    TyEncodable,
-    TyDecodable,
-    TypeFoldable,
-    Lift
-)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, HashStable, TyEncodable, TyDecodable, TypeFoldable)]
 pub struct OpaqueTypeKey<'tcx> {
     pub def_id: DefId,
     pub substs: SubstsRef<'tcx>,