Auto merge of #118607 - Mark-Simulacrum:stable-next, r=Mark-Simulacrum 1.74.1

[stable] 1.74.1 release

This includes backports of:

*  Dispose llvm::TargetMachines prior to llvm::Context being disposed #118464
*  clarify fn discriminant guarantees: only free lifetimes may get erased #118006
*  Move subtyper below reveal_all and change reveal_all #116415
   *  Make subtyping explicit in MIR #115025 (needed for above)

As well as infrastructure fix:

*  Don't ask for a specific branch in cargotest #118597

r? `@Mark-Simulacrum`

1 files changed, 15 insertions, 0 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/engine.rs b/compiler/rustc_trait_selection/src/traits/engine.rs
index 820973dc090..015e38b2ac0 100644
--- a/compiler/rustc_trait_selection/src/traits/engine.rs
+++ b/compiler/rustc_trait_selection/src/traits/engine.rs
@@ -23,6 +23,7 @@ use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::error::TypeError;
 use rustc_middle::ty::ToPredicate;
 use rustc_middle::ty::TypeFoldable;
+use rustc_middle::ty::Variance;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_session::config::TraitSolver;
 
@@ -156,6 +157,20 @@ impl<'a, 'tcx> ObligationCtxt<'a, 'tcx> {
             .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
     }
 
+    pub fn relate<T: ToTrace<'tcx>>(
+        &self,
+        cause: &ObligationCause<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        variance: Variance,
+        expected: T,
+        actual: T,
+    ) -> Result<(), TypeError<'tcx>> {
+        self.infcx
+            .at(cause, param_env)
+            .relate(DefineOpaqueTypes::Yes, expected, variance, actual)
+            .map(|infer_ok| self.register_infer_ok_obligations(infer_ok))
+    }
+
     /// Checks whether `expected` is a supertype of `actual`: `expected :> actual`.
     pub fn sup<T: ToTrace<'tcx>>(
         &self,