Add -Zno-implied-bounds-compat option and use it

2 files changed, 17 insertions, 3 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs
index 52de8c4ceae..0cd376fcbbd 100644
--- a/compiler/rustc_trait_selection/src/traits/misc.rs
+++ b/compiler/rustc_trait_selection/src/traits/misc.rs
@@ -191,7 +191,7 @@ pub fn all_fields_implement_trait<'tcx>(
             // Check regions assuming the self type of the impl is WF
             let outlives_env = OutlivesEnvironment::with_bounds(
                 param_env,
-                infcx.implied_bounds_tys_compat(
+                infcx.implied_bounds_tys(
                     param_env,
                     parent_cause.body_id,
                     &FxIndexSet::from_iter([self_type]),
diff --git a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
index ec17024345a..52631d4353b 100644
--- a/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
+++ b/compiler/rustc_trait_selection/src/traits/outlives_bounds.rs
@@ -12,13 +12,17 @@ pub use rustc_middle::traits::query::OutlivesBound;
 pub type BoundsCompat<'a, 'tcx: 'a> = impl Iterator<Item = OutlivesBound<'tcx>> + 'a;
 pub type Bounds<'a, 'tcx: 'a> = impl Iterator<Item = OutlivesBound<'tcx>> + 'a;
 pub trait InferCtxtExt<'a, 'tcx> {
+    /// Do *NOT* call this directly.
     fn implied_bounds_tys_compat(
         &'a self,
         param_env: ty::ParamEnv<'tcx>,
         body_id: LocalDefId,
         tys: &'a FxIndexSet<Ty<'tcx>>,
+        compat: bool,
     ) -> BoundsCompat<'a, 'tcx>;
 
+    /// If `-Z no-implied-bounds-compat` is set, calls `implied_bounds_tys_compat`
+    /// with `compat` set to `true`, otherwise `false`.
     fn implied_bounds_tys(
         &'a self,
         param_env: ty::ParamEnv<'tcx>,
@@ -132,8 +136,10 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> {
         param_env: ParamEnv<'tcx>,
         body_id: LocalDefId,
         tys: &'a FxIndexSet<Ty<'tcx>>,
+        compat: bool,
     ) -> BoundsCompat<'a, 'tcx> {
-        tys.iter().flat_map(move |ty| implied_outlives_bounds(self, param_env, body_id, *ty, true))
+        tys.iter()
+            .flat_map(move |ty| implied_outlives_bounds(self, param_env, body_id, *ty, compat))
     }
 
     fn implied_bounds_tys(
@@ -142,6 +148,14 @@ impl<'a, 'tcx: 'a> InferCtxtExt<'a, 'tcx> for InferCtxt<'tcx> {
         body_id: LocalDefId,
         tys: &'a FxIndexSet<Ty<'tcx>>,
     ) -> Bounds<'a, 'tcx> {
-        tys.iter().flat_map(move |ty| implied_outlives_bounds(self, param_env, body_id, *ty, false))
+        tys.iter().flat_map(move |ty| {
+            implied_outlives_bounds(
+                self,
+                param_env,
+                body_id,
+                *ty,
+                !self.tcx.sess.opts.unstable_opts.no_implied_bounds_compat,
+            )
+        })
     }
 }