Rollup merge of #137633 - compiler-errors:no-implied-bounds-hack-unless-bevy, r=lcnr

Only use implied bounds hack if bevy, and use deeply normalize in implied bounds hack

Consolidates the implied bounds computation mode into a single function, which deeply normalizes, and if it's in **compat** mode (for bevy), it extracts outlives bounds from the infcx.

Previously, we were using the implied bounds compat mode in two cases:
1. During WF, if it detects `ParamSet`
2. EVERYWHERE ELSE (lol) -- e.g. borrowck, predicate entailment, etc.

While I think this is fine, and the net effect was just that we emitted fewer diagnostics, it makes me uncomfortable that all crates were using the supposed "compat" code.

Fixes #137767

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -126,13 +126,14 @@ where
 
     let infcx_compat = infcx.fork();
 
-    // We specifically want to call the non-compat version of `implied_bounds_tys`; we do this always.
+    // We specifically want to *disable* the implied bounds hack, first,
+    // so we can detect when failures are due to bevy's implied bounds.
     let outlives_env = OutlivesEnvironment::new_with_implied_bounds_compat(
         &infcx,
         body_def_id,
         param_env,
         assumed_wf_types.iter().copied(),
-        false,
+        true,
     );
 
     lint_redundant_lifetimes(tcx, body_def_id, &outlives_env);
@@ -142,53 +143,22 @@ where
         return Ok(());
     }
 
-    let is_bevy = assumed_wf_types.visit_with(&mut ContainsBevyParamSet { tcx }).is_break();
-
-    // If we have set `no_implied_bounds_compat`, then do not attempt compatibility.
-    // We could also just always enter if `is_bevy`, and call `implied_bounds_tys`,
-    // but that does result in slightly more work when this option is set and
-    // just obscures what we mean here anyways. Let's just be explicit.
-    if is_bevy && !infcx.tcx.sess.opts.unstable_opts.no_implied_bounds_compat {
-        let outlives_env = OutlivesEnvironment::new_with_implied_bounds_compat(
-            &infcx,
-            body_def_id,
-            param_env,
-            assumed_wf_types,
-            true,
-        );
-        let errors_compat = infcx_compat.resolve_regions_with_outlives_env(&outlives_env);
-        if errors_compat.is_empty() {
-            Ok(())
-        } else {
-            Err(infcx_compat.err_ctxt().report_region_errors(body_def_id, &errors_compat))
-        }
+    let outlives_env = OutlivesEnvironment::new_with_implied_bounds_compat(
+        &infcx_compat,
+        body_def_id,
+        param_env,
+        assumed_wf_types,
+        // Don't *disable* the implied bounds hack; though this will only apply
+        // the implied bounds hack if this contains `bevy_ecs`'s `ParamSet` type.
+        false,
+    );
+    let errors_compat = infcx_compat.resolve_regions_with_outlives_env(&outlives_env);
+    if errors_compat.is_empty() {
+        // FIXME: Once we fix bevy, this would be the place to insert a warning
+        // to upgrade bevy.
+        Ok(())
     } else {
-        Err(infcx.err_ctxt().report_region_errors(body_def_id, &errors))
-    }
-}
-
-struct ContainsBevyParamSet<'tcx> {
-    tcx: TyCtxt<'tcx>,
-}
-
-impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsBevyParamSet<'tcx> {
-    type Result = ControlFlow<()>;
-
-    fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
-        // We only care to match `ParamSet<T>` or `&ParamSet<T>`.
-        match t.kind() {
-            ty::Adt(def, _) => {
-                if self.tcx.item_name(def.did()) == sym::ParamSet
-                    && self.tcx.crate_name(def.did().krate) == sym::bevy_ecs
-                {
-                    return ControlFlow::Break(());
-                }
-            }
-            ty::Ref(_, ty, _) => ty.visit_with(self)?,
-            _ => {}
-        }
-
-        ControlFlow::Continue(())
+        Err(infcx_compat.err_ctxt().report_region_errors(body_def_id, &errors_compat))
     }
 }
 

compiler/rustc_middle/src/query/keys.rs

@@ -508,6 +508,14 @@ impl<'tcx, T: Clone> Key for CanonicalQueryInput<'tcx, T> {
     }
 }
 
+impl<'tcx, T: Clone> Key for (CanonicalQueryInput<'tcx, T>, bool) {
+    type Cache<V> = DefaultCache<Self, V>;
+
+    fn default_span(&self, _tcx: TyCtxt<'_>) -> Span {
+        DUMMY_SP
+    }
+}
+
 impl Key for (Symbol, u32, u32) {
     type Cache<V> = DefaultCache<Self, V>;
 

compiler/rustc_middle/src/query/mod.rs

@@ -2262,22 +2262,13 @@ rustc_queries! {
         desc { "normalizing `{}`", goal.value }
     }
 
-    query implied_outlives_bounds_compat(
-        goal: CanonicalImpliedOutlivesBoundsGoal<'tcx>
-    ) -> Result<
-        &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>,
-        NoSolution,
-    > {
-        desc { "computing implied outlives bounds for `{}`", goal.canonical.value.value.ty }
-    }
-
     query implied_outlives_bounds(
-        goal: CanonicalImpliedOutlivesBoundsGoal<'tcx>
+        key: (CanonicalImpliedOutlivesBoundsGoal<'tcx>, bool)
     ) -> Result<
         &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>,
         NoSolution,
     > {
-        desc { "computing implied outlives bounds v2 for `{}`", goal.canonical.value.value.ty }
+        desc { "computing implied outlives bounds for `{}` (hack disabled = {:?})", key.0.canonical.value.value.ty, key.1 }
     }
 
     /// Do not call this query directly:

compiler/rustc_trait_selection/src/regions.rs

@@ -17,13 +17,7 @@ impl<'tcx> OutlivesEnvironment<'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         assumed_wf_tys: impl IntoIterator<Item = Ty<'tcx>>,
     ) -> Self {
-        Self::new_with_implied_bounds_compat(
-            infcx,
-            body_id,
-            param_env,
-            assumed_wf_tys,
-            !infcx.tcx.sess.opts.unstable_opts.no_implied_bounds_compat,
-        )
+        Self::new_with_implied_bounds_compat(infcx, body_id, param_env, assumed_wf_tys, false)
     }
 
     fn new_with_implied_bounds_compat(
@@ -31,7 +25,7 @@ impl<'tcx> OutlivesEnvironment<'tcx> {
         body_id: LocalDefId,
         param_env: ty::ParamEnv<'tcx>,
         assumed_wf_tys: impl IntoIterator<Item = Ty<'tcx>>,
-        implied_bounds_compat: bool,
+        disable_implied_bounds_hack: bool,
     ) -> Self {
         let mut bounds = vec![];
 
@@ -59,11 +53,11 @@ impl<'tcx> OutlivesEnvironment<'tcx> {
         OutlivesEnvironment::from_normalized_bounds(
             param_env,
             bounds,
-            infcx.implied_bounds_tys_with_compat(
+            infcx.implied_bounds_tys(
                 body_id,
                 param_env,
                 assumed_wf_tys,
-                implied_bounds_compat,
+                disable_implied_bounds_hack,
             ),
         )
     }

compiler/rustc_trait_selection/src/traits/outlives_bounds.rs

@@ -36,7 +36,7 @@ fn implied_outlives_bounds<'a, 'tcx>(
     param_env: ty::ParamEnv<'tcx>,
     body_id: LocalDefId,
     ty: Ty<'tcx>,
-    compat: bool,
+    disable_implied_bounds_hack: bool,
 ) -> Vec<OutlivesBound<'tcx>> {
     let ty = infcx.resolve_vars_if_possible(ty);
     let ty = OpportunisticRegionResolver::new(infcx).fold_ty(ty);
@@ -52,11 +52,8 @@ fn implied_outlives_bounds<'a, 'tcx>(
     let mut canonical_var_values = OriginalQueryValues::default();
     let input = ImpliedOutlivesBounds { ty };
     let canonical = infcx.canonicalize_query(param_env.and(input), &mut canonical_var_values);
-    let implied_bounds_result = if compat {
-        infcx.tcx.implied_outlives_bounds_compat(canonical)
-    } else {
-        infcx.tcx.implied_outlives_bounds(canonical)
-    };
+    let implied_bounds_result =
+        infcx.tcx.implied_outlives_bounds((canonical, disable_implied_bounds_hack));
     let Ok(canonical_result) = implied_bounds_result else {
         return vec![];
     };
@@ -110,14 +107,15 @@ fn implied_outlives_bounds<'a, 'tcx>(
 impl<'tcx> InferCtxt<'tcx> {
     /// Do *NOT* call this directly. You probably want to construct a `OutlivesEnvironment`
     /// instead if you're interested in the implied bounds for a given signature.
-    fn implied_bounds_tys_with_compat<Tys: IntoIterator<Item = Ty<'tcx>>>(
+    fn implied_bounds_tys<Tys: IntoIterator<Item = Ty<'tcx>>>(
         &self,
         body_id: LocalDefId,
         param_env: ParamEnv<'tcx>,
         tys: Tys,
-        compat: bool,
+        disable_implied_bounds_hack: bool,
     ) -> impl Iterator<Item = OutlivesBound<'tcx>> {
-        tys.into_iter()
-            .flat_map(move |ty| implied_outlives_bounds(self, param_env, body_id, ty, compat))
+        tys.into_iter().flat_map(move |ty| {
+            implied_outlives_bounds(self, param_env, body_id, ty, disable_implied_bounds_hack)
+        })
     }
 }

compiler/rustc_trait_selection/src/traits/query/type_op/implied_outlives_bounds.rs

@@ -1,15 +1,16 @@
+use std::ops::ControlFlow;
+
+use rustc_infer::infer::RegionObligation;
 use rustc_infer::infer::canonical::CanonicalQueryInput;
-use rustc_infer::infer::resolve::OpportunisticRegionResolver;
 use rustc_infer::traits::query::OutlivesBound;
 use rustc_infer::traits::query::type_op::ImpliedOutlivesBounds;
 use rustc_middle::infer::canonical::CanonicalQueryResponse;
 use rustc_middle::traits::ObligationCause;
-use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeFolder, TypeVisitableExt};
+use rustc_middle::ty::{self, ParamEnvAnd, Ty, TyCtxt, TypeVisitable, TypeVisitor};
 use rustc_span::def_id::CRATE_DEF_ID;
-use rustc_span::{DUMMY_SP, Span};
+use rustc_span::{DUMMY_SP, Span, sym};
 use rustc_type_ir::outlives::{Component, push_outlives_components};
 use smallvec::{SmallVec, smallvec};
-use tracing::debug;
 
 use crate::traits::query::NoSolution;
 use crate::traits::{ObligationCtxt, wf};
@@ -35,11 +36,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
         tcx: TyCtxt<'tcx>,
         canonicalized: CanonicalQueryInput<'tcx, ParamEnvAnd<'tcx, Self>>,
     ) -> Result<CanonicalQueryResponse<'tcx, Self::QueryResponse>, NoSolution> {
-        if tcx.sess.opts.unstable_opts.no_implied_bounds_compat {
-            tcx.implied_outlives_bounds(canonicalized)
-        } else {
-            tcx.implied_outlives_bounds_compat(canonicalized)
-        }
+        tcx.implied_outlives_bounds((canonicalized, false))
     }
 
     fn perform_locally_with_next_solver(
@@ -47,11 +44,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ImpliedOutlivesBounds<'tcx> {
         key: ParamEnvAnd<'tcx, Self>,
         span: Span,
     ) -> Result<Self::QueryResponse, NoSolution> {
-        if ocx.infcx.tcx.sess.opts.unstable_opts.no_implied_bounds_compat {
-            compute_implied_outlives_bounds_inner(ocx, key.param_env, key.value.ty, span)
-        } else {
-            compute_implied_outlives_bounds_compat_inner(ocx, key.param_env, key.value.ty, span)
-        }
+        compute_implied_outlives_bounds_inner(ocx, key.param_env, key.value.ty, span, false)
     }
 }
 
@@ -60,18 +53,15 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
     param_env: ty::ParamEnv<'tcx>,
     ty: Ty<'tcx>,
     span: Span,
+    disable_implied_bounds_hack: bool,
 ) -> Result<Vec<OutlivesBound<'tcx>>, NoSolution> {
-    let normalize_op = |ty| -> Result<_, NoSolution> {
+    let normalize_ty = |ty| -> Result<_, NoSolution> {
         // We must normalize the type so we can compute the right outlives components.
         // for example, if we have some constrained param type like `T: Trait<Out = U>`,
         // and we know that `&'a T::Out` is WF, then we want to imply `U: 'a`.
         let ty = ocx
             .deeply_normalize(&ObligationCause::dummy_with_span(span), param_env, ty)
             .map_err(|_| NoSolution)?;
-        if !ocx.select_all_or_error().is_empty() {
-            return Err(NoSolution);
-        }
-        let ty = OpportunisticRegionResolver::new(&ocx.infcx).fold_ty(ty);
         Ok(ty)
     };
 
@@ -81,7 +71,7 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
     // guaranteed to be a subset of the original type, so we need to store the
     // WF args we've computed in a set.
     let mut checked_wf_args = rustc_data_structures::fx::FxHashSet::default();
-    let mut wf_args = vec![ty.into(), normalize_op(ty)?.into()];
+    let mut wf_args = vec![ty.into(), normalize_ty(ty)?.into()];
 
     let mut outlives_bounds: Vec<OutlivesBound<'tcx>> = vec![];
 
@@ -96,8 +86,14 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
                 .into_iter()
                 .flatten()
         {
-            assert!(!obligation.has_escaping_bound_vars());
-            let Some(pred) = obligation.predicate.kind().no_bound_vars() else {
+            let pred = ocx
+                .deeply_normalize(
+                    &ObligationCause::dummy_with_span(span),
+                    param_env,
+                    obligation.predicate,
+                )
+                .map_err(|_| NoSolution)?;
+            let Some(pred) = pred.kind().no_bound_vars() else {
                 continue;
             };
             match pred {
@@ -130,7 +126,6 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
                     ty_a,
                     r_b,
                 ))) => {
-                    let ty_a = normalize_op(ty_a)?;
                     let mut components = smallvec![];
                     push_outlives_components(ocx.infcx.tcx, ty_a, &mut components);
                     outlives_bounds.extend(implied_bounds_from_components(r_b, components))
@@ -139,141 +134,48 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
         }
     }
 
+    // If we detect `bevy_ecs::*::ParamSet` in the WF args list (and `disable_implied_bounds_hack`
+    // or `-Zno-implied-bounds-compat` are not set), then use the registered outlives obligations
+    // as implied bounds.
+    if !disable_implied_bounds_hack
+        && !ocx.infcx.tcx.sess.opts.unstable_opts.no_implied_bounds_compat
+        && ty.visit_with(&mut ContainsBevyParamSet { tcx: ocx.infcx.tcx }).is_break()
+    {
+        for RegionObligation { sup_type, sub_region, .. } in
+            ocx.infcx.take_registered_region_obligations()
+        {
+            let mut components = smallvec![];
+            push_outlives_components(ocx.infcx.tcx, sup_type, &mut components);
+            outlives_bounds.extend(implied_bounds_from_components(sub_region, components));
+        }
+    }
+
     Ok(outlives_bounds)
 }
 
-pub fn compute_implied_outlives_bounds_compat_inner<'tcx>(
-    ocx: &ObligationCtxt<'_, 'tcx>,
-    param_env: ty::ParamEnv<'tcx>,
-    ty: Ty<'tcx>,
-    span: Span,
-) -> Result<Vec<OutlivesBound<'tcx>>, NoSolution> {
-    let tcx = ocx.infcx.tcx;
+struct ContainsBevyParamSet<'tcx> {
+    tcx: TyCtxt<'tcx>,
+}
 
-    // Sometimes when we ask what it takes for T: WF, we get back that
-    // U: WF is required; in that case, we push U onto this stack and
-    // process it next. Because the resulting predicates aren't always
-    // guaranteed to be a subset of the original type, so we need to store the
-    // WF args we've computed in a set.
-    let mut checked_wf_args = rustc_data_structures::fx::FxHashSet::default();
-    let mut wf_args = vec![ty.into()];
+impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsBevyParamSet<'tcx> {
+    type Result = ControlFlow<()>;
 
-    let mut outlives_bounds: Vec<ty::OutlivesPredicate<'tcx, ty::GenericArg<'tcx>>> = vec![];
-
-    while let Some(arg) = wf_args.pop() {
-        if !checked_wf_args.insert(arg) {
-            continue;
-        }
-
-        // Compute the obligations for `arg` to be well-formed. If `arg` is
-        // an unresolved inference variable, just instantiated an empty set
-        // -- because the return type here is going to be things we *add*
-        // to the environment, it's always ok for this set to be smaller
-        // than the ultimate set. (Note: normally there won't be
-        // unresolved inference variables here anyway, but there might be
-        // during typeck under some circumstances.)
-        //
-        // FIXME(@lcnr): It's not really "always fine", having fewer implied
-        // bounds can be backward incompatible, e.g. #101951 was caused by
-        // us not dealing with inference vars in `TypeOutlives` predicates.
-        let obligations =
-            wf::obligations(ocx.infcx, param_env, CRATE_DEF_ID, 0, arg, span).unwrap_or_default();
-
-        for obligation in obligations {
-            debug!(?obligation);
-            assert!(!obligation.has_escaping_bound_vars());
-
-            // While these predicates should all be implied by other parts of
-            // the program, they are still relevant as they may constrain
-            // inference variables, which is necessary to add the correct
-            // implied bounds in some cases, mostly when dealing with projections.
-            //
-            // Another important point here: we only register `Projection`
-            // predicates, since otherwise we might register outlives
-            // predicates containing inference variables, and we don't
-            // learn anything new from those.
-            if obligation.predicate.has_non_region_infer() {
-                match obligation.predicate.kind().skip_binder() {
-                    ty::PredicateKind::Clause(ty::ClauseKind::Projection(..))
-                    | ty::PredicateKind::AliasRelate(..) => {
-                        ocx.register_obligation(obligation.clone());
-                    }
-                    _ => {}
+    fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
+        // We only care to match `ParamSet<T>` or `&ParamSet<T>`.
+        match t.kind() {
+            ty::Adt(def, _) => {
+                if self.tcx.item_name(def.did()) == sym::ParamSet
+                    && self.tcx.crate_name(def.did().krate) == sym::bevy_ecs
+                {
+                    return ControlFlow::Break(());
                 }
             }
-
-            let pred = match obligation.predicate.kind().no_bound_vars() {
-                None => continue,
-                Some(pred) => pred,
-            };
-            match pred {
-                // FIXME(const_generics): Make sure that `<'a, 'b, const N: &'a &'b u32>` is sound
-                // if we ever support that
-                ty::PredicateKind::Clause(ty::ClauseKind::Trait(..))
-                | ty::PredicateKind::Clause(ty::ClauseKind::HostEffect(..))
-                | ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..))
-                | ty::PredicateKind::Subtype(..)
-                | ty::PredicateKind::Coerce(..)
-                | ty::PredicateKind::Clause(ty::ClauseKind::Projection(..))
-                | ty::PredicateKind::DynCompatible(..)
-                | ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))
-                | ty::PredicateKind::ConstEquate(..)
-                | ty::PredicateKind::Ambiguous
-                | ty::PredicateKind::NormalizesTo(..)
-                | ty::PredicateKind::AliasRelate(..) => {}
-
-                // We need to search through *all* WellFormed predicates
-                ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(arg)) => {
-                    wf_args.push(arg);
-                }
-
-                // We need to register region relationships
-                ty::PredicateKind::Clause(ty::ClauseKind::RegionOutlives(
-                    ty::OutlivesPredicate(r_a, r_b),
-                )) => outlives_bounds.push(ty::OutlivesPredicate(r_a.into(), r_b)),
-
-                ty::PredicateKind::Clause(ty::ClauseKind::TypeOutlives(ty::OutlivesPredicate(
-                    ty_a,
-                    r_b,
-                ))) => outlives_bounds.push(ty::OutlivesPredicate(ty_a.into(), r_b)),
-            }
+            ty::Ref(_, ty, _) => ty.visit_with(self)?,
+            _ => {}
         }
-    }
 
-    // This call to `select_all_or_error` is necessary to constrain inference variables, which we
-    // use further down when computing the implied bounds.
-    match ocx.select_all_or_error().as_slice() {
-        [] => (),
-        _ => return Err(NoSolution),
+        ControlFlow::Continue(())
     }
-
-    // We lazily compute the outlives components as
-    // `select_all_or_error` constrains inference variables.
-    let mut implied_bounds = Vec::new();
-    for ty::OutlivesPredicate(a, r_b) in outlives_bounds {
-        match a.unpack() {
-            ty::GenericArgKind::Lifetime(r_a) => {
-                implied_bounds.push(OutlivesBound::RegionSubRegion(r_b, r_a))
-            }
-            ty::GenericArgKind::Type(ty_a) => {
-                let mut ty_a = ocx.infcx.resolve_vars_if_possible(ty_a);
-                // Need to manually normalize in the new solver as `wf::obligations` does not.
-                if ocx.infcx.next_trait_solver() {
-                    ty_a = ocx
-                        .deeply_normalize(&ObligationCause::dummy_with_span(span), param_env, ty_a)
-                        .map_err(|_| NoSolution)?;
-                }
-                let mut components = smallvec![];
-                push_outlives_components(tcx, ty_a, &mut components);
-                implied_bounds.extend(implied_bounds_from_components(r_b, components))
-            }
-            ty::GenericArgKind::Const(_) => {
-                unreachable!("consts do not participate in outlives bounds")
-            }
-        }
-    }
-
-    Ok(implied_bounds)
 }
 
 /// When we have an implied bound that `T: 'a`, we can further break

compiler/rustc_traits/src/implied_outlives_bounds.rs

@@ -10,38 +10,28 @@ use rustc_middle::query::Providers;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::DUMMY_SP;
 use rustc_trait_selection::infer::InferCtxtBuilderExt;
-use rustc_trait_selection::traits::query::type_op::implied_outlives_bounds::{
-    compute_implied_outlives_bounds_compat_inner, compute_implied_outlives_bounds_inner,
-};
+use rustc_trait_selection::traits::query::type_op::implied_outlives_bounds::compute_implied_outlives_bounds_inner;
 use rustc_trait_selection::traits::query::{CanonicalImpliedOutlivesBoundsGoal, NoSolution};
 
 pub(crate) fn provide(p: &mut Providers) {
-    *p = Providers { implied_outlives_bounds_compat, ..*p };
     *p = Providers { implied_outlives_bounds, ..*p };
 }
 
-fn implied_outlives_bounds_compat<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    goal: CanonicalImpliedOutlivesBoundsGoal<'tcx>,
-) -> Result<
-    &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>,
-    NoSolution,
-> {
-    tcx.infer_ctxt().enter_canonical_trait_query(&goal, |ocx, key| {
-        let (param_env, ImpliedOutlivesBounds { ty }) = key.into_parts();
-        compute_implied_outlives_bounds_compat_inner(ocx, param_env, ty, DUMMY_SP)
-    })
-}
-
 fn implied_outlives_bounds<'tcx>(
     tcx: TyCtxt<'tcx>,
-    goal: CanonicalImpliedOutlivesBoundsGoal<'tcx>,
+    (goal, disable_implied_bounds_hack): (CanonicalImpliedOutlivesBoundsGoal<'tcx>, bool),
 ) -> Result<
     &'tcx Canonical<'tcx, canonical::QueryResponse<'tcx, Vec<OutlivesBound<'tcx>>>>,
     NoSolution,
 > {
     tcx.infer_ctxt().enter_canonical_trait_query(&goal, |ocx, key| {
         let (param_env, ImpliedOutlivesBounds { ty }) = key.into_parts();
-        compute_implied_outlives_bounds_inner(ocx, param_env, ty, DUMMY_SP)
+        compute_implied_outlives_bounds_inner(
+            ocx,
+            param_env,
+            ty,
+            DUMMY_SP,
+            disable_implied_bounds_hack,
+        )
     })
 }

tests/ui/associated-inherent-types/issue-109789.rs

@@ -20,5 +20,6 @@ fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
 //~| ERROR mismatched types
 //~| ERROR higher-ranked subtype error
 //~| ERROR higher-ranked subtype error
+//~| ERROR higher-ranked subtype error
 
 fn main() {}

tests/ui/associated-inherent-types/issue-109789.stderr

@@ -31,6 +31,14 @@ LL | fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
    |
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: aborting due to 4 previous errors
+error: higher-ranked subtype error
+  --> $DIR/issue-109789.rs:18:1
+   |
+LL | fn bar(_: Foo<for<'a> fn(&'a ())>::Assoc) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0308`.

tests/ui/associated-inherent-types/issue-111404-1.rs

@@ -12,5 +12,6 @@ fn bar(_: fn(Foo<for<'b> fn(Foo<fn(&'b ())>::Assoc)>::Assoc)) {}
 //~| ERROR mismatched types [E0308]
 //~| ERROR higher-ranked subtype error
 //~| ERROR higher-ranked subtype error
+//~| ERROR higher-ranked subtype error
 
 fn main() {}

tests/ui/associated-inherent-types/issue-111404-1.stderr

@@ -31,6 +31,14 @@ LL | fn bar(_: fn(Foo<for<'b> fn(Foo<fn(&'b ())>::Assoc)>::Assoc)) {}
    |
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: aborting due to 4 previous errors
+error: higher-ranked subtype error
+  --> $DIR/issue-111404-1.rs:10:1
+   |
+LL | fn bar(_: fn(Foo<for<'b> fn(Foo<fn(&'b ())>::Assoc)>::Assoc)) {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 5 previous errors
 
 For more information about this error, try `rustc --explain E0308`.

tests/ui/implied-bounds/from-trait-impl.rs

@@ -12,6 +12,7 @@ where
 
 fn func1(foo: Foo<(&str,)>) {
     //~^ ERROR `&str` does not fulfill the required lifetime
+    //~| ERROR lifetime may not live long enough
     let _: &'static str = foo.0.0;
 }
 
@@ -19,5 +20,6 @@ trait TestTrait {}
 
 impl<X> TestTrait for [Foo<(X,)>; 1] {}
 //~^ ERROR `X` may not live long enough
+//~| ERROR `X` may not live long enough
 
 fn main() {}

tests/ui/implied-bounds/from-trait-impl.stderr

@@ -7,7 +7,21 @@ LL | fn func1(foo: Foo<(&str,)>) {
    = note: type must satisfy the static lifetime
 
 error[E0310]: the parameter type `X` may not live long enough
-  --> $DIR/from-trait-impl.rs:20:23
+  --> $DIR/from-trait-impl.rs:21:1
+   |
+LL | impl<X> TestTrait for [Foo<(X,)>; 1] {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   | |
+   | the parameter type `X` must be valid for the static lifetime...
+   | ...so that the type `X` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound
+   |
+LL | impl<X: 'static> TestTrait for [Foo<(X,)>; 1] {}
+   |       +++++++++
+
+error[E0310]: the parameter type `X` may not live long enough
+  --> $DIR/from-trait-impl.rs:21:23
    |
 LL | impl<X> TestTrait for [Foo<(X,)>; 1] {}
    |                       ^^^^^^^^^^^^^^
@@ -20,7 +34,16 @@ help: consider adding an explicit lifetime bound
 LL | impl<X: 'static> TestTrait for [Foo<(X,)>; 1] {}
    |       +++++++++
 
-error: aborting due to 2 previous errors
+error: lifetime may not live long enough
+  --> $DIR/from-trait-impl.rs:13:1
+   |
+LL | fn func1(foo: Foo<(&str,)>) {
+   | ^^^^^^^^^^^^^^^^^^^-^^^^^^^
+   | |                  |
+   | |                  let's call the lifetime of this reference `'1`
+   | requires that `'1` must outlive `'static`
+
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0310, E0477.
 For more information about an error, try `rustc --explain E0310`.

tests/ui/implied-bounds/normalization-nested.lifetime.stderr

@@ -1,10 +0,0 @@
-error: lifetime may not live long enough
-  --> $DIR/normalization-nested.rs:40:5
-   |
-LL | pub fn test_borrowck<'x>(_: Map<Vec<&'x ()>>, s: &'x str) -> &'static str {
-   |                      -- lifetime `'x` defined here
-LL |     s
-   |     ^ returning this value requires that `'x` must outlive `'static`
-
-error: aborting due to 1 previous error
-

tests/ui/implied-bounds/normalization-nested.rs

@@ -3,9 +3,7 @@
 //
 //@ revisions: param_ty lifetime param_ty_no_compat lifetime_no_compat
 
-//@[param_ty] check-pass
-//@[param_ty_no_compat] check-pass
-//@[lifetime_no_compat] check-pass
+//@ check-pass
 //@[param_ty_no_compat] compile-flags: -Zno-implied-bounds-compat
 //@[lifetime_no_compat] compile-flags: -Zno-implied-bounds-compat
 
@@ -38,7 +36,6 @@ pub fn test_wfcheck<'x>(_: Map<Vec<&'x ()>>) {}
 
 pub fn test_borrowck<'x>(_: Map<Vec<&'x ()>>, s: &'x str) -> &'static str {
     s
-    //[lifetime]~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}

tests/ui/implied-bounds/normalization-placeholder-leak.fail.stderr

@@ -1,3 +1,9 @@
+error[E0477]: the type `&'lt u8` does not fulfill the required lifetime
+  --> $DIR/normalization-placeholder-leak.rs:31:5
+   |
+LL |     fn test_lifetime<'lt, T: Trait>(_: Foo<&'lt u8>) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
 error[E0477]: the type `&'lt u8` does not fulfill the required lifetime
   --> $DIR/normalization-placeholder-leak.rs:31:40
    |
@@ -5,11 +11,35 @@ LL |     fn test_lifetime<'lt, T: Trait>(_: Foo<&'lt u8>) {}
    |                                        ^^^^^^^^^^^^
 
 error[E0477]: the type `<T as AnotherTrait>::Ty2<'lt>` does not fulfill the required lifetime
-  --> $DIR/normalization-placeholder-leak.rs:36:44
+  --> $DIR/normalization-placeholder-leak.rs:38:5
+   |
+LL |     fn test_alias<'lt, T: AnotherTrait>(_: Foo<T::Ty2::<'lt>>) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0477]: the type `<T as AnotherTrait>::Ty2<'lt>` does not fulfill the required lifetime
+  --> $DIR/normalization-placeholder-leak.rs:38:44
    |
 LL |     fn test_alias<'lt, T: AnotherTrait>(_: Foo<T::Ty2::<'lt>>) {}
    |                                            ^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 2 previous errors
+error: lifetime may not live long enough
+  --> $DIR/normalization-placeholder-leak.rs:31:5
+   |
+LL |     fn test_lifetime<'lt, T: Trait>(_: Foo<&'lt u8>) {}
+   |     ^^^^^^^^^^^^^^^^^---^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     |                |
+   |     |                lifetime `'lt` defined here
+   |     requires that `'lt` must outlive `'static`
+
+error: lifetime may not live long enough
+  --> $DIR/normalization-placeholder-leak.rs:38:5
+   |
+LL |     fn test_alias<'lt, T: AnotherTrait>(_: Foo<T::Ty2::<'lt>>) {}
+   |     ^^^^^^^^^^^^^^---^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |     |             |
+   |     |             lifetime `'lt` defined here
+   |     requires that `'lt` must outlive `'static`
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0477`.

tests/ui/implied-bounds/normalization-placeholder-leak.rs

@@ -30,11 +30,15 @@ mod fail {
     // don't use the bound to prove `'lt: 'static`.
     fn test_lifetime<'lt, T: Trait>(_: Foo<&'lt u8>) {}
     //[fail]~^ ERROR `&'lt u8` does not fulfill the required lifetime
+    //[fail]~| ERROR `&'lt u8` does not fulfill the required lifetime
+    //[fail]~| ERROR may not live long enough
 
     // implied bound: `T::Ty2<'lt>: placeholder('x)`.
     // don't use the bound to prove `T::Ty2<'lt>: 'static`.
     fn test_alias<'lt, T: AnotherTrait>(_: Foo<T::Ty2::<'lt>>) {}
     //[fail]~^ ERROR `<T as AnotherTrait>::Ty2<'lt>` does not fulfill the required lifetime
+    //[fail]~| ERROR `<T as AnotherTrait>::Ty2<'lt>` does not fulfill the required lifetime
+    //[fail]~| ERROR may not live long enough
 }
 
 

tests/ui/implied-bounds/sod_service_chain.rs

@@ -27,11 +27,19 @@ pub struct ServiceChainBuilder<P: Service, S: Service<Input = P::Output>> {
 }
 impl<P: Service, S: Service<Input = P::Output>> ServiceChainBuilder<P, S> {
     pub fn next<NS: Service<Input = S::Output>>(
+        //~^ the associated type
+        //~| the associated type
+        //~| the associated type
+        //~| the associated type
+        //~| the associated type
+        //~| the associated type
+        //~| may not live long enough
         self,
     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
         //~^ the associated type
         //~| the associated type
         //~| the associated type
+        //~| the associated type
         panic!();
     }
 }

tests/ui/implied-bounds/sod_service_chain.stderr

@@ -1,5 +1,39 @@
 error[E0310]: the associated type `<P as Service>::Error` may not live long enough
-  --> $DIR/sod_service_chain.rs:31:10
+  --> $DIR/sod_service_chain.rs:29:5
+   |
+LL | /     pub fn next<NS: Service<Input = S::Output>>(
+...  |
+LL | |         self,
+LL | |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
+   | |                                                    ^
+   | |                                                    |
+   | |____________________________________________________the associated type `<P as Service>::Error` must be valid for the static lifetime...
+   |                                                      ...so that the type `<P as Service>::Error` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound
+   |
+LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <P as Service>::Error: 'static {
+   |                                                      ++++++++++++++++++++++++++++++++++++
+
+error[E0310]: the associated type `<S as Service>::Error` may not live long enough
+  --> $DIR/sod_service_chain.rs:29:5
+   |
+LL | /     pub fn next<NS: Service<Input = S::Output>>(
+...  |
+LL | |         self,
+LL | |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
+   | |                                                    ^
+   | |                                                    |
+   | |____________________________________________________the associated type `<S as Service>::Error` must be valid for the static lifetime...
+   |                                                      ...so that the type `<S as Service>::Error` will meet its required lifetime bounds
+   |
+help: consider adding an explicit lifetime bound
+   |
+LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <S as Service>::Error: 'static {
+   |                                                      ++++++++++++++++++++++++++++++++++++
+
+error[E0310]: the associated type `<P as Service>::Error` may not live long enough
+  --> $DIR/sod_service_chain.rs:38:10
    |
 LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -13,7 +47,7 @@ LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <P as Service>::
    |                                                      ++++++++++++++++++++++++++++++++++++
 
 error[E0310]: the associated type `<S as Service>::Error` may not live long enough
-  --> $DIR/sod_service_chain.rs:31:10
+  --> $DIR/sod_service_chain.rs:38:10
    |
 LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -26,6 +60,42 @@ help: consider adding an explicit lifetime bound
 LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <S as Service>::Error: 'static {
    |                                                      ++++++++++++++++++++++++++++++++++++
 
-error: aborting due to 2 previous errors
+error[E0310]: the associated type `<P as Service>::Error` may not live long enough
+  --> $DIR/sod_service_chain.rs:29:5
+   |
+LL | /     pub fn next<NS: Service<Input = S::Output>>(
+...  |
+LL | |         self,
+LL | |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
+   | |                                                    ^
+   | |                                                    |
+   | |____________________________________________________the associated type `<P as Service>::Error` must be valid for the static lifetime...
+   |                                                      ...so that the type `<P as Service>::Error` will meet its required lifetime bounds
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: consider adding an explicit lifetime bound
+   |
+LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <P as Service>::Error: 'static {
+   |                                                      ++++++++++++++++++++++++++++++++++++
+
+error[E0310]: the associated type `<S as Service>::Error` may not live long enough
+  --> $DIR/sod_service_chain.rs:29:5
+   |
+LL | /     pub fn next<NS: Service<Input = S::Output>>(
+...  |
+LL | |         self,
+LL | |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> {
+   | |                                                    ^
+   | |                                                    |
+   | |____________________________________________________the associated type `<S as Service>::Error` must be valid for the static lifetime...
+   |                                                      ...so that the type `<S as Service>::Error` will meet its required lifetime bounds
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: consider adding an explicit lifetime bound
+   |
+LL |     ) -> ServiceChainBuilder<ServiceChain<P, S>, NS> where <S as Service>::Error: 'static {
+   |                                                      ++++++++++++++++++++++++++++++++++++
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0310`.