Auto merge of rust-lang#136038 - compiler-errors:outlives, r=<try>

Simplify and consolidate the way we handle construct `OutlivesEnvironment` for lexical region resolution

... and also remove `region_bound_pairs` which is just totally redundant.

This is best reviewed commit-by-commit. I tried to consolidate the API for lexical region resolution *first*, then change the API when it was finally behind a single surface. Finally, I removed `region_bound_pairs` from borrowck + type outlives.

r? lcnr or reassign

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -1,6 +1,8 @@
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_errors::ErrorGuaranteed;
+use rustc_hir::OpaqueTyOrigin;
 use rustc_hir::def_id::LocalDefId;
+use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin, TyCtxtInferExt as _};
 use rustc_macros::extension;
 use rustc_middle::ty::fold::fold_regions;
@@ -10,6 +12,7 @@ use rustc_middle::ty::{
     TypingMode,
 };
 use rustc_span::Span;
+use rustc_trait_selection::regions::OutlivesEnvironmentBuildExt;
 use rustc_trait_selection::traits::ObligationCtxt;
 use tracing::{debug, instrument};
 
@@ -406,20 +409,16 @@ impl<'tcx> LazyOpaqueTyEnv<'tcx> {
     }
 
     fn get_canonical_args(&self) -> ty::GenericArgsRef<'tcx> {
-        use rustc_hir as hir;
-        use rustc_infer::infer::outlives::env::OutlivesEnvironment;
-        use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
-
         if let Some(&canonical_args) = self.canonical_args.get() {
             return canonical_args;
         }
 
         let &Self { tcx, def_id, .. } = self;
         let origin = tcx.local_opaque_ty_origin(def_id);
         let parent = match origin {
-            hir::OpaqueTyOrigin::FnReturn { parent, .. }
-            | hir::OpaqueTyOrigin::AsyncFn { parent, .. }
-            | hir::OpaqueTyOrigin::TyAlias { parent, .. } => parent,
+            OpaqueTyOrigin::FnReturn { parent, .. }
+            | OpaqueTyOrigin::AsyncFn { parent, .. }
+            | OpaqueTyOrigin::TyAlias { parent, .. } => parent,
         };
         let param_env = tcx.param_env(parent);
         let args = GenericArgs::identity_for_item(tcx, parent).extend_to(
@@ -439,8 +438,7 @@ impl<'tcx> LazyOpaqueTyEnv<'tcx> {
             tcx.dcx().span_delayed_bug(tcx.def_span(def_id), "error getting implied bounds");
             Default::default()
         });
-        let implied_bounds = infcx.implied_bounds_tys(param_env, parent, &wf_tys);
-        let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
+        let outlives_env = OutlivesEnvironment::new(&infcx, parent, param_env, wf_tys);
 
         let mut seen = vec![tcx.lifetimes.re_static];
         let canonical_args = fold_regions(tcx, args, |r1, _| {

compiler/rustc_hir_analysis/src/check/check.rs

@@ -27,7 +27,6 @@ use rustc_session::lint::builtin::UNINHABITED_STATIC;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::error_reporting::traits::on_unimplemented::OnUnimplementedDirective;
 use rustc_trait_selection::traits;
-use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_type_ir::fold::TypeFoldable;
 use tracing::{debug, instrument};
 use ty::TypingMode;
@@ -417,9 +416,7 @@ fn check_opaque_meets_bounds<'tcx>(
     }
 
     let wf_tys = ocx.assumed_wf_types_and_report_errors(param_env, defining_use_anchor)?;
-    let implied_bounds = infcx.implied_bounds_tys(param_env, def_id, &wf_tys);
-    let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
-    ocx.resolve_regions_and_report_errors(defining_use_anchor, &outlives_env)?;
+    ocx.resolve_regions_and_report_errors(defining_use_anchor, param_env, wf_tys)?;
 
     if infcx.next_trait_solver() {
         Ok(())

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -9,7 +9,6 @@ use rustc_errors::{Applicability, ErrorGuaranteed, pluralize, struct_span_code_e
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::VisitorExt;
 use rustc_hir::{self as hir, AmbigArg, GenericParamKind, ImplItemKind, intravisit};
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::util;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -24,7 +23,6 @@ use rustc_span::Span;
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::regions::InferCtxtRegionExt;
-use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
     self, FulfillmentError, ObligationCause, ObligationCauseCode, ObligationCtxt,
 };
@@ -416,11 +414,7 @@ fn compare_method_predicate_entailment<'tcx>(
 
     // Finally, resolve all regions. This catches wily misuses of
     // lifetime parameters.
-    let outlives_env = OutlivesEnvironment::with_bounds(
-        param_env,
-        infcx.implied_bounds_tys(param_env, impl_m_def_id, &wf_tys),
-    );
-    let errors = infcx.resolve_regions(&outlives_env);
+    let errors = infcx.resolve_regions(impl_m_def_id, param_env, wf_tys);
     if !errors.is_empty() {
         return Err(infcx
             .tainted_by_errors()
@@ -725,11 +719,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>(
 
     // Finally, resolve all regions. This catches wily misuses of
     // lifetime parameters.
-    let outlives_env = OutlivesEnvironment::with_bounds(
-        param_env,
-        infcx.implied_bounds_tys(param_env, impl_m_def_id, &wf_tys),
-    );
-    ocx.resolve_regions_and_report_errors(impl_m_def_id, &outlives_env)?;
+    ocx.resolve_regions_and_report_errors(impl_m_def_id, param_env, wf_tys)?;
 
     let mut remapped_types = DefIdMap::default();
     for (def_id, (ty, args)) in collected_types {
@@ -1883,8 +1873,7 @@ fn compare_const_predicate_entailment<'tcx>(
         return Err(infcx.err_ctxt().report_fulfillment_errors(errors));
     }
 
-    let outlives_env = OutlivesEnvironment::new(param_env);
-    ocx.resolve_regions_and_report_errors(impl_ct_def_id, &outlives_env)
+    ocx.resolve_regions_and_report_errors(impl_ct_def_id, param_env, [])
 }
 
 #[instrument(level = "debug", skip(tcx))]
@@ -2017,8 +2006,7 @@ fn compare_type_predicate_entailment<'tcx>(
 
     // Finally, resolve all regions. This catches wily misuses of
     // lifetime parameters.
-    let outlives_env = OutlivesEnvironment::new(param_env);
-    ocx.resolve_regions_and_report_errors(impl_ty_def_id, &outlives_env)
+    ocx.resolve_regions_and_report_errors(impl_ty_def_id, param_env, [])
 }
 
 /// Validate that `ProjectionCandidate`s created for this associated type will
@@ -2147,9 +2135,7 @@ pub(super) fn check_type_bounds<'tcx>(
 
     // Finally, resolve all regions. This catches wily misuses of
     // lifetime parameters.
-    let implied_bounds = infcx.implied_bounds_tys(param_env, impl_ty_def_id, &assumed_wf_types);
-    let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
-    ocx.resolve_regions_and_report_errors(impl_ty_def_id, &outlives_env)
+    ocx.resolve_regions_and_report_errors(impl_ty_def_id, param_env, assumed_wf_types)
 }
 
 struct ReplaceTy<'tcx> {

compiler/rustc_hir_analysis/src/check/compare_impl_item/refine.rs

@@ -3,7 +3,6 @@ use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_infer::infer::TyCtxtInferExt;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_lint_defs::builtin::{REFINING_IMPL_TRAIT_INTERNAL, REFINING_IMPL_TRAIT_REACHABLE};
 use rustc_middle::span_bug;
 use rustc_middle::traits::ObligationCause;
@@ -13,7 +12,6 @@ use rustc_middle::ty::{
 };
 use rustc_span::Span;
 use rustc_trait_selection::regions::InferCtxtRegionExt;
-use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt;
 use rustc_trait_selection::traits::{ObligationCtxt, elaborate, normalize_param_env_or_error};
 
 /// Check that an implementation does not refine an RPITIT from a trait method signature.
@@ -170,11 +168,7 @@ pub(crate) fn check_refining_return_position_impl_trait_in_trait<'tcx>(
         tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (selection)");
         return;
     }
-    let outlives_env = OutlivesEnvironment::with_bounds(
-        param_env,
-        infcx.implied_bounds_tys(param_env, impl_m.def_id.expect_local(), &implied_wf_types),
-    );
-    let errors = infcx.resolve_regions(&outlives_env);
+    let errors = infcx.resolve_regions(impl_m.def_id.expect_local(), param_env, implied_wf_types);
     if !errors.is_empty() {
         tcx.dcx().delayed_bug("encountered errors when checking RPITIT refinement (regions)");
         return;

compiler/rustc_hir_analysis/src/check/dropck.rs

@@ -5,7 +5,6 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::codes::*;
 use rustc_errors::{ErrorGuaranteed, struct_span_code_err};
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt};
 use rustc_infer::traits::{ObligationCause, ObligationCauseCode};
 use rustc_middle::ty::util::CheckRegions;
@@ -192,7 +191,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
         return Err(guar.unwrap());
     }
 
-    let errors = ocx.infcx.resolve_regions(&OutlivesEnvironment::new(adt_env));
+    let errors = ocx.infcx.resolve_regions(adt_def_id, adt_env, []);
     if !errors.is_empty() {
         let mut guar = None;
         for error in errors {

compiler/rustc_hir_analysis/src/check/mod.rs

@@ -80,7 +80,6 @@ use rustc_errors::{Diag, ErrorGuaranteed, pluralize, struct_span_code_err};
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit::Visitor;
 use rustc_index::bit_set::DenseBitSet;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{self, TyCtxtInferExt as _};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::query::Providers;
@@ -655,8 +654,7 @@ pub fn check_function_signature<'tcx>(
         }
     }
 
-    let outlives_env = OutlivesEnvironment::new(param_env);
-    if let Err(e) = ocx.resolve_regions_and_report_errors(local_id, &outlives_env) {
+    if let Err(e) = ocx.resolve_regions_and_report_errors(local_id, param_env, []) {
         return Err(e);
     }
 

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -25,11 +25,10 @@ use rustc_middle::{bug, span_bug};
 use rustc_session::parse::feature_err;
 use rustc_span::{DUMMY_SP, Ident, Span, sym};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
-use rustc_trait_selection::regions::InferCtxtRegionExt;
+use rustc_trait_selection::regions::{InferCtxtRegionExt, OutlivesEnvironmentBuildExt};
 use rustc_trait_selection::traits::misc::{
     ConstParamTyImplementationError, type_allowed_to_implement_const_param_ty,
 };
-use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use rustc_trait_selection::traits::{
     self, FulfillmentError, Obligation, ObligationCause, ObligationCauseCode, ObligationCtxt,
@@ -128,13 +127,17 @@ where
     let infcx_compat = infcx.fork();
 
     // We specifically want to call the non-compat version of `implied_bounds_tys`; we do this always.
-    let implied_bounds =
-        infcx.implied_bounds_tys_compat(param_env, body_def_id, &assumed_wf_types, false);
-    let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
+    let outlives_env = OutlivesEnvironment::new_with_implied_bounds_compat(
+        &infcx,
+        body_def_id,
+        param_env,
+        assumed_wf_types.iter().copied(),
+        false,
+    );
 
     lint_redundant_lifetimes(tcx, body_def_id, &outlives_env);
 
-    let errors = infcx.resolve_regions(&outlives_env);
+    let errors = infcx.resolve_regions_with_outlives_env(&outlives_env);
     if errors.is_empty() {
         return Ok(());
     }
@@ -172,10 +175,14 @@ where
     // 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 implied_bounds =
-            infcx_compat.implied_bounds_tys_compat(param_env, body_def_id, &assumed_wf_types, true);
-        let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
-        let errors_compat = infcx_compat.resolve_regions(&outlives_env);
+        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 {
@@ -769,12 +776,7 @@ fn test_region_obligations<'tcx>(
 
     add_constraints(&infcx);
 
-    let outlives_environment = OutlivesEnvironment::with_bounds(
-        param_env,
-        infcx.implied_bounds_tys(param_env, id, wf_tys),
-    );
-
-    let errors = infcx.resolve_regions(&outlives_environment);
+    let errors = infcx.resolve_regions(id, param_env, wf_tys.iter().copied());
     debug!(?errors, "errors");
 
     // If we were able to prove that the type outlives the region without

compiler/rustc_hir_analysis/src/coherence/builtin.rs

@@ -10,7 +10,6 @@ use rustc_hir as hir;
 use rustc_hir::ItemKind;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::{self, RegionResolutionError, TyCtxtInferExt};
 use rustc_infer::traits::Obligation;
 use rustc_middle::ty::adjustment::CoerceUnsizedInfo;
@@ -346,8 +345,7 @@ fn visit_implementation_of_dispatch_from_dyn(checker: &Checker<'_>) -> Result<()
                 }
 
                 // Finally, resolve all regions.
-                let outlives_env = OutlivesEnvironment::new(param_env);
-                res = res.and(ocx.resolve_regions_and_report_errors(impl_did, &outlives_env));
+                res = res.and(ocx.resolve_regions_and_report_errors(impl_did, param_env, []));
             }
             res
         }
@@ -564,8 +562,7 @@ pub(crate) fn coerce_unsized_info<'tcx>(
     }
 
     // Finally, resolve all regions.
-    let outlives_env = OutlivesEnvironment::new(param_env);
-    let _ = ocx.resolve_regions_and_report_errors(impl_did, &outlives_env);
+    let _ = ocx.resolve_regions_and_report_errors(impl_did, param_env, []);
 
     Ok(CoerceUnsizedInfo { custom_kind: kind })
 }

compiler/rustc_hir_analysis/src/impl_wf_check/min_specialization.rs

@@ -68,7 +68,6 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_infer::infer::TyCtxtInferExt;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::traits::ObligationCause;
 use rustc_infer::traits::specialization_graph::Node;
 use rustc_middle::ty::trait_def::TraitSpecializationKind;
@@ -77,7 +76,6 @@ use rustc_middle::ty::{
 };
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
-use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _;
 use rustc_trait_selection::traits::{self, ObligationCtxt, translate_args_with_cause, wf};
 use tracing::{debug, instrument};
 
@@ -176,7 +174,6 @@ fn get_impl_args(
     let ocx = ObligationCtxt::new_with_diagnostics(infcx);
     let param_env = tcx.param_env(impl1_def_id);
     let impl1_span = tcx.def_span(impl1_def_id);
-    let assumed_wf_types = ocx.assumed_wf_types_and_report_errors(param_env, impl1_def_id)?;
 
     let impl1_args = GenericArgs::identity_for_item(tcx, impl1_def_id);
     let impl2_args = translate_args_with_cause(
@@ -194,9 +191,8 @@ fn get_impl_args(
         return Err(guar);
     }
 
-    let implied_bounds = infcx.implied_bounds_tys(param_env, impl1_def_id, &assumed_wf_types);
-    let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds);
-    let _ = ocx.resolve_regions_and_report_errors(impl1_def_id, &outlives_env);
+    let assumed_wf_types = ocx.assumed_wf_types_and_report_errors(param_env, impl1_def_id)?;
+    let _ = ocx.resolve_regions_and_report_errors(impl1_def_id, param_env, assumed_wf_types);
     let Ok(impl2_args) = infcx.fully_resolve(impl2_args) else {
         let span = tcx.def_span(impl1_def_id);
         let guar = tcx.dcx().emit_err(GenericArgsOnOverriddenImpl { span });