From 9918693037dce8aa4bb6f08741b6812923486c18 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 19 Jun 2024 11:26:03 +0200
Subject: Merging upstream version 1.76.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../rustc_trait_selection/src/traits/fulfill.rs    | 58 ++++++++++++++--------
 1 file changed, 38 insertions(+), 20 deletions(-)

(limited to 'compiler/rustc_trait_selection/src/traits/fulfill.rs')

diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs
index fb9cf51b5..045d7e444 100644
--- a/compiler/rustc_trait_selection/src/traits/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs
@@ -1,4 +1,5 @@
 use crate::infer::{InferCtxt, TyOrConstInferVar};
+use crate::traits::error_reporting::TypeErrCtxtExt;
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::obligation_forest::ProcessResult;
 use rustc_data_structures::obligation_forest::{Error, ForestObligation, Outcome};
@@ -115,12 +116,13 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
     fn register_predicate_obligation(
         &mut self,
         infcx: &InferCtxt<'tcx>,
-        obligation: PredicateObligation<'tcx>,
+        mut obligation: PredicateObligation<'tcx>,
     ) {
         assert_eq!(self.usable_in_snapshot, infcx.num_open_snapshots());
         // this helps to reduce duplicate errors, as well as making
         // debug output much nicer to read and so on.
-        let obligation = infcx.resolve_vars_if_possible(obligation);
+        debug_assert!(!obligation.param_env.has_non_region_infer());
+        obligation.predicate = infcx.resolve_vars_if_possible(obligation.predicate);
 
         debug!(?obligation, "register_predicate_obligation");
 
@@ -350,7 +352,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                 | ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..))
                 | ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_))
                 | ty::PredicateKind::ObjectSafe(_)
-                | ty::PredicateKind::ClosureKind(..)
                 | ty::PredicateKind::Subtype(_)
                 | ty::PredicateKind::Coerce(_)
                 | ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))
@@ -360,8 +361,11 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)]))
                 }
                 ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
+                ty::PredicateKind::NormalizesTo(..) => {
+                    bug!("NormalizesTo is only used by the new solver")
+                }
                 ty::PredicateKind::AliasRelate(..) => {
-                    bug!("AliasRelate is only used for new solver")
+                    bug!("AliasRelate is only used by the new solver")
                 }
             },
             Some(pred) => match pred {
@@ -411,17 +415,30 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                     }
                 }
 
-                ty::PredicateKind::ClosureKind(_, closure_args, kind) => {
-                    match self.selcx.infcx.closure_kind(closure_args) {
-                        Some(closure_kind) => {
-                            if closure_kind.extends(kind) {
-                                ProcessResult::Changed(vec![])
-                            } else {
-                                ProcessResult::Error(CodeSelectionError(Unimplemented))
-                            }
-                        }
-                        None => ProcessResult::Unchanged,
-                    }
+                ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
+                ty::PredicateKind::NormalizesTo(..) => {
+                    bug!("NormalizesTo is only used by the new solver")
+                }
+                ty::PredicateKind::AliasRelate(..) => {
+                    bug!("AliasRelate is only used by the new solver")
+                }
+
+                // General case overflow check. Allow `process_trait_obligation`
+                // and `process_projection_obligation` to handle checking for
+                // the recursion limit themselves. Also don't check some
+                // predicate kinds that don't give further obligations.
+                _ if !self
+                    .selcx
+                    .tcx()
+                    .recursion_limit()
+                    .value_within_limit(obligation.recursion_depth) =>
+                {
+                    self.selcx.infcx.err_ctxt().report_overflow_error(
+                        &obligation.predicate,
+                        obligation.cause.span,
+                        false,
+                        |_| {},
+                    );
                 }
 
                 ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(arg)) => {
@@ -454,7 +471,12 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                                 vec![TyOrConstInferVar::Ty(a), TyOrConstInferVar::Ty(b)];
                             ProcessResult::Unchanged
                         }
-                        Ok(Ok(ok)) => ProcessResult::Changed(mk_pending(ok.obligations)),
+                        Ok(Ok(mut ok)) => {
+                            for subobligation in &mut ok.obligations {
+                                subobligation.set_depth_from_parent(obligation.recursion_depth);
+                            }
+                            ProcessResult::Changed(mk_pending(ok.obligations))
+                        }
                         Ok(Err(err)) => {
                             let expected_found =
                                 ExpectedFound::new(subtype.a_is_expected, subtype.a, subtype.b);
@@ -625,10 +647,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
                         }
                     }
                 }
-                ty::PredicateKind::Ambiguous => ProcessResult::Unchanged,
-                ty::PredicateKind::AliasRelate(..) => {
-                    bug!("AliasRelate is only used for new solver")
-                }
                 ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(ct, ty)) => {
                     match self.selcx.infcx.at(&obligation.cause, obligation.param_env).eq(
                         DefineOpaqueTypes::No,
-- 
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