From 00b380b8cad11abd07299fd181173b3c9b1d869e Mon Sep 17 00:00:00 2001
From: Yuki Okushi <huyuumi.dev@gmail.com>
Date: Mon, 27 Jul 2020 20:41:53 +0900
Subject: [PATCH] More ensure stack to avoid segfault with increased
 `recursion_limit`

---
 .../traits/error_reporting/suggestions.rs     | 46 +++++++++++--------
 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
index 0632ce2319aee..432abee6d1cf9 100644
--- a/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
+++ b/src/librustc_trait_selection/traits/error_reporting/suggestions.rs
@@ -7,6 +7,7 @@ use crate::autoderef::Autoderef;
 use crate::infer::InferCtxt;
 use crate::traits::normalize_projection_type;
 
+use rustc_data_structures::stack::ensure_sufficient_stack;
 use rustc_errors::{error_code, struct_span_err, Applicability, DiagnosticBuilder, Style};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
@@ -1912,12 +1913,15 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
 
                 let parent_predicate = parent_trait_ref.without_const().to_predicate(tcx);
                 if !self.is_recursive_obligation(obligated_types, &data.parent_code) {
-                    self.note_obligation_cause_code(
-                        err,
-                        &parent_predicate,
-                        &data.parent_code,
-                        obligated_types,
-                    );
+                    // #74711: avoid a stack overflow
+                    ensure_sufficient_stack(|| {
+                        self.note_obligation_cause_code(
+                            err,
+                            &parent_predicate,
+                            &data.parent_code,
+                            obligated_types,
+                        )
+                    });
                 }
             }
             ObligationCauseCode::ImplDerivedObligation(ref data) => {
@@ -1928,22 +1932,28 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                     parent_trait_ref.skip_binder().self_ty()
                 ));
                 let parent_predicate = parent_trait_ref.without_const().to_predicate(tcx);
-                self.note_obligation_cause_code(
-                    err,
-                    &parent_predicate,
-                    &data.parent_code,
-                    obligated_types,
-                );
+                // #74711: avoid a stack overflow
+                ensure_sufficient_stack(|| {
+                    self.note_obligation_cause_code(
+                        err,
+                        &parent_predicate,
+                        &data.parent_code,
+                        obligated_types,
+                    )
+                });
             }
             ObligationCauseCode::DerivedObligation(ref data) => {
                 let parent_trait_ref = self.resolve_vars_if_possible(&data.parent_trait_ref);
                 let parent_predicate = parent_trait_ref.without_const().to_predicate(tcx);
-                self.note_obligation_cause_code(
-                    err,
-                    &parent_predicate,
-                    &data.parent_code,
-                    obligated_types,
-                );
+                // #74711: avoid a stack overflow
+                ensure_sufficient_stack(|| {
+                    self.note_obligation_cause_code(
+                        err,
+                        &parent_predicate,
+                        &data.parent_code,
+                        obligated_types,
+                    )
+                });
             }
             ObligationCauseCode::CompareImplMethodObligation { .. } => {
                 err.note(&format!(