From 933f9ebaae36c15ac917142033ec5f80e066d119 Mon Sep 17 00:00:00 2001
From: "leonardo.yvens" <leoyvens@gmail.com>
Date: Thu, 5 Apr 2018 15:21:56 -0300
Subject: [PATCH] Fix #49344

---
 src/librustc_typeck/check/wfcheck.rs          | 12 +++++++++---
 src/test/run-pass/defaults-well-formedness.rs |  4 ++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/librustc_typeck/check/wfcheck.rs b/src/librustc_typeck/check/wfcheck.rs
index 406ff9463a0..7dc73a1d5f0 100644
--- a/src/librustc_typeck/check/wfcheck.rs
+++ b/src/librustc_typeck/check/wfcheck.rs
@@ -423,12 +423,18 @@ fn check_where_clauses<'a, 'gcx, 'fcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'gcx>,
                     _ => t.super_visit_with(self)
                 }
             }
+
+            fn visit_region(&mut self, _: ty::Region<'tcx>) -> bool {
+                true
+            }
         }
         let mut param_count = CountParams { params: FxHashSet() };
-        pred.visit_with(&mut param_count);
+        let has_region = pred.visit_with(&mut param_count);
         let substituted_pred = pred.subst(fcx.tcx, substs);
-        // Don't check non-defaulted params, dependent defaults or preds with multiple params.
-        if substituted_pred.references_error() || param_count.params.len() > 1 {
+        // Don't check non-defaulted params, dependent defaults (including lifetimes)
+        // or preds with multiple params.
+        if substituted_pred.references_error() || param_count.params.len() > 1
+            || has_region {
             continue;
         }
         // Avoid duplication of predicates that contain no parameters, for example.
diff --git a/src/test/run-pass/defaults-well-formedness.rs b/src/test/run-pass/defaults-well-formedness.rs
index f3594679095..9b06bf837ae 100644
--- a/src/test/run-pass/defaults-well-formedness.rs
+++ b/src/test/run-pass/defaults-well-formedness.rs
@@ -27,4 +27,8 @@ trait SelfBound<T: Copy=Self> {}
 // Not even for well-formedness.
 struct WellFormedProjection<A, T=<A as Iterator>::Item>(A, T);
 
+// Issue #49344, predicates with lifetimes should not be checked.
+trait Scope<'a> {}
+struct Request<'a, S: Scope<'a> = i32>(S, &'a ());
+
 fn main() {}