From 8f8cb710cc682cdb29d21cfa39af88c7e8534d76 Mon Sep 17 00:00:00 2001
From: Bastian Kauschke <bastian_kauschke@hotmail.de>
Date: Fri, 29 May 2020 21:04:01 +0200
Subject: [PATCH] remove trivial `mk_predicate`s

---
 src/librustc_middle/ty/structural_impls.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/librustc_middle/ty/structural_impls.rs b/src/librustc_middle/ty/structural_impls.rs
index c6ecb08615fcf..7eefd1419a311 100644
--- a/src/librustc_middle/ty/structural_impls.rs
+++ b/src/librustc_middle/ty/structural_impls.rs
@@ -987,7 +987,8 @@ impl<'tcx> TypeFoldable<'tcx> for ty::Region<'tcx> {
 
 impl<'tcx> TypeFoldable<'tcx> for ty::Predicate<'tcx> {
     fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
-        folder.tcx().mk_predicate(ty::PredicateKind::super_fold_with(self.kind, folder))
+        let new = ty::PredicateKind::super_fold_with(self.kind, folder);
+        if new != *self.kind { folder.tcx().mk_predicate(new) } else { *self }
     }
 
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {