From f08a3371b01f6d6b01bf351f28bf0fbba2bd1b87 Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <n.nethercote@gmail.com>
Date: Fri, 3 Feb 2023 10:15:24 +1100
Subject: [PATCH] Improve early bailout test in `resolve_vars_if_possible`.

`!t.has_non_region_infer()` is the test used in
`OpportunisticVarResolver`, and catches a few cases that
`!t.needs_infer()` misses.
---
 compiler/rustc_infer/src/infer/mod.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index f39170bb2916..14af720fca1f 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -1389,8 +1389,8 @@ pub fn resolve_vars_if_possible<T>(&self, value: T) -> T
     where
         T: TypeFoldable<'tcx>,
     {
-        if !value.needs_infer() {
-            return value; // Avoid duplicated subst-folding.
+        if !value.has_non_region_infer() {
+            return value;
         }
         let mut r = resolve::OpportunisticVarResolver::new(self);
         value.fold_with(&mut r)