From 43883ee88f96c1d47f7f67ccab4d1c46fbb02e7f Mon Sep 17 00:00:00 2001
From: Stephen Toub <stoub@microsoft.com>
Date: Sun, 14 Feb 2021 22:42:21 -0500
Subject: [PATCH] Follow-up to Enumerable.Min/Max Comparer<T>.Default
 optimization

I didn't notice the same pattern was employed in the `Func<TSource, TResult>` overloads, so changing them, too.
---
 src/libraries/System.Linq/src/System/Linq/Max.cs | 13 +++++--------
 src/libraries/System.Linq/src/System/Linq/Min.cs | 13 +++++--------
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/src/libraries/System.Linq/src/System/Linq/Max.cs b/src/libraries/System.Linq/src/System/Linq/Max.cs
index 0e9c4c0476ae0c..c430306156400c 100644
--- a/src/libraries/System.Linq/src/System/Linq/Max.cs
+++ b/src/libraries/System.Linq/src/System/Linq/Max.cs
@@ -991,11 +991,10 @@ public static decimal Max<TSource>(this IEnumerable<TSource> source, Func<TSourc
                 ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
             }
 
-            Comparer<TResult> comparer = Comparer<TResult>.Default;
             TResult? value = default;
-            if (value == null)
+            using (IEnumerator<TSource> e = source.GetEnumerator())
             {
-                using (IEnumerator<TSource> e = source.GetEnumerator())
+                if (value == null)
                 {
                     do
                     {
@@ -1008,6 +1007,7 @@ public static decimal Max<TSource>(this IEnumerable<TSource> source, Func<TSourc
                     }
                     while (value == null);
 
+                    Comparer<TResult> comparer = Comparer<TResult>.Default;
                     while (e.MoveNext())
                     {
                         TResult x = selector(e.Current);
@@ -1017,10 +1017,7 @@ public static decimal Max<TSource>(this IEnumerable<TSource> source, Func<TSourc
                         }
                     }
                 }
-            }
-            else
-            {
-                using (IEnumerator<TSource> e = source.GetEnumerator())
+                else
                 {
                     if (!e.MoveNext())
                     {
@@ -1031,7 +1028,7 @@ public static decimal Max<TSource>(this IEnumerable<TSource> source, Func<TSourc
                     while (e.MoveNext())
                     {
                         TResult x = selector(e.Current);
-                        if (comparer.Compare(x, value) > 0)
+                        if (Comparer<TResult>.Default.Compare(x, value) > 0)
                         {
                             value = x;
                         }
diff --git a/src/libraries/System.Linq/src/System/Linq/Min.cs b/src/libraries/System.Linq/src/System/Linq/Min.cs
index f8c7f3bec469be..f9531778910a42 100644
--- a/src/libraries/System.Linq/src/System/Linq/Min.cs
+++ b/src/libraries/System.Linq/src/System/Linq/Min.cs
@@ -907,11 +907,10 @@ public static decimal Min<TSource>(this IEnumerable<TSource> source, Func<TSourc
                 ThrowHelper.ThrowArgumentNullException(ExceptionArgument.selector);
             }
 
-            Comparer<TResult> comparer = Comparer<TResult>.Default;
             TResult? value = default;
-            if (value == null)
+            using (IEnumerator<TSource> e = source.GetEnumerator())
             {
-                using (IEnumerator<TSource> e = source.GetEnumerator())
+                if (value == null)
                 {
                     do
                     {
@@ -924,6 +923,7 @@ public static decimal Min<TSource>(this IEnumerable<TSource> source, Func<TSourc
                     }
                     while (value == null);
 
+                    Comparer<TResult> comparer = Comparer<TResult>.Default;
                     while (e.MoveNext())
                     {
                         TResult x = selector(e.Current);
@@ -933,10 +933,7 @@ public static decimal Min<TSource>(this IEnumerable<TSource> source, Func<TSourc
                         }
                     }
                 }
-            }
-            else
-            {
-                using (IEnumerator<TSource> e = source.GetEnumerator())
+                else
                 {
                     if (!e.MoveNext())
                     {
@@ -947,7 +944,7 @@ public static decimal Min<TSource>(this IEnumerable<TSource> source, Func<TSourc
                     while (e.MoveNext())
                     {
                         TResult x = selector(e.Current);
-                        if (comparer.Compare(x, value) < 0)
+                        if (Comparer<TResult>.Default.Compare(x, value) < 0)
                         {
                             value = x;
                         }