From 7fd8c00ae745111ba2e5adef527332d7162de068 Mon Sep 17 00:00:00 2001
From: Paul Backus <snarwin@gmail.com>
Date: Mon, 7 Jun 2021 10:53:42 -0400
Subject: [PATCH] Make matchImpl return auto ref again

Fixes #65 on Github, a regression introduced in 88b527bc (Github PR #50)
---
 src/sumtype.d | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/sumtype.d b/src/sumtype.d
index 282f4fe..5579989 100644
--- a/src/sumtype.d
+++ b/src/sumtype.d
@@ -1679,7 +1679,7 @@ private size_t stride(size_t dim, lengths...)()
 
 private template matchImpl(Flag!"exhaustive" exhaustive, handlers...)
 {
-	auto matchImpl(SumTypes...)(auto ref SumTypes args)
+	auto ref matchImpl(SumTypes...)(auto ref SumTypes args)
 		if (allSatisfy!(isSumType, SumTypes) && args.length > 0)
 	{
 		enum typeCount(SumType) = SumType.Types.length;
@@ -2111,6 +2111,15 @@ version (D_Exceptions)
 	assert(value.get!double.isClose(6.28));
 }
 
+// Handlers that return by ref
+@safe unittest {
+	SumType!int x = 123;
+
+	x.match!(ref (ref int n) => n) = 456;
+
+	assert(x.match!((int n) => n == 456));
+}
+
 // Unreachable handlers
 @safe unittest {
 	alias MySum = SumType!(int, string);