From 8860962e09fabd0c642b0156c51340a9f298e7db Mon Sep 17 00:00:00 2001
From: Max Kellermann <mk@cm4all.com>
Date: Wed, 30 Nov 2022 09:46:53 +0100
Subject: [PATCH] util/IntrusiveHashSet: make several methods `const`

---
 src/util/IntrusiveHashSet.hxx      | 6 +++---
 test/util/TestIntrusiveHashSet.cxx | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/util/IntrusiveHashSet.hxx b/src/util/IntrusiveHashSet.hxx
index 2766a5915..dc10674c9 100644
--- a/src/util/IntrusiveHashSet.hxx
+++ b/src/util/IntrusiveHashSet.hxx
@@ -155,12 +155,12 @@ public:
 	}
 
 	[[nodiscard]]
-	constexpr const key_equal key_eq() const noexcept {
+	constexpr const key_equal &key_eq() const noexcept {
 		return equal;
 	}
 
 	[[nodiscard]]
-	constexpr bool empty() noexcept {
+	constexpr bool empty() const noexcept {
 		if constexpr (constant_time_size)
 			return size() == 0;
 		else
@@ -170,7 +170,7 @@ public:
 	}
 
 	[[nodiscard]]
-	constexpr size_type size() noexcept {
+	constexpr size_type size() const noexcept {
 		if constexpr (constant_time_size)
 			return counter;
 		else
diff --git a/test/util/TestIntrusiveHashSet.cxx b/test/util/TestIntrusiveHashSet.cxx
index 4e2c6770e..69748fbb2 100644
--- a/test/util/TestIntrusiveHashSet.cxx
+++ b/test/util/TestIntrusiveHashSet.cxx
@@ -41,18 +41,18 @@ struct IntItem final : IntrusiveHashSetHook<IntrusiveHookMode::TRACK> {
 	IntItem(int _value) noexcept:value(_value) {}
 
 	struct Hash {
-		constexpr std::size_t operator()(const IntItem &i) noexcept {
+		constexpr std::size_t operator()(const IntItem &i) const noexcept {
 			return i.value;
 		}
 
-		constexpr std::size_t operator()(int i) noexcept {
+		constexpr std::size_t operator()(int i) const noexcept {
 			return i;
 		}
 	};
 
 	struct Equal {
 		constexpr bool operator()(const IntItem &a,
-					  const IntItem &b) noexcept {
+					  const IntItem &b) const noexcept {
 			return a.value == b.value;
 		}
 	};