From c7c5352325c39beb59a337d61e4734c84673d2ef Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Tue, 18 Feb 2020 19:20:24 +0100
Subject: [PATCH] Use a universal reference to implement dereferenceMaybe()

---
 misc/traits.h         | 16 ++--------------
 tests/traitstests.cpp |  5 +++--
 2 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/misc/traits.h b/misc/traits.h
index 9847d3d..fcb13c3 100644
--- a/misc/traits.h
+++ b/misc/traits.h
@@ -159,25 +159,13 @@ CPP_UTILITIES_TRAITS_DEFINE_TYPE_CHECK(IsIteratable,
         void(*begin(std::declval<T &>())));
 
 /// \brief Dereferences the specified \a value if possible; otherwise just returns \a value itself.
-template <typename T, EnableIf<IsDereferencable<T>> * = nullptr> constexpr auto &dereferenceMaybe(T &value)
+template <typename T, EnableIf<IsDereferencable<T>> * = nullptr> constexpr auto &dereferenceMaybe(T &&value)
 {
     return *value;
 }
 
 /// \brief Dereferences the specified \a value if possible; otherwise just returns \a value itself.
-template <typename T, DisableIf<IsDereferencable<T>> * = nullptr> constexpr auto &dereferenceMaybe(T &value)
-{
-    return value;
-}
-
-/// \brief Dereferences the specified \a value if possible; otherwise just returns \a value itself.
-template <typename T, EnableIf<IsDereferencable<T>> * = nullptr> constexpr const auto &dereferenceMaybe(const T &value)
-{
-    return *value;
-}
-
-/// \brief Dereferences the specified \a value if possible; otherwise just returns \a value itself.
-template <typename T, DisableIf<IsDereferencable<T>> * = nullptr> constexpr const auto &dereferenceMaybe(const T &value)
+template <typename T, DisableIf<IsDereferencable<T>> * = nullptr> constexpr auto &dereferenceMaybe(T &&value)
 {
     return value;
 }
diff --git a/tests/traitstests.cpp b/tests/traitstests.cpp
index df54713..158983b 100644
--- a/tests/traitstests.cpp
+++ b/tests/traitstests.cpp
@@ -133,8 +133,9 @@ CPPUNIT_TEST_SUITE_REGISTRATION(TraitsTest);
  */
 void TraitsTest::testDereferenceMaybe()
 {
-    const auto someString = "foo"s;
-    const auto someSmartPointer = make_unique<string>("foo");
+    auto someString = "foo"s;
+    auto someSmartPointer = make_unique<string>("foo");
     CPPUNIT_ASSERT_EQUAL("foo"s, dereferenceMaybe(someString));
     CPPUNIT_ASSERT_EQUAL("foo"s, dereferenceMaybe(someSmartPointer));
+    CPPUNIT_ASSERT_EQUAL("foo"s, dereferenceMaybe(make_unique<string>("foo")));
 }