From 4f1c72c174c247f2d3c26c227ddd62bf6c0bf76c Mon Sep 17 00:00:00 2001
From: Michel Hermier <michel.hermier@gmail.com>
Date: Sat, 27 Mar 2021 22:12:07 +0100
Subject: [PATCH] AK: Add IsSigned conterpart to IsUnsigned.

---
 AK/StdLibExtras.h           | 4 ++++
 AK/Tests/TestTypeTraits.cpp | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/AK/StdLibExtras.h b/AK/StdLibExtras.h
index d4f282cda4..c46ad6e86d 100644
--- a/AK/StdLibExtras.h
+++ b/AK/StdLibExtras.h
@@ -546,6 +546,9 @@ using Void = void;
 template<typename... _Ignored>
 constexpr auto DependentFalse = false;
 
+template<typename T>
+using IsSigned = IsSame<T, typename MakeSigned<T>::Type>;
+
 template<typename T>
 using IsUnsigned = IsSame<T, typename MakeUnsigned<T>::Type>;
 
@@ -623,6 +626,7 @@ using AK::IsFundamental;
 using AK::IsIntegral;
 using AK::IsNullPointer;
 using AK::IsSame;
+using AK::IsSigned;
 using AK::IsUnion;
 using AK::IsUnsigned;
 using AK::IsVoid;
diff --git a/AK/Tests/TestTypeTraits.cpp b/AK/Tests/TestTypeTraits.cpp
index 2e1dbde4c5..1b13d71903 100644
--- a/AK/Tests/TestTypeTraits.cpp
+++ b/AK/Tests/TestTypeTraits.cpp
@@ -85,6 +85,14 @@ TEST_CASE(FundamentalTypeClassification)
 
     EXPECT_TRAIT_FALSE(IsFundamental, Empty, int*, int&);
 
+    EXPECT_TRAIT_FALSE(IsSigned, unsigned);
+    EXPECT_TRAIT_FALSE(IsSigned, unsigned short);
+    EXPECT_TRAIT_FALSE(IsSigned, unsigned char);
+    EXPECT_TRAIT_FALSE(IsSigned, unsigned long);
+    EXPECT_TRAIT_TRUE(IsSigned, int);
+    EXPECT_TRAIT_TRUE(IsSigned, short);
+    EXPECT_TRAIT_TRUE(IsSigned, long);
+
     EXPECT_TRAIT_TRUE(IsUnsigned, unsigned);
     EXPECT_TRAIT_TRUE(IsUnsigned, unsigned short);
     EXPECT_TRAIT_TRUE(IsUnsigned, unsigned char);