From 443c22b1510e9a551a4e1a5173732d33e6f3eaca Mon Sep 17 00:00:00 2001
From: Quinton Miller <nicetas.c@gmail.com>
Date: Sat, 21 Nov 2020 00:21:26 +0800
Subject: [PATCH 1/2] Add wrapped unary negation to unsigned integer types

---
 spec/std/uint_spec.cr | 44 +++++++++++++++++++++++++++++++++++++++++++
 src/int.cr            | 21 +++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/spec/std/uint_spec.cr b/spec/std/uint_spec.cr
index 1634b377e20e..7de658f63b70 100644
--- a/spec/std/uint_spec.cr
+++ b/spec/std/uint_spec.cr
@@ -6,4 +6,48 @@ describe "UInt" do
     (0_u32 <=> 0_u32).should eq(0)
     (0_u32 <=> 1_u32).should eq(-1)
   end
+
+  describe "&-" do
+    it "returns the wrapped negation" do
+      x = &-0_u32
+      x.should eq(0_u32)
+      x.should be_a(UInt32)
+
+      x = &-100_u8
+      x.should eq(156_u8)
+      x.should be_a(UInt8)
+
+      x = &-1_u8
+      x.should eq(255_u8)
+      x.should be_a(UInt8)
+
+      x = &-255_u8
+      x.should eq(1_u8)
+      x.should be_a(UInt8)
+
+      x = &-1_u16
+      x.should eq(65535_u16)
+      x.should be_a(UInt16)
+
+      x = &-65535_u16
+      x.should eq(1_u16)
+      x.should be_a(UInt16)
+
+      x = &-1_u32
+      x.should eq(4294967295_u32)
+      x.should be_a(UInt32)
+
+      x = &-4294967295_u32
+      x.should eq(1_u32)
+      x.should be_a(UInt32)
+
+      x = &-1_u64
+      x.should eq(18446744073709551615_u64)
+      x.should be_a(UInt64)
+
+      x = &-18446744073709551615_u64
+      x.should eq(1_u64)
+      x.should be_a(UInt64)
+    end
+  end
 end
diff --git a/src/int.cr b/src/int.cr
index 87e868995f89..5c4fcc031b47 100644
--- a/src/int.cr
+++ b/src/int.cr
@@ -980,6 +980,10 @@ struct UInt8
   Number.expand_div [Float32], Float32
   Number.expand_div [Float64], Float64
 
+  def &-
+    0_u8 &- self
+  end
+
   def abs
     self
   end
@@ -1020,6 +1024,10 @@ struct UInt16
   Number.expand_div [Float32], Float32
   Number.expand_div [Float64], Float64
 
+  def &-
+    0_u16 &- self
+  end
+
   def abs
     self
   end
@@ -1060,6 +1068,10 @@ struct UInt32
   Number.expand_div [Float32], Float32
   Number.expand_div [Float64], Float64
 
+  def &-
+    0_u32 &- self
+  end
+
   def abs
     self
   end
@@ -1100,6 +1112,10 @@ struct UInt64
   Number.expand_div [Float32], Float32
   Number.expand_div [Float64], Float64
 
+  def &-
+    0_u64 &- self
+  end
+
   def abs
     self
   end
@@ -1141,6 +1157,11 @@ struct UInt128
   Number.expand_div [Float32], Float32
   Number.expand_div [Float64], Float64
 
+  def &-
+    # TODO: use 0_u128 - self
+    UInt128.new(0) &- self
+  end
+
   def abs
     self
   end

From fe9bffa08ab1c709fb87c27f97ecf1b185234fa7 Mon Sep 17 00:00:00 2001
From: Quinton Miller <nicetas.c@gmail.com>
Date: Sat, 21 Nov 2020 20:14:52 +0800
Subject: [PATCH 2/2] Update src/int.cr
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Co-authored-by: Johannes Müller <johannes.mueller@smj-fulda.org>
---
 src/int.cr | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/int.cr b/src/int.cr
index 5c4fcc031b47..359921e40f8e 100644
--- a/src/int.cr
+++ b/src/int.cr
@@ -1158,7 +1158,7 @@ struct UInt128
   Number.expand_div [Float64], Float64
 
   def &-
-    # TODO: use 0_u128 - self
+    # TODO: use 0_u128 &- self
     UInt128.new(0) &- self
   end