From 731844ee6d0f01fb8cff8601f29803a3f7bf8a1d Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Mon, 26 Nov 2018 10:00:17 -0300
Subject: [PATCH 1/5] Compiler: Refactor Enum due to overflow

If the last value was 1 << 31 an overflow would be thrown.
This is not changing the current behavior.
The Enum flags with UInt64 base type work only if the values are explicit.
---
 src/compiler/crystal/semantic/top_level_visitor.cr | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/compiler/crystal/semantic/top_level_visitor.cr b/src/compiler/crystal/semantic/top_level_visitor.cr
index 45c39b1e65e2..6c563cd9c5ed 100644
--- a/src/compiler/crystal/semantic/top_level_visitor.cr
+++ b/src/compiler/crystal/semantic/top_level_visitor.cr
@@ -676,10 +676,10 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
           if counter == 0 # In case the member is set to 0
             1
           else
-            counter * 2
+            counter &* 2
           end
         else
-          counter + 1
+          counter &+ 1
         end
       {new_counter, all_value}
     else

From e85bb7e32996423b8008e24c7dffb0910b0f450b Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Tue, 18 Dec 2018 17:42:33 -0300
Subject: [PATCH 2/5] Compiler: Use unchecked number conversions operations
 when calling libs

---
 spec/compiler/semantic/c_struct_spec.cr      | 12 ++++++------
 spec/compiler/semantic/lib_spec.cr           | 12 ++++++------
 src/compiler/crystal/semantic/conversions.cr |  2 +-
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/spec/compiler/semantic/c_struct_spec.cr b/spec/compiler/semantic/c_struct_spec.cr
index acb01cd722dd..0f3d15d47f9e 100644
--- a/spec/compiler/semantic/c_struct_spec.cr
+++ b/spec/compiler/semantic/c_struct_spec.cr
@@ -322,7 +322,7 @@ describe "Semantic: struct" do
       )) { int32 }
   end
 
-  it "errors if invoking to_i32 and got error in that call" do
+  it "errors if invoking to_i32! and got error in that call" do
     assert_error %(
       lib LibFoo
         struct Foo
@@ -331,7 +331,7 @@ describe "Semantic: struct" do
       end
 
       class Foo
-        def to_i32
+        def to_i32!
           1 + 'a'
         end
       end
@@ -339,10 +339,10 @@ describe "Semantic: struct" do
       foo = LibFoo::Foo.new
       foo.x = Foo.new
       ),
-      "converting from Foo to Int32 by invoking 'to_i32'"
+      "converting from Foo to Int32 by invoking 'to_i32!'"
   end
 
-  it "errors if invoking to_i32 and got wrong type" do
+  it "errors if invoking to_i32! and got wrong type" do
     assert_error %(
       lib LibFoo
         struct Foo
@@ -351,7 +351,7 @@ describe "Semantic: struct" do
       end
 
       class Foo
-        def to_i32
+        def to_i32!
           'a'
         end
       end
@@ -359,7 +359,7 @@ describe "Semantic: struct" do
       foo = LibFoo::Foo.new
       foo.x = Foo.new
       ),
-      "invoked 'to_i32' to convert from Foo to Int32, but got Char"
+      "invoked 'to_i32!' to convert from Foo to Int32, but got Char"
   end
 
   it "errors if invoking to_unsafe and got error in that call" do
diff --git a/spec/compiler/semantic/lib_spec.cr b/spec/compiler/semantic/lib_spec.cr
index 9fcbe9c97043..4b247bd3fd7e 100644
--- a/spec/compiler/semantic/lib_spec.cr
+++ b/spec/compiler/semantic/lib_spec.cr
@@ -608,38 +608,38 @@ describe "Semantic: lib" do
       )) { float64 }
   end
 
-  it "errors if invoking to_i32 and got error in that call" do
+  it "errors if invoking to_i32! and got error in that call" do
     assert_error %(
       lib LibFoo
         fun foo(x : Int32) : Float64
       end
 
       class Foo
-        def to_i32
+        def to_i32!
           1 + 'a'
         end
       end
 
       LibFoo.foo Foo.new
       ),
-      "converting from Foo to Int32 by invoking 'to_i32'"
+      "converting from Foo to Int32 by invoking 'to_i32!'"
   end
 
-  it "errors if invoking to_i32 and got wrong type" do
+  it "errors if invoking to_i32! and got wrong type" do
     assert_error %(
       lib LibFoo
         fun foo(x : Int32) : Float64
       end
 
       class Foo
-        def to_i32
+        def to_i32!
           'a'
         end
       end
 
       LibFoo.foo Foo.new
       ),
-      "invoked 'to_i32' to convert from Foo to Int32, but got Char"
+      "invoked 'to_i32!' to convert from Foo to Int32, but got Char"
   end
 
   it "defines lib funs before funs with body" do
diff --git a/src/compiler/crystal/semantic/conversions.cr b/src/compiler/crystal/semantic/conversions.cr
index 63161afd5200..e2998722ca98 100644
--- a/src/compiler/crystal/semantic/conversions.cr
+++ b/src/compiler/crystal/semantic/conversions.cr
@@ -1,6 +1,6 @@
 module Crystal::Conversions
   def self.numeric_argument(node, var, visitor, unaliased_type, expected_type, actual_type)
-    convert_call_name = "to_#{unaliased_type.kind}"
+    convert_call_name = "to_#{unaliased_type.kind}!"
     convert_call = Call.new(var, convert_call_name).at(node)
 
     begin

From 9253525feb8f89d3ed9a020735f8659dd33e0d85 Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Tue, 4 Dec 2018 01:00:32 -0300
Subject: [PATCH 3/5] Compiler: Refactor due to overflow

---
 src/compiler/crystal/semantic/lib.cr | 20 ++++++++++----------
 src/llvm/generic_value.cr            |  2 +-
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/compiler/crystal/semantic/lib.cr b/src/compiler/crystal/semantic/lib.cr
index 99b6c3bd25ea..e781c61983c8 100644
--- a/src/compiler/crystal/semantic/lib.cr
+++ b/src/compiler/crystal/semantic/lib.cr
@@ -244,16 +244,16 @@ class Crystal::Call
 
       self_arg.value =
         case unaliased_type
-        when program.uint8  ; num.to_u8.to_s
-        when program.uint16 ; num.to_u16.to_s
-        when program.uint32 ; num.to_u32.to_s
-        when program.uint64 ; num.to_u64.to_s
-        when program.int8   ; num.to_i8.to_s
-        when program.int16  ; num.to_i16.to_s
-        when program.int32  ; num.to_i32.to_s
-        when program.int64  ; num.to_i64.to_s
-        when program.float32; num.to_f32.to_s
-        else                  num.to_f64.to_s
+        when program.uint8  ; num.to_u8!.to_s
+        when program.uint16 ; num.to_u16!.to_s
+        when program.uint32 ; num.to_u32!.to_s
+        when program.uint64 ; num.to_u64!.to_s
+        when program.int8   ; num.to_i8!.to_s
+        when program.int16  ; num.to_i16!.to_s
+        when program.int32  ; num.to_i32!.to_s
+        when program.int64  ; num.to_i64!.to_s
+        when program.float32; num.to_f32!.to_s
+        else                  num.to_f64!.to_s
         end
       self_arg.kind = unaliased_type.kind
       self_arg.type = unaliased_type
diff --git a/src/llvm/generic_value.cr b/src/llvm/generic_value.cr
index e054e38dffd4..15f9d378c75e 100644
--- a/src/llvm/generic_value.cr
+++ b/src/llvm/generic_value.cr
@@ -3,7 +3,7 @@ class LLVM::GenericValue
   end
 
   def to_i : Int32
-    to_i64.to_i32
+    to_i64.to_i32!
   end
 
   def to_i64 : Int64

From d6904bfecd5073f0c95447e6280b74a2238eac11 Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Sun, 2 Dec 2018 19:11:42 -0300
Subject: [PATCH 4/5] Compiler: Handle Int128 UInt128 in IntegerType#range

---
 src/compiler/crystal/types.cr | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/compiler/crystal/types.cr b/src/compiler/crystal/types.cr
index 4dcdb04ef33c..c8ab4ff00c99 100644
--- a/src/compiler/crystal/types.cr
+++ b/src/compiler/crystal/types.cr
@@ -1282,6 +1282,8 @@ module Crystal
         {Int32::MIN, Int32::MAX}
       when :i64
         {Int64::MIN, Int64::MAX}
+      when :i128
+        {Int128::MIN, Int128::MAX}
       when :u8
         {UInt8::MIN, UInt8::MAX}
       when :u16
@@ -1290,6 +1292,8 @@ module Crystal
         {UInt32::MIN, UInt32::MAX}
       when :u64
         {UInt64::MIN, UInt64::MAX}
+      when :u128
+        {UInt128::MIN, UInt128::MAX}
       else
         raise "Bug: called 'range' for non-integer literal"
       end

From ff030b224be08a31d76f5d86591e5c827d9c732c Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Wed, 27 Jun 2018 10:49:02 +0200
Subject: [PATCH 5/5] Refactor Specs: Avoid using overflowing operators in
 codegen specs

Otherwise OverflowError and raise method will need to be defined
---
 spec/compiler/codegen/alias_spec.cr           |  2 +-
 spec/compiler/codegen/array_literal_spec.cr   | 16 ++---
 spec/compiler/codegen/block_spec.cr           | 48 ++++++++-------
 spec/compiler/codegen/c_struct_spec.cr        |  2 +-
 spec/compiler/codegen/class_spec.cr           |  2 +-
 spec/compiler/codegen/class_var_spec.cr       | 14 ++---
 spec/compiler/codegen/closure_spec.cr         | 40 ++++++-------
 spec/compiler/codegen/const_spec.cr           |  2 +-
 spec/compiler/codegen/def_spec.cr             | 18 +++---
 spec/compiler/codegen/double_splat_spec.cr    | 20 +++----
 spec/compiler/codegen/enum_spec.cr            |  4 +-
 spec/compiler/codegen/extern_spec.cr          | 34 +++++------
 spec/compiler/codegen/generic_class_spec.cr   |  6 +-
 spec/compiler/codegen/hash_literal_spec.cr    | 42 +++++++-------
 spec/compiler/codegen/hooks_spec.cr           |  4 +-
 spec/compiler/codegen/is_a_spec.cr            | 16 ++---
 spec/compiler/codegen/macro_spec.cr           | 58 ++++++++++---------
 spec/compiler/codegen/magic_constants_spec.cr |  4 +-
 spec/compiler/codegen/method_missing_spec.cr  | 14 ++---
 spec/compiler/codegen/module_spec.cr          |  4 +-
 spec/compiler/codegen/named_args_spec.cr      | 38 +++++++-----
 spec/compiler/codegen/named_tuple_spec.cr     |  2 +-
 spec/compiler/codegen/new_spec.cr             | 16 ++---
 spec/compiler/codegen/next_spec.cr            | 26 ++++-----
 spec/compiler/codegen/op_assign_spec.cr       | 10 ++--
 spec/compiler/codegen/pointer_spec.cr         |  4 +-
 spec/compiler/codegen/previous_def_spec.cr    |  6 +-
 spec/compiler/codegen/primitives_spec.cr      |  8 +--
 spec/compiler/codegen/proc_spec.cr            | 14 +++--
 spec/compiler/codegen/splat_spec.cr           | 16 ++---
 spec/compiler/codegen/ssa_spec.cr             |  4 +-
 spec/compiler/codegen/super_spec.cr           |  8 +--
 spec/compiler/codegen/tuple_spec.cr           |  4 +-
 spec/compiler/codegen/uninitialized_spec.cr   |  2 +-
 spec/compiler/codegen/union_type_spec.cr      | 14 ++++-
 spec/compiler/codegen/until_spec.cr           |  2 +-
 spec/compiler/codegen/var_spec.cr             |  4 +-
 spec/compiler/codegen/virtual_spec.cr         |  2 +-
 spec/compiler/codegen/while_spec.cr           | 10 ++--
 .../compiler/codegen/yield_with_scope_spec.cr |  6 +-
 40 files changed, 290 insertions(+), 256 deletions(-)

diff --git a/spec/compiler/codegen/alias_spec.cr b/spec/compiler/codegen/alias_spec.cr
index 3f595a4568ba..95048dcd9f6d 100644
--- a/spec/compiler/codegen/alias_spec.cr
+++ b/spec/compiler/codegen/alias_spec.cr
@@ -66,7 +66,7 @@ describe "Code gen: alias" do
         if n == 0
           1
         else
-          foo(n - 1).as(Foo)
+          foo(n &- 1).as(Foo)
         end
       end
 
diff --git a/spec/compiler/codegen/array_literal_spec.cr b/spec/compiler/codegen/array_literal_spec.cr
index a24fbc06d00e..e840a27d7b5b 100644
--- a/spec/compiler/codegen/array_literal_spec.cr
+++ b/spec/compiler/codegen/array_literal_spec.cr
@@ -9,7 +9,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -30,7 +30,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element : T)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -51,7 +51,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element : T)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -72,7 +72,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element : T)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -95,7 +95,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element : T)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -118,7 +118,7 @@ describe "Code gen: array literal spec" do
         end
 
         def <<(element)
-          @value += element
+          @value &+= element
         end
 
         def value
@@ -140,7 +140,7 @@ describe "Code gen: array literal spec" do
           end
 
           def <<(element)
-            @value += element
+            @value &+= element
           end
 
           def value
@@ -163,7 +163,7 @@ describe "Code gen: array literal spec" do
           end
 
           def <<(element : T)
-            @value += element
+            @value &+= element
           end
 
           def value
diff --git a/spec/compiler/codegen/block_spec.cr b/spec/compiler/codegen/block_spec.cr
index eb3e88cf25df..e82c3fb5b616 100644
--- a/spec/compiler/codegen/block_spec.cr
+++ b/spec/compiler/codegen/block_spec.cr
@@ -20,7 +20,7 @@ describe "Code gen: block" do
       end
 
       foo do |x|
-        x + 1
+        x &+ 1
       end
     ").to_i.should eq(2)
   end
@@ -32,7 +32,7 @@ describe "Code gen: block" do
       end
 
       foo(3) do |x|
-        x + 1
+        x &+ 1
       end
     ").to_i.should eq(4)
   end
@@ -46,7 +46,7 @@ describe "Code gen: block" do
       end
 
       3.foo do |x|
-        x + 1
+        x &+ 1
       end
     ").to_i.should eq(4)
   end
@@ -60,7 +60,7 @@ describe "Code gen: block" do
       end
 
       3.foo(2) do |x, i|
-        x + i
+        x &+ i
       end
     ").to_i.should eq(5)
   end
@@ -73,7 +73,7 @@ describe "Code gen: block" do
 
       x = 1
       foo do
-        x + 1
+        x &+ 1
       end
     ").to_i.should eq(2)
   end
@@ -90,7 +90,7 @@ describe "Code gen: block" do
       end
 
       Foo.new.foo do |x|
-        x + 1
+        x &+ 1
       end
     ").to_i.should eq(2)
   end
@@ -127,7 +127,7 @@ describe "Code gen: block" do
         end
       end
 
-      Foo.new.foo { |x| x + 1 }
+      Foo.new.foo { |x| x &+ 1 }
     ").to_i.should eq(2)
   end
 
@@ -320,6 +320,8 @@ describe "Code gen: block" do
 
   it "call block from dispatch and use local vars" do
     run("
+      require \"prelude\"
+
       def bar(y)
         yield y
       end
@@ -377,7 +379,7 @@ describe "Code gen: block" do
       end
 
       a = 0
-      foo { a += 1; break }
+      foo { a &+= 1; break }
       a
     ").to_i.should eq(1)
   end
@@ -445,7 +447,7 @@ describe "Code gen: block" do
       require \"nil\"
 
       def foo
-        1 + yield
+        1 &+ yield
       end
 
       foo { break 2 }.to_i
@@ -494,7 +496,7 @@ describe "Code gen: block" do
       end
 
       def foo
-        bar { 1 + yield }
+        bar { 1 &+ yield }
       end
 
       foo { break 3 }
@@ -906,6 +908,8 @@ describe "Code gen: block" do
 
   it "codegens dispatch with block and break (1)" do
     run("
+      require \"prelude\"
+
       class Foo(T)
         def initialize(@x : T)
         end
@@ -1021,7 +1025,7 @@ describe "Code gen: block" do
       end
 
       foo = Foo.new do |a|
-        a + 1
+        a &+ 1
       end
       foo.x
       )).to_i.should eq(2)
@@ -1135,7 +1139,7 @@ describe "Code gen: block" do
       foo do |key|
         if 1 == 1
           extra = 1
-          extra + key
+          extra &+ key
         end
       end
 
@@ -1201,7 +1205,7 @@ describe "Code gen: block" do
 
       a = 0
       foo do |x|
-        a += x
+        a &+= x
         next if true
         break
       end
@@ -1219,7 +1223,7 @@ describe "Code gen: block" do
 
       a = 0
       foo do |x|
-        a += x
+        a &+= x
         next if 1 == 1
         break
       end
@@ -1358,7 +1362,7 @@ describe "Code gen: block" do
 
       a = 0
       foo do |x|
-        a += x
+        a &+= x
       end
       a
       )).to_i.should eq(4)
@@ -1372,7 +1376,7 @@ describe "Code gen: block" do
       end
 
       foo do |x, y, z|
-        x + y + z
+        x &+ y &+ z
       end
       )).to_i.should eq(6)
   end
@@ -1396,7 +1400,7 @@ describe "Code gen: block" do
       end
 
       foo do |*args|
-        args[0] + args[1] + args[2]
+        args[0] &+ args[1] &+ args[2]
       end
       )).to_i.should eq(6)
   end
@@ -1408,7 +1412,7 @@ describe "Code gen: block" do
       end
 
       foo do |x, y, *z, w|
-        ((((x + y) * z[0]) - z[1]) * z[2]) - w
+        ((((x &+ y) &* z[0]) &- z[1]) &* z[2]) &- w
       end
       )).to_i.should eq(((((1 + 2) * 3) - 4) * 5) - 6)
   end
@@ -1422,7 +1426,7 @@ describe "Code gen: block" do
 
       total = 0
       foo do |*args|
-        total += args[0].to_i
+        total &+= args[0].to_i
       end
       total
       )).to_i.should eq(3)
@@ -1436,7 +1440,7 @@ describe "Code gen: block" do
       end
 
       foo do |x, y, z|
-        (x + y) * z
+        (x &+ y) &* z
       end
       )).to_i.should eq((1 + 2) * 4)
   end
@@ -1453,7 +1457,7 @@ describe "Code gen: block" do
       w = 4
       foo do |(x, y), (z, w)|
       end
-      x + y + z + w
+      x &+ y &+ z &+ w
       )).to_i.should eq(10)
   end
 
@@ -1506,7 +1510,7 @@ describe "Code gen: block" do
 
       a = fn(1 || 'a') { 2 }
       b = fn('a' || 1) { 2 }
-      a + b
+      a &+ b
       )).to_i.should eq(3)
   end
 
diff --git a/spec/compiler/codegen/c_struct_spec.cr b/spec/compiler/codegen/c_struct_spec.cr
index 626bbc235fff..4d93e967b3f5 100644
--- a/spec/compiler/codegen/c_struct_spec.cr
+++ b/spec/compiler/codegen/c_struct_spec.cr
@@ -261,7 +261,7 @@ describe "Code gen: struct" do
       end
 
       point = LibC::Point.new x: 1, y: 2
-      point.x + point.y
+      point.x &+ point.y
       )).to_i.should eq(3)
   end
 
diff --git a/spec/compiler/codegen/class_spec.cr b/spec/compiler/codegen/class_spec.cr
index da7ff1e7dcd5..b8504543f1e5 100644
--- a/spec/compiler/codegen/class_spec.cr
+++ b/spec/compiler/codegen/class_spec.cr
@@ -29,7 +29,7 @@ describe "Code gen: class" do
 
       f = Foo.new(2)
       g = Foo.new(40)
-      f.coco + g.coco
+      f.coco &+ g.coco
       ").to_i.should eq(42)
   end
 
diff --git a/spec/compiler/codegen/class_var_spec.cr b/spec/compiler/codegen/class_var_spec.cr
index 14be91036460..ae610e357070 100644
--- a/spec/compiler/codegen/class_var_spec.cr
+++ b/spec/compiler/codegen/class_var_spec.cr
@@ -110,7 +110,7 @@ describe "Codegen: class var" do
         @@var : Int32
         @@var = begin
           a = class_method
-          a + 3
+          a &+ 3
         end
 
         def self.var
@@ -118,7 +118,7 @@ describe "Codegen: class var" do
         end
 
         def self.class_method
-          1 + 2
+          1 &+ 2
         end
       end
 
@@ -130,7 +130,7 @@ describe "Codegen: class var" do
     run(%(
       class Foo
         @@var2 : Int32
-        @@var2 = @@var + 1
+        @@var2 = @@var &+ 1
 
         @@var = 41
 
@@ -199,7 +199,7 @@ describe "Codegen: class var" do
       def foo
         a = 1
         b = 2
-        a + b
+        a &+ b
       end
 
       CONST = foo()
@@ -256,7 +256,7 @@ describe "Codegen: class var" do
         @@foo = begin
           a = 1
           b = 2
-          a + b
+          a &+ b
         end
 
         def self.foo
@@ -274,7 +274,7 @@ describe "Codegen: class var" do
         @@foo : Int32 = begin
           a = 1
           b = 2
-          a + b
+          a &+ b
         end
 
         def self.foo
@@ -548,7 +548,7 @@ describe "Codegen: class var" do
       c = f2.bar
       f2.bar = 20
       d = f1.bar
-      a + b + c + d
+      a &+ b &+ c &+ d
       )).to_i.should eq(1 + 1 + 10 + 20)
   end
 end
diff --git a/spec/compiler/codegen/closure_spec.cr b/spec/compiler/codegen/closure_spec.cr
index 557f0054f161..b69c59ed75fe 100644
--- a/spec/compiler/codegen/closure_spec.cr
+++ b/spec/compiler/codegen/closure_spec.cr
@@ -54,7 +54,7 @@ describe "Code gen: closure" do
       a = 1
       f = foo do
         b = 2
-        -> { a + b }
+        -> { a &+ b }
       end
       f.call
     ").to_i.should eq(3)
@@ -70,7 +70,7 @@ describe "Code gen: closure" do
 
       a = 1
       f = foo do |x|
-        -> { a + x }
+        -> { a &+ x }
       end
       f.call
     ").to_i.should eq(4)
@@ -85,7 +85,7 @@ describe "Code gen: closure" do
 
       f = foo do |x|
         a = 2
-        -> { a + x }
+        -> { a &+ x }
       end
       f.call
       ").to_i.should eq(3)
@@ -118,7 +118,7 @@ describe "Code gen: closure" do
         b = 1
         foo do |y|
           c = 1
-          -> { a + b + c + x + y }
+          -> { a &+ b &+ c &+ x &+ y }
         end
       end
       f.call
@@ -153,7 +153,7 @@ describe "Code gen: closure" do
       f = foo do
         b = 1
         bar do
-          -> { a + b }
+          -> { a &+ b }
         end
       end
       f.call
@@ -175,7 +175,7 @@ describe "Code gen: closure" do
         b = 1
         bar do |x|
           x
-          -> { a + b }
+          -> { a &+ b }
         end
       end
       f.call
@@ -210,7 +210,7 @@ describe "Code gen: closure" do
 
         def foo
           a = 2
-          ->{ self.x + a }
+          ->{ self.x &+ a }
         end
 
         def x
@@ -230,7 +230,7 @@ describe "Code gen: closure" do
 
         def foo
           a = 2
-          ->{ x + a }
+          ->{ x &+ a }
         end
 
         def x
@@ -250,7 +250,7 @@ describe "Code gen: closure" do
 
         def foo
           a = 2
-          ->{ @x + a }
+          ->{ @x &+ a }
         end
       end
 
@@ -286,7 +286,7 @@ describe "Code gen: closure" do
         def foo
           bar do
             a = 2
-            ->{ @x + a }
+            ->{ @x &+ a }
           end
         end
       end
@@ -392,7 +392,7 @@ describe "Code gen: closure" do
       a = 1
       ->{
         b = 2
-        ->{ a + b }
+        ->{ a &+ b }
       }.call.call
       )).to_i.should eq(3)
   end
@@ -412,7 +412,7 @@ describe "Code gen: closure" do
               c = 3
               foo do |d|
                 -> {
-                  a + b + c + d
+                  a &+ b &+ c &+ d
                 }
               end
             }
@@ -453,7 +453,7 @@ describe "Code gen: closure" do
 
       a = 1
       f = ->(foo : Foo) {
-        foo.x + a
+        foo.x &+ a
       }
 
       obj = Foo.new(2)
@@ -468,7 +468,7 @@ describe "Code gen: closure" do
         end
 
         def foo(x)
-          @x + x
+          @x &+ x
         end
 
         def bar
@@ -500,7 +500,7 @@ describe "Code gen: closure" do
 
       a = 1
       foo do |x|
-        x + a
+        x &+ a
       end
       ").to_i.should eq(2)
   end
@@ -512,7 +512,7 @@ describe "Code gen: closure" do
       end
 
       a = 1
-      g = foo { |x| x + a }
+      g = foo { |x| x &+ a }
       h = foo { |x| x.to_f + a }
       (g.call(3) + h.call(5)).to_i
       ").to_i.should eq(10)
@@ -557,7 +557,7 @@ describe "Code gen: closure" do
       end
 
       a = 1
-      f = ->(x : Int32) { x + a }
+      f = ->(x : Int32) { x &+ a }
       foo &f
       ").to_i.should eq(2)
   end
@@ -570,7 +570,7 @@ describe "Code gen: closure" do
       end
 
       a = 0
-      foo { |x| a += x }
+      foo { |x| a &+= x }
       a
       )).to_i.should eq(3)
   end
@@ -670,7 +670,7 @@ describe "Code gen: closure" do
         # Here 'local' isn't to be confused with
         # the outer closured 'local'
         local = 1
-        local + arg
+        local &+ arg
       }
 
       arg = 2
@@ -678,7 +678,7 @@ describe "Code gen: closure" do
       local = 4_i64
       f2 = ->{ local.to_i }
 
-      f1.call + f2.call
+      f1.call &+ f2.call
     ))
   end
 end
diff --git a/spec/compiler/codegen/const_spec.cr b/spec/compiler/codegen/const_spec.cr
index e94e7af3aa41..8cf2b86a9b3f 100644
--- a/spec/compiler/codegen/const_spec.cr
+++ b/spec/compiler/codegen/const_spec.cr
@@ -288,7 +288,7 @@ describe "Codegen: const" do
       def foo
         a = 1
         b = 2
-        a + b
+        a &+ b
       end
 
       x
diff --git a/spec/compiler/codegen/def_spec.cr b/spec/compiler/codegen/def_spec.cr
index 2c2420fd8d73..c5ae5e5f0032 100644
--- a/spec/compiler/codegen/def_spec.cr
+++ b/spec/compiler/codegen/def_spec.cr
@@ -27,7 +27,7 @@ describe "Code gen: def" do
   end
 
   it "uses self" do
-    run("struct Int; def foo; self + 1; end; end; 3.foo").to_i.should eq(4)
+    run("struct Int; def foo; self &+ 1; end; end; 3.foo").to_i.should eq(4)
   end
 
   it "uses var after external" do
@@ -167,20 +167,20 @@ describe "Code gen: def" do
   it "codegens with and witout default arguments" do
     run("
       def foo(x = 1)
-        x + 1
+        x &+ 1
       end
 
-      foo(2) + foo
+      foo(2) &+ foo
       ").to_i.should eq(5)
   end
 
   it "codegens with and witout many default arguments" do
     run("
       def foo(x = 1, y = 2, z = 3)
-        x + y + z
+        x &+ y &+ z
       end
 
-      foo + foo(9) + foo(3, 4) + foo(6, 3, 1)
+      foo &+ foo(9) &+ foo(3, 4) &+ foo(6, 3, 1)
       ").to_i.should eq(40)
   end
 
@@ -188,7 +188,7 @@ describe "Code gen: def" do
     run("
       class Foo
         def foo(x = self.bar)
-          x + 1
+          x &+ 1
         end
 
         def bar
@@ -198,7 +198,7 @@ describe "Code gen: def" do
 
       f = Foo.new
 
-      f.foo(2) + f.foo
+      f.foo(2) &+ f.foo
       ").to_i.should eq(5)
   end
 
@@ -512,8 +512,8 @@ describe "Code gen: def" do
 
   it "uses previous argument in default value (#1062)" do
     run(%(
-      def foo(x = 123, y = x + 456)
-        x + y
+      def foo(x = 123, y = x &+ 456)
+        x &+ y
       end
 
       foo
diff --git a/spec/compiler/codegen/double_splat_spec.cr b/spec/compiler/codegen/double_splat_spec.cr
index 7dcc3a338a74..f7ffcf5d81f4 100644
--- a/spec/compiler/codegen/double_splat_spec.cr
+++ b/spec/compiler/codegen/double_splat_spec.cr
@@ -4,7 +4,7 @@ describe "Codegen: double splat" do
   it "double splats named argument into arguments (1)" do
     run(%(
       def foo(x, y)
-        x - y
+        x &- y
       end
 
       tup = {x: 32, y: 10}
@@ -15,7 +15,7 @@ describe "Codegen: double splat" do
   it "double splats named argument into arguments (2)" do
     run(%(
       def foo(x, y)
-        x - y
+        x &- y
       end
 
       tup = {y: 10, x: 32}
@@ -26,7 +26,7 @@ describe "Codegen: double splat" do
   it "double splats named argument with positional arguments" do
     run(%(
       def foo(x, y, z)
-        x - y*z
+        x &- y &* z
       end
 
       tup = {y: 20, z: 30}
@@ -37,7 +37,7 @@ describe "Codegen: double splat" do
   it "double splats named argument with named args (1)" do
     run(%(
       def foo(x, y, z)
-        x - y*z
+        x &- y &* z
       end
 
       tup = {x: 1000, z: 30}
@@ -48,7 +48,7 @@ describe "Codegen: double splat" do
   it "double splats named argument with named args (2)" do
     run(%(
       def foo(x, y, z)
-        x - y*z
+        x &- y &* z
       end
 
       tup = {z: 30}
@@ -59,7 +59,7 @@ describe "Codegen: double splat" do
   it "double splats twice " do
     run(%(
       def foo(x, y, z, w)
-        (x - y*z) * w
+        (x &- y &* z) &* w
       end
 
       tup1 = {x: 1000, z: 30}
@@ -71,7 +71,7 @@ describe "Codegen: double splat" do
   it "matches double splat on method with named args" do
     run(%(
       def foo(**options)
-        options[:x] - options[:y]
+        options[:x] &- options[:y]
       end
 
       foo x: 10, y: 3
@@ -81,7 +81,7 @@ describe "Codegen: double splat" do
   it "matches double splat on method with named args and regular args" do
     run(%(
       def foo(x, **args)
-        x - args[:y]*args[:z]
+        x &- args[:y] &* args[:z]
       end
 
       foo y: 20, z: 30, x: 1000
@@ -91,7 +91,7 @@ describe "Codegen: double splat" do
   it "matches double splat with regular splat" do
     run(%(
       def foo(*args, **options)
-        (args[0] - args[1]*options[:z]) * options[:w]
+        (args[0] &- args[1] &* options[:z]) &* options[:w]
       end
 
       foo 1000, 20, z: 30, w: 40
@@ -112,7 +112,7 @@ describe "Codegen: double splat" do
       end
 
       def data
-        Global.x += 1
+        Global.x &+= 1
         {x: Global.x, y: Global.x, z: Global.x}
       end
 
diff --git a/spec/compiler/codegen/enum_spec.cr b/spec/compiler/codegen/enum_spec.cr
index 95d77a416ace..97d8dc778381 100644
--- a/spec/compiler/codegen/enum_spec.cr
+++ b/spec/compiler/codegen/enum_spec.cr
@@ -317,8 +317,8 @@ describe "Code gen: enum" do
       end
 
       x = 0
-      x += 1 if Foo::None.none?
-      x += 2 if Foo::A.none?
+      x &+= 1 if Foo::None.none?
+      x &+= 2 if Foo::A.none?
       x
       )).to_i.should eq(1)
   end
diff --git a/spec/compiler/codegen/extern_spec.cr b/spec/compiler/codegen/extern_spec.cr
index 15dfc8640b9b..535358943e37 100644
--- a/spec/compiler/codegen/extern_spec.cr
+++ b/spec/compiler/codegen/extern_spec.cr
@@ -160,7 +160,7 @@ describe "Codegen: extern struct" do
       x = f.call(Data.new(1))
       y = f.call(Data.new(2))
 
-      x + y
+      x &+ y
       )).to_i.should eq(3)
   end
 
@@ -219,7 +219,7 @@ describe "Codegen: extern struct" do
               Global.y = s.y
             })
 
-            Global.x + Global.y
+            Global.x &+ Global.y
           ), &.to_i.should eq(3))
     end
 
@@ -270,11 +270,11 @@ describe "Codegen: extern struct" do
             end
 
             LibMylib.foo(->(x, s, y) {
-              Global.x = s.x + x
-              Global.y = s.y + y
+              Global.x = s.x &+ x
+              Global.y = s.y &+ y
             })
 
-            Global.x + Global.y
+            Global.x &+ Global.y
           ), &.to_i.should eq(33))
     end
 
@@ -330,7 +330,7 @@ describe "Codegen: extern struct" do
               nil
             })
 
-            Global.x + Global.y
+            Global.x &+ Global.y
           ), &.to_i.should eq(3))
     end
 
@@ -388,7 +388,7 @@ describe "Codegen: extern struct" do
               s
             })
 
-            Global.x + Global.y + s2.x + s2.y
+            Global.x &+ Global.y &+ s2.x &+ s2.y
           ), &.to_i.should eq(303))
     end
 
@@ -423,7 +423,7 @@ describe "Codegen: extern struct" do
               s
             })
 
-            s2.x + s2.y
+            s2.x &+ s2.y
           ), &.to_i.should eq(30))
     end
 
@@ -469,15 +469,15 @@ describe "Codegen: extern struct" do
             end
 
             s2 = LibMylib.foo(->(s) {
-              Global.x += s.x
-              Global.x += s.y
-              Global.x += s.z
+              Global.x &+= s.x
+              Global.x &+= s.y
+              Global.x &+= s.z
               s
             })
 
-            Global.x += s2.x
-            Global.x += s2.y
-            Global.x += s2.z
+            Global.x &+= s2.x
+            Global.x &+= s2.y
+            Global.x &+= s2.z
             Global.x.to_i32
           ), &.to_i.should eq(12))
     end
@@ -523,8 +523,8 @@ describe "Codegen: extern struct" do
           end
 
           f = ->(s : LibMylib::Struct) {
-            Global.x += s.x
-            Global.x += s.y
+            Global.x &+= s.x
+            Global.x &+= s.y
           }
 
           s = LibMylib::Struct.new
@@ -559,7 +559,7 @@ describe "Codegen: extern struct" do
           }
 
           s = f.call
-          s.x + s.y + s.z + s.w + s.a
+          s.x &+ s.y &+ s.z &+ s.w &+ s.a
           )).to_i.should eq(15)
     end
   {% end %}
diff --git a/spec/compiler/codegen/generic_class_spec.cr b/spec/compiler/codegen/generic_class_spec.cr
index f2afa7d0b7e1..7b68090379c3 100644
--- a/spec/compiler/codegen/generic_class_spec.cr
+++ b/spec/compiler/codegen/generic_class_spec.cr
@@ -8,7 +8,7 @@ describe "Code gen: generic class type" do
         end
 
         def x
-          @x + 1
+          @x &+ 1
         end
       end
 
@@ -30,7 +30,7 @@ describe "Code gen: generic class type" do
         end
       end
 
-      Foo(Int32).new.x + 1
+      Foo(Int32).new.x &+ 1
       )).to_i.should eq(2)
   end
 
@@ -150,7 +150,7 @@ describe "Code gen: generic class type" do
       end
 
       baz = Baz.new
-      baz.x + baz.y
+      baz.x &+ baz.y
       )).to_i.should eq(42)
   end
 
diff --git a/spec/compiler/codegen/hash_literal_spec.cr b/spec/compiler/codegen/hash_literal_spec.cr
index 34c8b664aa4d..b9e78077e551 100644
--- a/spec/compiler/codegen/hash_literal_spec.cr
+++ b/spec/compiler/codegen/hash_literal_spec.cr
@@ -10,8 +10,8 @@ describe "Code gen: hash literal spec" do
         end
 
         def []=(key, value)
-          @keys += key
-          @values += value
+          @keys &+= key
+          @values &+= value
         end
 
         def keys
@@ -24,7 +24,7 @@ describe "Code gen: hash literal spec" do
       end
 
       custom = Custom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -37,8 +37,8 @@ describe "Code gen: hash literal spec" do
         end
 
         def []=(key, value)
-          @keys += key
-          @values += value
+          @keys &+= key
+          @values &+= value
         end
 
         def keys
@@ -51,7 +51,7 @@ describe "Code gen: hash literal spec" do
       end
 
       custom = Custom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -64,8 +64,8 @@ describe "Code gen: hash literal spec" do
         end
 
         def []=(key, value)
-          @keys += key
-          @values += value
+          @keys &+= key
+          @values &+= value
         end
 
         def keys
@@ -78,7 +78,7 @@ describe "Code gen: hash literal spec" do
       end
 
       custom = Custom(Int32, Int32) {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -91,8 +91,8 @@ describe "Code gen: hash literal spec" do
         end
 
         def []=(key, value)
-          @keys += key
-          @values += value
+          @keys &+= key
+          @values &+= value
         end
 
         def keys
@@ -107,7 +107,7 @@ describe "Code gen: hash literal spec" do
       alias MyCustom = Custom
 
       custom = MyCustom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -120,8 +120,8 @@ describe "Code gen: hash literal spec" do
         end
 
         def []=(key, value)
-          @keys += key
-          @values += value
+          @keys &+= key
+          @values &+= value
         end
 
         def keys
@@ -136,7 +136,7 @@ describe "Code gen: hash literal spec" do
       alias MyCustom = Custom(Int32, Int32)
 
       custom = MyCustom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -163,8 +163,8 @@ describe "Code gen: hash literal spec" do
           end
 
           def []=(key, value)
-            @keys += key
-            @values += value
+            @keys &+= key
+            @values &+= value
           end
 
           def keys
@@ -178,7 +178,7 @@ describe "Code gen: hash literal spec" do
       end
 
       custom = Moo::Custom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 
@@ -192,8 +192,8 @@ describe "Code gen: hash literal spec" do
           end
 
           def []=(key, value)
-            @keys += key
-            @values += value
+            @keys &+= key
+            @values &+= value
           end
 
           def keys
@@ -207,7 +207,7 @@ describe "Code gen: hash literal spec" do
       end
 
       custom = Moo::Custom {1 => 10, 2 => 20}
-      custom.keys * custom.values
+      custom.keys &* custom.values
       )).to_i.should eq(90)
   end
 end
diff --git a/spec/compiler/codegen/hooks_spec.cr b/spec/compiler/codegen/hooks_spec.cr
index 7b480167962b..eb745bb5d320 100644
--- a/spec/compiler/codegen/hooks_spec.cr
+++ b/spec/compiler/codegen/hooks_spec.cr
@@ -100,7 +100,7 @@ describe "Code gen: hooks" do
 
       class Foo
         macro inherited
-          Global.x += 1
+          Global.x &+= 1
         end
       end
 
@@ -138,7 +138,7 @@ describe "Code gen: hooks" do
       end
 
       class Bar < Foo
-        Global.x += 1
+        Global.x &+= 1
       end
 
       Bar.y
diff --git a/spec/compiler/codegen/is_a_spec.cr b/spec/compiler/codegen/is_a_spec.cr
index d07b1f7ccbbf..346567d5402b 100644
--- a/spec/compiler/codegen/is_a_spec.cr
+++ b/spec/compiler/codegen/is_a_spec.cr
@@ -243,7 +243,7 @@ describe "Codegen: is_a?" do
     run("
       a = 1
       if a.is_a?(Int32 | Char)
-        a + 1
+        a &+ 1
       else
         0
       end
@@ -253,7 +253,7 @@ describe "Codegen: is_a?" do
   it "restricts union with union" do
     run("
       struct Char
-        def +(other : Int32)
+        def &+(other : Int32)
           other
         end
       end
@@ -266,7 +266,7 @@ describe "Codegen: is_a?" do
 
       a = 1 || 'a' || false
       if a.is_a?(Int32 | Char)
-        a + 2
+        a &+ 2
       else
         a.foo
       end
@@ -433,7 +433,7 @@ describe "Codegen: is_a?" do
       foo = Foo.new(1)
       x = foo.x
       if x.is_a?(Int32)
-        z = x + 1
+        z = x &+ 1
       else
         z = x.foo_bar
       end
@@ -513,7 +513,7 @@ describe "Codegen: is_a?" do
     run(%(
       a = 123
       if (b = a).is_a?(Int32)
-        b + 1
+        b &+ 1
       else
         a
       end
@@ -524,7 +524,7 @@ describe "Codegen: is_a?" do
     run(%(
       a = 123
       if (b = a).is_a?(Int32)
-        a + 2
+        a &+ 2
       else
         b
       end
@@ -537,7 +537,7 @@ describe "Codegen: is_a?" do
       if (b = a).is_a?(Char)
         b
       else
-        b + 1
+        b &+ 1
       end
       )).to_i.should eq(124)
   end
@@ -550,7 +550,7 @@ describe "Codegen: is_a?" do
       else
         a
       end
-      b ? b + 1 : 0
+      b ? b &+ 1 : 0
       )).to_i.should eq(124)
   end
 
diff --git a/spec/compiler/codegen/macro_spec.cr b/spec/compiler/codegen/macro_spec.cr
index 5ed9184b9184..c6b22b1af023 100644
--- a/spec/compiler/codegen/macro_spec.cr
+++ b/spec/compiler/codegen/macro_spec.cr
@@ -2,13 +2,13 @@ require "../../spec_helper"
 
 describe "Code gen: macro" do
   it "expands macro" do
-    run("macro foo; 1 + 2; end; foo").to_i.should eq(3)
+    run("macro foo; 1 &+ 2; end; foo").to_i.should eq(3)
   end
 
   it "expands macro with arguments" do
     run(%(
       macro foo(n)
-        {{n}} + 2
+        {{n}} &+ 2
       end
 
       foo(1)
@@ -19,7 +19,7 @@ describe "Code gen: macro" do
     run(%(
       macro foo
         def x
-          1 + 2
+          1 &+ 2
         end
       end
 
@@ -79,7 +79,7 @@ describe "Code gen: macro" do
     run(%(
       a = 0
       {% for i in [1, 2, 3] %}
-        a += {{i}}
+        a &+= {{i}}
       {% end %}
       a
       )).to_i.should eq(6)
@@ -89,7 +89,7 @@ describe "Code gen: macro" do
     run(%(
       a = 0
       {% if 1 == 1 %}
-        a += 1
+        a &+= 1
       {% end %}
       a
       )).to_i.should eq(1)
@@ -99,7 +99,7 @@ describe "Code gen: macro" do
     run(%(
       a = 0
       {% if 1 == 2 %}
-        a += 1
+        a &+= 1
       {% end %}
       a
       )).to_i.should eq(0)
@@ -109,7 +109,7 @@ describe "Code gen: macro" do
     run(%(
       class Foo
         macro foo
-          1 + 2
+          1 &+ 2
         end
 
         def bar
@@ -323,7 +323,7 @@ describe "Code gen: macro" do
       end
 
       macro foo(x, y = :bar)
-        {{x}} + {{y.id}}
+        {{x}} &+ {{y.id}}
       end
 
       foo(1)
@@ -425,9 +425,15 @@ describe "Code gen: macro" do
 
   it "doesn't reuse macro nodes (bug)" do
     run(%(
+      struct Float
+        def &+(other)
+          self + other
+        end
+      end
+
       def foo(x)
         {% for y in [1, 2] %}
-          x + 1
+          x &+ 1
         {% end %}
       end
 
@@ -490,7 +496,7 @@ describe "Code gen: macro" do
 
       a = 0
       foo do |x|
-        a += x
+        a &+= x
       end
       a
       )).to_i.should eq(3)
@@ -617,7 +623,7 @@ describe "Code gen: macro" do
       end
 
       foo do |x|
-        x + 1
+        x &+ 1
       end
       )).to_i.should eq(2)
   end
@@ -625,7 +631,7 @@ describe "Code gen: macro" do
   it "executes with named arguments" do
     run(%(
       macro foo(x = 1)
-        {{x}} + 1
+        {{x}} &+ 1
       end
 
       foo x: 2
@@ -735,7 +741,7 @@ describe "Code gen: macro" do
         end
       end
 
-      Color.red.value + Color.green.value + Color.blue.value
+      Color.red.value &+ Color.green.value &+ Color.blue.value
       )).to_i.should eq(0 + 1 + 2)
   end
 
@@ -927,14 +933,14 @@ describe "Code gen: macro" do
   it "doesn't override local variable when using macro variable (2)" do
     run(%(
       macro foo(x)
-        %a = {{x}} + 10
+        %a = {{x}} &+ 10
         %a
       end
 
       a = 1
       z = foo(2)
       w = foo(3)
-      a + z + w
+      a &+ z &+ w
       )).to_i.should eq(26)
   end
 
@@ -947,14 +953,14 @@ describe "Code gen: macro" do
 
         %total = 0
         {% for elem, i in elems %}
-          %total += %var{i}
+          %total &+= %var{i}
         {% end %}
         %total
       end
 
       z = 0
-      z += foo 4, 5, 6
-      z += foo 40, 50, 60
+      z &+= foo 4, 5, 6
+      z &+= foo 40, 50, 60
       z
       )).to_i.should eq(4 + 5 + 6 + 40 + 50 + 60)
   end
@@ -968,7 +974,7 @@ describe "Code gen: macro" do
 
         %total = 0
         {% for elem, i in elems %}
-          %total += %var{elem, i}
+          %total &+= %var{elem, i}
         {% end %}
         %total
       end
@@ -983,7 +989,7 @@ describe "Code gen: macro" do
       class Foo
         def bar(*args) : Int32
           {{ @type }}
-          args[0] + args[1] + args[2]
+          args[0] &+ args[1] &+ args[2]
         end
       end
 
@@ -996,7 +1002,7 @@ describe "Code gen: macro" do
       class Foo
         def bar(foo = 1) : Int32
           {{ @type }}
-          foo + 2
+          foo &+ 2
         end
       end
 
@@ -1302,7 +1308,7 @@ describe "Code gen: macro" do
   it "executes with named arguments for positional arg (1)" do
     run(%(
       macro foo(x)
-        {{x}} + 1
+        {{x}} &+ 1
       end
 
       foo x: 2
@@ -1312,7 +1318,7 @@ describe "Code gen: macro" do
   it "executes with named arguments for positional arg (2)" do
     run(%(
       macro foo(x, y)
-        {{x}} + {{y}} + 1
+        {{x}} &+ {{y}} &+ 1
       end
 
       foo x: 2, y: 3
@@ -1328,7 +1334,7 @@ describe "Code gen: macro" do
       end
 
       macro foo(x, y)
-        {{x}} + {{y}}.bytesize + 1
+        {{x}} &+ {{y}}.bytesize &+ 1
       end
 
       foo y: "foo", x: 2
@@ -1789,8 +1795,8 @@ describe "Code gen: macro" do
 
       x, y = Foo.new(2).defaults
       a = 0
-      a += 1 if x
-      a += 2 if y
+      a &+= 1 if x
+      a &+= 2 if y
       a
     )).to_i.should eq(1)
   end
diff --git a/spec/compiler/codegen/magic_constants_spec.cr b/spec/compiler/codegen/magic_constants_spec.cr
index 35b8885df6c1..edf1d9d9aeff 100644
--- a/spec/compiler/codegen/magic_constants_spec.cr
+++ b/spec/compiler/codegen/magic_constants_spec.cr
@@ -61,7 +61,7 @@ describe "Code gen: magic constants" do
       require "primitives"
 
       def foo(x, z = 10, line = __LINE__)
-        z + line
+        z &+ line
       end
 
       foo 1, 20
@@ -73,7 +73,7 @@ describe "Code gen: magic constants" do
       require "primitives"
 
       def foo(x, line = __LINE__, z = 1)
-        z + line
+        z &+ line
       end
 
       foo 1, z: 20
diff --git a/spec/compiler/codegen/method_missing_spec.cr b/spec/compiler/codegen/method_missing_spec.cr
index 00a6c4a53f67..d2cb16a0b34c 100644
--- a/spec/compiler/codegen/method_missing_spec.cr
+++ b/spec/compiler/codegen/method_missing_spec.cr
@@ -21,7 +21,7 @@ describe "Code gen: method_missing" do
     run(%(
       class Foo
         macro method_missing(call)
-          {{call.args.join(" + ").id}}
+          {{call.args.join(" &+ ").id}}
         end
       end
 
@@ -45,7 +45,7 @@ describe "Code gen: method_missing" do
 
       a = 0
       Foo.new.foo do |x|
-        a += x
+        a &+= x
       end
       a
       )).to_i.should eq(6)
@@ -55,7 +55,7 @@ describe "Code gen: method_missing" do
     run(%(
       class Foo
         def foo_something
-          1 + 2
+          1 &+ 2
         end
 
         macro method_missing(call)
@@ -339,7 +339,7 @@ describe "Code gen: method_missing" do
     run(%(
       class Foo
         macro method_missing(call)
-          {{call.args.join(" + ").id}}
+          {{call.args.join(" &+ ").id}}
         end
       end
 
@@ -351,7 +351,7 @@ describe "Code gen: method_missing" do
     run(%(
       class Wrapped
         def foo(x, y, z)
-          x + y + z
+          x &+ y &+ z
         end
       end
 
@@ -386,7 +386,7 @@ describe "Code gen: method_missing" do
     run(%(
       class A
         macro method_missing(call)
-          x + y
+          x &+ y
         end
       end
 
@@ -399,7 +399,7 @@ describe "Code gen: method_missing" do
     run(%(
       class A
         macro method_missing(call)
-          {{call.named_args[0].name}} +
+          {{call.named_args[0].name}} &+
             {{call.named_args[1].name}}
         end
       end
diff --git a/spec/compiler/codegen/module_spec.cr b/spec/compiler/codegen/module_spec.cr
index 49946f8ac8c6..36f8d72b1684 100644
--- a/spec/compiler/codegen/module_spec.cr
+++ b/spec/compiler/codegen/module_spec.cr
@@ -488,7 +488,7 @@ describe "Code gen: module" do
       mooer = Mooer.new(Bar.new)
       y = mooer.moo
 
-      x + y
+      x &+ y
       )).to_i.should eq(3)
   end
 
@@ -527,7 +527,7 @@ describe "Code gen: module" do
       mooer = Mooer.new(Bar(Int32).new)
       y = mooer.moo
 
-      x + y
+      x &+ y
       )).to_i.should eq(3)
   end
 
diff --git a/spec/compiler/codegen/named_args_spec.cr b/spec/compiler/codegen/named_args_spec.cr
index 2ef815f6e968..87f8424464cd 100644
--- a/spec/compiler/codegen/named_args_spec.cr
+++ b/spec/compiler/codegen/named_args_spec.cr
@@ -14,7 +14,7 @@ describe "Code gen: named args" do
   it "calls with named arg and other args" do
     run(%(
       def foo(x, y = 2, z = 3)
-        x + y + z
+        x &+ y &+ z
       end
 
       foo 1, z: 10
@@ -25,7 +25,7 @@ describe "Code gen: named args" do
     run(%(
       class Foo
         def foo(x, y = 2, z = 3)
-          x + y + z
+          x &+ y &+ z
         end
       end
 
@@ -35,13 +35,19 @@ describe "Code gen: named args" do
 
   it "calls twice with different types" do
     run(%(
+      struct Int32
+        def &+(other : Float)
+          self + other
+        end
+      end
+
       def add(x, y = 1)
-        x + y
+        x &+ y
       end
 
       value = 0
-      value += add(1, y: 2)
-      value += add(1, y: 1.3)
+      value &+= add(1, y: 2)
+      value &+= add(1, y: 1.3)
       value.to_i
       )).to_i.should eq(5)
   end
@@ -52,7 +58,7 @@ describe "Code gen: named args" do
         @value : Int32
 
         def initialize(x, y = 2, z = 3)
-          @value = x + y + z
+          @value = x &+ y &+ z
         end
 
         def value
@@ -68,13 +74,13 @@ describe "Code gen: named args" do
     run(%(
       class Foo
         def foo(x, z = 2)
-          x + z + 1
+          x &+ z &+ 1
         end
       end
 
       class Bar
         def foo(x, z = 2)
-          x + z
+          x &+ z
         end
       end
 
@@ -96,7 +102,7 @@ describe "Code gen: named args" do
   it "sends two regular arguments as named arguments" do
     run(%(
       def foo(x, y)
-        x + y
+        x &+ y
       end
 
       foo x: 10, y: 32
@@ -126,32 +132,32 @@ describe "Code gen: named args" do
   it "overloads based on required named args" do
     run(%(
       def foo(x, *, y)
-        x + y
+        x &+ y
       end
 
       def foo(x, *, z)
-        x * z
+        x &* z
       end
 
       a = foo(10, y: 20)
       b = foo(30, z: 40)
-      a + b
+      a &+ b
       )).to_i.should eq(10 + 20 + 30*40)
   end
 
   it "overloads based on required named args, with restrictions" do
     run(%(
       def foo(x, *, z : Int32)
-        x + z
+        x &+ z
       end
 
       def foo(x, *, z : Float64)
-        x * z.to_i
+        x &* z.to_i
       end
 
       a = foo(10, z: 20)
       b = foo(30, z: 40.0)
-      a + b
+      a &+ b
       )).to_i.should eq(10 + 20 + 30*40)
   end
 
@@ -169,7 +175,7 @@ describe "Code gen: named args" do
 
       v1 = Foo.new.y
       v2 = Foo.new(y: 20).y
-      v1 + v2
+      v1 &+ v2
       )).to_i.should eq(42)
   end
 end
diff --git a/spec/compiler/codegen/named_tuple_spec.cr b/spec/compiler/codegen/named_tuple_spec.cr
index b581e70bfe7b..18a7d5f2d902 100644
--- a/spec/compiler/codegen/named_tuple_spec.cr
+++ b/spec/compiler/codegen/named_tuple_spec.cr
@@ -273,7 +273,7 @@ describe "Code gen: named tuple" do
       if v.is_a?(Float64)
         10
       else
-        v[0].to_i + v[1].to_i
+        v[0].to_i &+ v[1].to_i
       end
       )).to_i.should eq(42)
   end
diff --git a/spec/compiler/codegen/new_spec.cr b/spec/compiler/codegen/new_spec.cr
index 5185fbba07f3..bb04c5cbb80f 100644
--- a/spec/compiler/codegen/new_spec.cr
+++ b/spec/compiler/codegen/new_spec.cr
@@ -133,7 +133,7 @@ describe "Code gen: new" do
 
       class Bar < Foo
         def self.new(foo : Int32) : self
-          Global.x = foo + 1
+          Global.x = foo &+ 1
           super
         end
       end
@@ -162,7 +162,7 @@ describe "Code gen: new" do
         end
 
         def self.new(foo : Int32) : self
-          Global.x = foo + 1
+          Global.x = foo &+ 1
           previous_def
         end
       end
@@ -179,7 +179,7 @@ describe "Code gen: new" do
         @x : Int32
 
         def initialize(x : Int32)
-          @x = x + 1
+          @x = x &+ 1
         end
 
         def x
@@ -325,7 +325,7 @@ describe "Code gen: new" do
       end
 
       foo = Foo.new(y: 22)
-      foo.x + foo.y
+      foo.x &+ foo.y
       )).to_i.should eq(42)
   end
 
@@ -349,10 +349,10 @@ describe "Code gen: new" do
 
       total = 0
       foo = Foo.new do |a, b|
-        total += a
-        total += b
+        total &+= a
+        total &+= b
       end
-      total += foo.x
+      total &+= foo.x
       total
       )).to_i.should eq(42)
   end
@@ -381,7 +381,7 @@ describe "Code gen: new" do
       foo = Foo.new do
         20
       end
-      foo.x + foo.block.call
+      foo.x &+ foo.block.call
       )).to_i.should eq(42)
   end
 end
diff --git a/spec/compiler/codegen/next_spec.cr b/spec/compiler/codegen/next_spec.cr
index 55c9153d2539..bcb397996f12 100644
--- a/spec/compiler/codegen/next_spec.cr
+++ b/spec/compiler/codegen/next_spec.cr
@@ -25,7 +25,7 @@ describe "Code gen: next" do
       a = 0
       foo do |i|
         next if i.unsafe_mod(2) == 0
-        a += i
+        a &+= i
       end
       a
       ").to_i.should eq(4)
@@ -35,10 +35,10 @@ describe "Code gen: next" do
     run("
       def foo
         x = 0
-        x += yield 1
-        x += yield 2
-        x += yield 3
-        x += yield 4
+        x &+= yield 1
+        x &+= yield 2
+        x &+= yield 3
+        x &+= yield 4
         x
       end
 
@@ -75,8 +75,8 @@ describe "Code gen: next" do
     run("
       def foo
         a = 0
-        a += yield 1
-        a += yield 2
+        a &+= yield 1
+        a &+= yield 2
         a
       end
 
@@ -95,8 +95,8 @@ describe "Code gen: next" do
     run("
       def foo
         a = 0
-        a += yield 1
-        a += yield 2
+        a &+= yield 1
+        a &+= yield 2
         a
       end
 
@@ -115,8 +115,8 @@ describe "Code gen: next" do
     run("
       def foo
         a = 0
-        a += yield 4
-        a += yield 5
+        a &+= yield 4
+        a &+= yield 5
         a
       end
 
@@ -124,9 +124,9 @@ describe "Code gen: next" do
         a = 0
         b = 0
         while a < 4
-          a += 1
+          a &+= 1
           next if a.unsafe_mod(2) == 0
-          b += a
+          b &+= a
         end
         if b == i
           next 10
diff --git a/spec/compiler/codegen/op_assign_spec.cr b/spec/compiler/codegen/op_assign_spec.cr
index 0d3983aeba8c..5a6127efaa4f 100644
--- a/spec/compiler/codegen/op_assign_spec.cr
+++ b/spec/compiler/codegen/op_assign_spec.cr
@@ -24,11 +24,11 @@ describe "Code gen: op assign" do
       end
 
       def foo
-        Global.value += 1
+        Global.value &+= 1
         Foo.new
       end
 
-      foo.bar += 2
+      foo.bar &+= 2
 
       Global.value
       )).to_i.should eq(1)
@@ -57,16 +57,16 @@ describe "Code gen: op assign" do
       end
 
       def foo
-        Global.value += 1
+        Global.value &+= 1
         Foo.new
       end
 
       def bar
-        Global.value += 10
+        Global.value &+= 10
         0
       end
 
-      foo[bar] += 2
+      foo[bar] &+= 2
 
       Global.value
       )).to_i.should eq(11)
diff --git a/spec/compiler/codegen/pointer_spec.cr b/spec/compiler/codegen/pointer_spec.cr
index 2162bef09149..1c398324f177 100644
--- a/spec/compiler/codegen/pointer_spec.cr
+++ b/spec/compiler/codegen/pointer_spec.cr
@@ -53,11 +53,11 @@ describe "Code gen: pointer" do
   end
 
   it "codegens malloc" do
-    run("p = Pointer(Int32).malloc(10_u64); p.value = 1; p.value + 1_i64").to_i.should eq(2)
+    run("p = Pointer(Int32).malloc(10_u64); p.value = 1; p.value &+ 1_i64").to_i.should eq(2)
   end
 
   it "codegens realloc" do
-    run("p = Pointer(Int32).malloc(10_u64); p.value = 1; x = p.realloc(20_u64); x.value + 1_i64").to_i.should eq(2)
+    run("p = Pointer(Int32).malloc(10_u64); p.value = 1; x = p.realloc(20_u64); x.value &+ 1_i64").to_i.should eq(2)
   end
 
   it "codegens pointer cast" do
diff --git a/spec/compiler/codegen/previous_def_spec.cr b/spec/compiler/codegen/previous_def_spec.cr
index 9981cff28254..444a1b30f42a 100644
--- a/spec/compiler/codegen/previous_def_spec.cr
+++ b/spec/compiler/codegen/previous_def_spec.cr
@@ -8,7 +8,7 @@ describe "codegen: previous_def" do
       end
 
       def foo
-        previous_def + 1
+        previous_def &+ 1
       end
 
       foo
@@ -18,11 +18,11 @@ describe "codegen: previous_def" do
   it "codeges previous def when inside fun and forwards args" do
     run(%(
       def foo(z)
-        z + 1
+        z &+ 1
       end
 
       def foo(z)
-        ->(x : Int32) { x + previous_def }
+        ->(x : Int32) { x &+ previous_def }
       end
 
       x = foo(2)
diff --git a/spec/compiler/codegen/primitives_spec.cr b/spec/compiler/codegen/primitives_spec.cr
index 21cbca7b7fdf..ccb96c55acea 100644
--- a/spec/compiler/codegen/primitives_spec.cr
+++ b/spec/compiler/codegen/primitives_spec.cr
@@ -55,7 +55,7 @@ describe "Code gen: primitives" do
   end
 
   it "codegens 1 + 2" do
-    run(%(1 + 2)).to_i.should eq(3)
+    run(%(require "prelude"; 1 + 2)).to_i.should eq(3)
   end
 
   it "codegens 1 &+ 2" do
@@ -63,7 +63,7 @@ describe "Code gen: primitives" do
   end
 
   it "codegens 1 - 2" do
-    run(%(1 - 2)).to_i.should eq(-1)
+    run(%(require "prelude"; 1 - 2)).to_i.should eq(-1)
   end
 
   it "codegens 1 &- 2" do
@@ -71,7 +71,7 @@ describe "Code gen: primitives" do
   end
 
   it "codegens 2 * 3" do
-    run(%(2 * 3)).to_i.should eq(6)
+    run(%(require "prelude"; 2 * 3)).to_i.should eq(6)
   end
 
   it "codegens 2 &* 3" do
@@ -178,7 +178,7 @@ describe "Code gen: primitives" do
         fun foo : K
       end
 
-      Test.foo + 1
+      Test.foo &+ 1
       ))
   end
 
diff --git a/spec/compiler/codegen/proc_spec.cr b/spec/compiler/codegen/proc_spec.cr
index 784f05ab2bee..f513e9b97649 100644
--- a/spec/compiler/codegen/proc_spec.cr
+++ b/spec/compiler/codegen/proc_spec.cr
@@ -6,7 +6,7 @@ describe "Code gen: proc" do
   end
 
   it "call proc literal with arguments" do
-    run("f = ->(x : Int32) { x + 1 }; f.call(41)").to_i.should eq(42)
+    run("f = ->(x : Int32) { x &+ 1 }; f.call(41)").to_i.should eq(42)
   end
 
   it "call proc pointer" do
@@ -16,7 +16,7 @@ describe "Code gen: proc" do
   it "call proc pointer with args" do
     run("
       def foo(x, y)
-        x + y
+        x &+ y
       end
 
       f = ->foo(Int32, Int32)
@@ -87,7 +87,13 @@ describe "Code gen: proc" do
 
   it "codegens proc that accepts a union and is called with a single type" do
     run("
-      f = ->(x : Int32 | Float64) { x + 1 }
+      struct Float
+        def &+(other)
+          self + other
+        end
+      end
+
+      f = ->(x : Int32 | Float64) { x &+ 1 }
       f.call(1).to_i
       ").to_i.should eq(2)
   end
@@ -390,7 +396,7 @@ describe "Code gen: proc" do
       alias Func = Int32 -> Int32
 
       a = 2
-      f = Func.new { |x| x + a }
+      f = Func.new { |x| x &+ a }
       f.call(1)
       ").to_i.should eq(3)
   end
diff --git a/spec/compiler/codegen/splat_spec.cr b/spec/compiler/codegen/splat_spec.cr
index 0d149a73fa69..8ac1f3955d5e 100644
--- a/spec/compiler/codegen/splat_spec.cr
+++ b/spec/compiler/codegen/splat_spec.cr
@@ -22,7 +22,7 @@ describe "Code gen: splat" do
       end
 
       def foo(x, *args)
-        x + args.size
+        x &+ args.size
       end
 
       foo 10, 1, 1
@@ -32,7 +32,7 @@ describe "Code gen: splat" do
   it "splats on call" do
     run(%(
       def foo(x, y)
-        x + y
+        x &+ y
       end
 
       tuple = {1, 2}
@@ -61,7 +61,7 @@ describe "Code gen: splat" do
       end
 
       def foo(x = 100, *args)
-        x + args.size
+        x &+ args.size
       end
 
       foo
@@ -75,7 +75,7 @@ describe "Code gen: splat" do
       end
 
       def foo(x, y = 100, *args)
-        x + y + args.size
+        x &+ y &+ args.size
       end
 
       foo 10
@@ -89,7 +89,7 @@ describe "Code gen: splat" do
       end
 
       def foo(x, y = 100, *args)
-        x + y + args.size
+        x &+ y &+ args.size
       end
 
       foo 10, 20, 30, 40
@@ -116,7 +116,7 @@ describe "Code gen: splat" do
       end
 
       foo = Foo.new 1, 2
-      foo.x + foo.y
+      foo.x &+ foo.y
       )).to_i.should eq(3)
   end
 
@@ -157,12 +157,12 @@ describe "Code gen: splat" do
       end
 
       def data
-        Global.x += 1
+        Global.x &+= 1
         {Global.x, Global.x, Global.x}
       end
 
       def test(x, y, z)
-        x + y + z
+        x &+ y &+ z
       end
 
       v = test(*data)
diff --git a/spec/compiler/codegen/ssa_spec.cr b/spec/compiler/codegen/ssa_spec.cr
index 829d9d893233..88f78c60e234 100644
--- a/spec/compiler/codegen/ssa_spec.cr
+++ b/spec/compiler/codegen/ssa_spec.cr
@@ -199,14 +199,14 @@ describe "Code gen: ssa" do
         i = 1
         while i <= 3
           yield i
-          i += 1
+          i &+= 1
         end
       end
 
       a = 0
       foo do |x|
         coconio = x if x == 1
-        a += coconio.to_i
+        a &+= coconio.to_i
       end
       a
       )).to_i.should eq(1)
diff --git a/spec/compiler/codegen/super_spec.cr b/spec/compiler/codegen/super_spec.cr
index d70d59a9f849..1b716ffe5ef8 100644
--- a/spec/compiler/codegen/super_spec.cr
+++ b/spec/compiler/codegen/super_spec.cr
@@ -6,7 +6,7 @@ describe "Codegen: super" do
   end
 
   it "codegens super without arguments but parent has arguments" do
-    run("class Foo; def foo(x); x + 1; end; end; class Bar < Foo; def foo(x); super; end; end; Bar.new.foo(1)").to_i.should eq(2)
+    run("class Foo; def foo(x); x &+ 1; end; end; class Bar < Foo; def foo(x); super; end; end; Bar.new.foo(1)").to_i.should eq(2)
   end
 
   it "codegens super without arguments and instance variable" do
@@ -222,13 +222,13 @@ describe "Codegen: super" do
         end
 
         def foo(z)
-          z + @x
+          z &+ @x
         end
       end
 
       class Bar < Foo
         def foo(z)
-          ->(x : Int32) { x + super }
+          ->(x : Int32) { x &+ super }
         end
       end
 
@@ -344,7 +344,7 @@ describe "Codegen: super" do
 
       class Bar(T) < Foo
         def initialize
-            Global.x += 1
+            Global.x &+= 1
             super
         end
       end
diff --git a/spec/compiler/codegen/tuple_spec.cr b/spec/compiler/codegen/tuple_spec.cr
index d2e49183d09b..bddd440ef23e 100644
--- a/spec/compiler/codegen/tuple_spec.cr
+++ b/spec/compiler/codegen/tuple_spec.cr
@@ -73,7 +73,7 @@ describe "Code gen: tuple" do
       end
 
       p = foo({1, 2})
-      p.value[0] + p.value[1]
+      p.value[0] &+ p.value[1]
       ").to_i.should eq(3)
   end
 
@@ -290,7 +290,7 @@ describe "Code gen: tuple" do
       if v.is_a?(Float64)
         10
       else
-        v[0].to_i + v[1].to_i
+        v[0].to_i &+ v[1].to_i
       end
       )).to_i.should eq(42)
   end
diff --git a/spec/compiler/codegen/uninitialized_spec.cr b/spec/compiler/codegen/uninitialized_spec.cr
index 8365854f09ed..137477099346 100644
--- a/spec/compiler/codegen/uninitialized_spec.cr
+++ b/spec/compiler/codegen/uninitialized_spec.cr
@@ -67,7 +67,7 @@ describe "Code gen: uninitialized" do
       end
 
       bar = Bar.new
-      bar.x + bar.y
+      bar.x &+ bar.y
       )).to_i.should eq(3)
   end
 
diff --git a/spec/compiler/codegen/union_type_spec.cr b/spec/compiler/codegen/union_type_spec.cr
index 196014c2b238..d09236429589 100644
--- a/spec/compiler/codegen/union_type_spec.cr
+++ b/spec/compiler/codegen/union_type_spec.cr
@@ -31,6 +31,18 @@ describe "Code gen: union type" do
 
   it "codegens union type for instance var" do
     run("
+      struct Float
+        def &+(other)
+          self + other
+        end
+      end
+
+      struct Int32
+        def &+(other : Float)
+          self + other
+        end
+      end
+
       class Foo
         @value : Int32 | Float32
 
@@ -43,7 +55,7 @@ describe "Code gen: union type" do
 
       f = Foo.new(1)
       f.value = 1.5_f32
-      (f.value + f.value).to_f
+      (f.value &+ f.value).to_f
     ").to_f64.should eq(3)
   end
 
diff --git a/spec/compiler/codegen/until_spec.cr b/spec/compiler/codegen/until_spec.cr
index 5cbc7891d444..d004402c038a 100644
--- a/spec/compiler/codegen/until_spec.cr
+++ b/spec/compiler/codegen/until_spec.cr
@@ -5,7 +5,7 @@ describe "Codegen: until" do
     run(%(
       a = 1
       until a == 10
-        a = a + 1
+        a = a &+ 1
       end
       a
     )).to_i.should eq(10)
diff --git a/spec/compiler/codegen/var_spec.cr b/spec/compiler/codegen/var_spec.cr
index 5a50636a0fc1..92455ceb6679 100644
--- a/spec/compiler/codegen/var_spec.cr
+++ b/spec/compiler/codegen/var_spec.cr
@@ -30,9 +30,9 @@ describe "Code gen: var" do
 
         def foo
           if 1 == 2
-            @angle += 1
+            @angle &+= 1
           else
-            @angle -= 1
+            @angle &-= 1
           end
         end
       end
diff --git a/spec/compiler/codegen/virtual_spec.cr b/spec/compiler/codegen/virtual_spec.cr
index 79af017fcd91..e4849c3cd3e5 100644
--- a/spec/compiler/codegen/virtual_spec.cr
+++ b/spec/compiler/codegen/virtual_spec.cr
@@ -110,7 +110,7 @@ describe "Code gen: virtual type" do
 
       class Bar < Foo
         def foo
-          @x + 1
+          @x &+ 1
         end
       end
 
diff --git a/spec/compiler/codegen/while_spec.cr b/spec/compiler/codegen/while_spec.cr
index ce05c540599d..f4467e62288a 100644
--- a/spec/compiler/codegen/while_spec.cr
+++ b/spec/compiler/codegen/while_spec.cr
@@ -10,15 +10,15 @@ describe "Codegen: while" do
   end
 
   it "codegens while with non-false condition" do
-    run("a = 1; while a < 10; a = a + 1; end; a").to_i.should eq(10)
+    run("a = 1; while a < 10; a = a &+ 1; end; a").to_i.should eq(10)
   end
 
   it "break without value" do
-    run("a = 0; while a < 10; a += 1; break; end; a").to_i.should eq(1)
+    run("a = 0; while a < 10; a &+= 1; break; end; a").to_i.should eq(1)
   end
 
   it "conditional break without value" do
-    run("a = 0; while a < 10; a += 1; break if a > 5; end; a").to_i.should eq(6)
+    run("a = 0; while a < 10; a &+= 1; break if a > 5; end; a").to_i.should eq(6)
   end
 
   it "codegens endless while" do
@@ -73,9 +73,9 @@ describe "Codegen: while" do
       x = 0
 
       while i < 10
-        i += 1
+        i &+= 1
         next if i.unsafe_mod(2) == 0
-        x += i
+        x &+= i
       end
       x
     ").to_i.should eq(25)
diff --git a/spec/compiler/codegen/yield_with_scope_spec.cr b/spec/compiler/codegen/yield_with_scope_spec.cr
index a0428dea88f9..dbef663cb82d 100644
--- a/spec/compiler/codegen/yield_with_scope_spec.cr
+++ b/spec/compiler/codegen/yield_with_scope_spec.cr
@@ -117,7 +117,7 @@ describe "Semantic: yield with scope" do
 
         def bar
           Foo.new.foo do
-            @x + 1
+            @x &+ 1
           end
         end
       end
@@ -137,7 +137,7 @@ describe "Semantic: yield with scope" do
       class Bar
         def bar
           Foo.new.foo do
-            baz + 1
+            baz &+ 1
           end
         end
 
@@ -162,7 +162,7 @@ describe "Semantic: yield with scope" do
         end
 
         def coco
-          @x + 1
+          @x &+ 1
         end
       end