[DeadCode] Skip negative zero on RemoveDeadZeroAndOneOperationRector

rules-tests/DeadCode/Rector/Plus/RemoveDeadZeroAndOneOperationRector/Fixture/skip_assign_plus_negative_zero.php.inc

@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Plus\RemoveDeadZeroAndOneOperationRector\Fixture;
+
+final class SkipAssignPlusNegativeZero
+{
+    protected function run()
+    {
+        $value = round(-0.001, 2);
+        var_dump((string) $value);
+
+        $value += 0;
+        var_dump((string) $value);
+    }
+}

rules-tests/DeadCode/Rector/Plus/RemoveDeadZeroAndOneOperationRector/Fixture/skip_negative_zero.php.inc

@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Plus\RemoveDeadZeroAndOneOperationRector\Fixture;
+
+final class SkipNegativeZero
+{
+    protected function run()
+    {
+        $value = round(-0.001, 2);
+        var_dump((string) $value);
+
+        $value = $value + 0;
+        var_dump((string) $value);
+    }
+}

rules-tests/DeadCode/Rector/Plus/RemoveDeadZeroAndOneOperationRector/Fixture/skip_zero_minus_positive_zero.php.inc

@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Plus\RemoveDeadZeroAndOneOperationRector\Fixture;
+
+final class SkipZeroMinusPositiveZero
+{
+    protected function run()
+    {
+        $value = 0.0;
+        var_dump((string) $value);
+
+        $value = 0 - $value;
+        var_dump((string) $value);
+    }
+}

rules-tests/DeadCode/Rector/Plus/RemoveDeadZeroAndOneOperationRector/Fixture/skip_zero_plus_negative_zero.php.inc

@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Plus\RemoveDeadZeroAndOneOperationRector\Fixture;
+
+final class SkipZeroPlusNegativeZero
+{
+    protected function run()
+    {
+        $value = round(-0.001, 2);
+        var_dump((string) $value);
+
+        $value = 0 + $value;
+        var_dump((string) $value);
+    }
+}

rules/DeadCode/Rector/Plus/RemoveDeadZeroAndOneOperationRector.php

@@ -100,6 +100,13 @@ private function processAssignOp(AssignOp $assignOp): ?Expr
                 return null;
             }
 
+            // on float, += 0 normalizes negative zero (-0.0) to 0.0, so it is not dead
+            if ($assignOp instanceof AssignPlus && ! $this->nodeTypeResolver->getNativeType($assignOp->var)
+                ->isInteger()
+                ->yes()) {
+                return null;
+            }
+
             if ($this->nodeTypeResolver->isNumberType($assignOp->var)) {
                 return $assignOp->var;
             }
@@ -152,7 +159,15 @@ private function processBinaryPlusAndMinus(Plus|Minus $binaryOp): ?Expr
             return null;
         }
 
-        if ($this->isLiteralZero($binaryOp->left) && $this->nodeTypeResolver->isNumberType($binaryOp->right)) {
+        if ($this->isLiteralZero($binaryOp->left)) {
+            // on float, 0 + $x normalizes negative zero (-0.0) to 0.0 and 0 - $x flips its sign,
+            // so the operation is not dead
+            if (! $this->nodeTypeResolver->getNativeType($binaryOp->right)
+                ->isInteger()
+                ->yes()) {
+                return null;
+            }
+
             if ($binaryOp instanceof Minus) {
                 return new UnaryMinus($binaryOp->right);
             }
@@ -164,6 +179,13 @@ private function processBinaryPlusAndMinus(Plus|Minus $binaryOp): ?Expr
             return null;
         }
 
+        // on float, $x + 0 normalizes negative zero (-0.0) to 0.0, so it is not dead
+        if ($binaryOp instanceof Plus && ! $this->nodeTypeResolver->getNativeType($binaryOp->left)
+            ->isInteger()
+            ->yes()) {
+            return null;
+        }
+
         return $binaryOp->left;
     }