Ignore 1 in Div assignment operator (DivEqual). (#1886)

src/Mutator/Arithmetic/DivEqual.php

@@ -78,6 +78,27 @@ public function mutate(Node $node): iterable
 
  public function canMutate(Node $node): bool
  {
- return $node instanceof Node\Expr\AssignOp\Div;
+ if (!$node instanceof Node\Expr\AssignOp\Div) {
+ return false;
+ }
+
+ if ($this->isNumericOne($node->expr)) {
+ return false;
+ }
+
+ if ($node->expr instanceof Node\Expr\UnaryMinus && $this->isNumericOne($node->expr->expr)) {
+ return false;
+ }
+
+ return true;
+ }
+
+ private function isNumericOne(Node $node): bool
+ {
+ if ($node instanceof Node\Scalar\LNumber && $node->value === 1) {
+ return true;
+ }
+
+ return $node instanceof Node\Scalar\DNumber && $node->value === 1.0;
  }
 }

tests/phpunit/Mutator/Arithmetic/DivEqualTest.php

@@ -73,6 +73,46 @@ public function mutationsProvider(): iterable
 <?php
 
 $a = 10 / 2;
+PHP
+ ,
+ ];
+
+ yield 'It does not mutate division by 1 to avoid an equivalent mutation' => [
+ <<<'PHP'
+<?php
+
+$a = 1;
+$a /= 1;
+PHP
+ ,
+ ];
+
+ yield 'It does not mutate division by -1 to avoid an equivalent mutation' => [
+ <<<'PHP'
+<?php
+
+$a = 1;
+$a /= -1;
+PHP
+ ,
+ ];
+
+ yield 'It does not mutate division by 1.0 to avoid an equivalent mutation' => [
+ <<<'PHP'
+<?php
+
+$a = 1;
+$a /= 1.0;
+PHP
+ ,
+ ];
+
+ yield 'It does not mutate division by -1.0 to avoid an equivalent mutation' => [
+ <<<'PHP'
+<?php
+
+$a = 1;
+$a /= -1.0;
 PHP
  ,
  ];