[CodeQuality] Add UnusedForeachValueToArrayKeysRector

config/set/code-quality/code-quality.yaml

@@ -55,3 +55,4 @@ services:
     Rector\CodeQuality\Rector\BinaryOp\InlineIfToExplicitIfRector: null
     Rector\CodeQuality\Rector\FuncCall\ArrayKeysAndInArrayToArrayKeyExistsRector: null
     Rector\CodeQuality\Rector\Assign\SplitListAssignToSeparateLineRector: null
+    Rector\CodeQuality\Rector\Foreach_\UnusedForeachValueToArrayKeysRector: null

docs/AllRectorsOverview.md

@@ -1,4 +1,4 @@
-# All 502 Rectors Overview
+# All 503 Rectors Overview
 
 - [Projects](#projects)
 - [General](#general)
@@ -1803,6 +1803,29 @@ Remove unnecessary ternary expressions.
 
 <br>
 
+### `UnusedForeachValueToArrayKeysRector`
+
+- class: [`Rector\CodeQuality\Rector\Foreach_\UnusedForeachValueToArrayKeysRector`](/../master/rules/code-quality/src/Rector/Foreach_/UnusedForeachValueToArrayKeysRector.php)
+- [test fixtures](/../master/rules/code-quality/tests/Rector/Foreach_/UnusedForeachValueToArrayKeysRector/Fixture)
+
+Change foreach with unused $value but only $key, to array_keys()
+
+```diff
+ class SomeClass
+ {
+     public function run()
+     {
+         $items = [];
+-        foreach ($values as $key => $value) {
++        foreach (array_keys($values) as $key) {
+             $items[$key] = null;
+         }
+     }
+ }
+```
+
+<br>
+
 ### `UseIdenticalOverEqualWithSameTypeRector`
 
 - class: [`Rector\CodeQuality\Rector\Equal\UseIdenticalOverEqualWithSameTypeRector`](/../master/rules/code-quality/src/Rector/Equal/UseIdenticalOverEqualWithSameTypeRector.php)

rules/code-quality/src/Rector/Foreach_/UnusedForeachValueToArrayKeysRector.php

@@ -0,0 +1,86 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\CodeQuality\Rector\Foreach_;
+
+use PhpParser\Node;
+use PhpParser\Node\Stmt\Foreach_;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Core\RectorDefinition\CodeSample;
+use Rector\Core\RectorDefinition\RectorDefinition;
+
+/**
+ * @see \Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector\UnusedForeachValueToArrayKeysRectorTest
+ */
+final class UnusedForeachValueToArrayKeysRector extends AbstractRector
+{
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Change foreach with unused $value but only $key, to array_keys()', [
+            new CodeSample(
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        $items = [];
+        foreach ($values as $key => $value) {
+            $items[$key] = null;
+        }
+    }
+}
+PHP
+,
+                <<<'PHP'
+class SomeClass
+{
+    public function run()
+    {
+        $items = [];
+        foreach (array_keys($values) as $key) {
+            $items[$key] = null;
+        }
+    }
+}
+PHP
+
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [Foreach_::class];
+    }
+
+    /**
+     * @param Foreach_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        if ($node->keyVar === null) {
+            return null;
+        }
+
+        $valueNode = $node->valueVar;
+        $isValueUsed = (bool) $this->betterNodeFinder->findFirst($node->stmts, function (Node $node) use ($valueNode) {
+            return $this->areNodesEqual($node, $valueNode);
+        });
+
+        if ($isValueUsed) {
+            return null;
+        }
+
+        // remove key value
+        $node->valueVar = $node->keyVar;
+        $node->keyVar = null;
+
+        $node->expr = $this->createFuncCall('array_keys', [$node->expr]);
+
+        return $node;
+    }
+}

rules/code-quality/tests/Rector/Foreach_/UnusedForeachValueToArrayKeysRector/Fixture/fixture.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector\Fixture;
+
+class SomeClass
+{
+    public function run()
+    {
+        $items = [];
+        foreach ($values as $key => $value) {
+            $items[$key] = null;
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector\Fixture;
+
+class SomeClass
+{
+    public function run()
+    {
+        $items = [];
+        foreach (array_keys($values) as $key) {
+            $items[$key] = null;
+        }
+    }
+}
+
+?>

rules/code-quality/tests/Rector/Foreach_/UnusedForeachValueToArrayKeysRector/Fixture/skip_no_key.php.inc

@@ -0,0 +1,14 @@
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector\Fixture;
+
+class SkipNoKey
+{
+    public function run()
+    {
+        $items = [];
+        foreach ($values as $value) {
+            $items[$value] = null;
+        }
+    }
+}

rules/code-quality/tests/Rector/Foreach_/UnusedForeachValueToArrayKeysRector/Fixture/skip_value_used.php.inc

@@ -0,0 +1,18 @@
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector\Fixture;
+
+class SkipValueUsed
+{
+    public function run()
+    {
+        $items = [];
+        foreach ($values as $key => $value) {
+            $items[$key] = null;
+
+            if (true) {
+                return $value;
+            }
+        }
+    }
+}

rules/code-quality/tests/Rector/Foreach_/UnusedForeachValueToArrayKeysRector/UnusedForeachValueToArrayKeysRectorTest.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\UnusedForeachValueToArrayKeysRector;
+
+use Iterator;
+use Rector\CodeQuality\Rector\Foreach_\UnusedForeachValueToArrayKeysRector;
+use Rector\Core\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class UnusedForeachValueToArrayKeysRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(string $file): void
+    {
+        $this->doTestFile($file);
+    }
+
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    protected function getRectorClass(): string
+    {
+        return UnusedForeachValueToArrayKeysRector::class;
+    }
+}