[DeadCode] Add RemoveJustVariableAssignRector

config/set/early-return.php

@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
+use Rector\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector;
 use Rector\EarlyReturn\Rector\Foreach_\ChangeNestedForeachIfsToEarlyContinueRector;
 use Rector\EarlyReturn\Rector\Foreach_\ReturnAfterToEarlyOnBreakRector;
 use Rector\EarlyReturn\Rector\If_\ChangeAndIfToEarlyReturnRector;
@@ -17,16 +18,19 @@
 use Rector\EarlyReturn\Rector\StmtsAwareInterface\ReturnEarlyIfVariableRector;
 
 return static function (RectorConfig $rectorConfig): void {
-    $rectorConfig->rule(ChangeNestedForeachIfsToEarlyContinueRector::class);
-    $rectorConfig->rule(ChangeAndIfToEarlyReturnRector::class);
-    $rectorConfig->rule(ChangeIfElseValueAssignToEarlyReturnRector::class);
-    $rectorConfig->rule(ChangeNestedIfsToEarlyReturnRector::class);
-    $rectorConfig->rule(RemoveAlwaysElseRector::class);
-    $rectorConfig->rule(ReturnBinaryAndToEarlyReturnRector::class);
-    $rectorConfig->rule(ChangeOrIfReturnToEarlyReturnRector::class);
-    $rectorConfig->rule(ChangeOrIfContinueToMultiContinueRector::class);
-    $rectorConfig->rule(ReturnAfterToEarlyOnBreakRector::class);
-    $rectorConfig->rule(PreparedValueToEarlyReturnRector::class);
-    $rectorConfig->rule(ReturnBinaryOrToEarlyReturnRector::class);
-    $rectorConfig->rule(ReturnEarlyIfVariableRector::class);
+    $rectorConfig->rules([
+        ChangeNestedForeachIfsToEarlyContinueRector::class,
+        ChangeAndIfToEarlyReturnRector::class,
+        ChangeIfElseValueAssignToEarlyReturnRector::class,
+        ChangeNestedIfsToEarlyReturnRector::class,
+        RemoveAlwaysElseRector::class,
+        ReturnBinaryAndToEarlyReturnRector::class,
+        ChangeOrIfReturnToEarlyReturnRector::class,
+        ChangeOrIfContinueToMultiContinueRector::class,
+        ReturnAfterToEarlyOnBreakRector::class,
+        PreparedValueToEarlyReturnRector::class,
+        ReturnBinaryOrToEarlyReturnRector::class,
+        ReturnEarlyIfVariableRector::class,
+        RemoveJustVariableAssignRector::class,
+    ]);
 };

rules-tests/DeadCode/Rector/StmtsAwareInterface/RemoveJustVariableAssignRector/Fixture/skip_referenced_variable.php.inc

@@ -0,0 +1,15 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector\Fixture;
+
+final class SkipReferencedVariable
+{
+    private $temporaryValue;
+
+    public function run(&$result)
+    {
+        $result = 100;
+
+        $this->temporaryValue = $result;
+    }
+}

rules-tests/DeadCode/Rector/StmtsAwareInterface/RemoveJustVariableAssignRector/Fixture/some_class.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector\Fixture;
+
+final class SomeClass
+{
+    private int $temporaryValue;
+
+    public function run()
+    {
+        $result = 100;
+
+        $this->temporaryValue = $result;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector\Fixture;
+
+final class SomeClass
+{
+    private int $temporaryValue;
+
+    public function run()
+    {
+        $this->temporaryValue = 100;
+    }
+}
+
+?>

rules-tests/DeadCode/Rector/StmtsAwareInterface/RemoveJustVariableAssignRector/RemoveJustVariableAssignRectorTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector;
+
+use Iterator;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+use Symplify\SmartFileSystem\SmartFileInfo;
+
+final class RemoveJustVariableAssignRectorTest extends AbstractRectorTestCase
+{
+    /**
+     * @dataProvider provideData()
+     */
+    public function test(SmartFileInfo $fileInfo): void
+    {
+        $this->doTestFileInfo($fileInfo);
+    }
+
+    /**
+     * @return Iterator<SmartFileInfo>
+     */
+    public function provideData(): Iterator
+    {
+        return $this->yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}

rules-tests/DeadCode/Rector/StmtsAwareInterface/RemoveJustVariableAssignRector/config/configured_rule.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(RemoveJustVariableAssignRector::class);
+};

rules/DeadCode/Rector/StmtsAwareInterface/RemoveJustPropertyFetchRector.php

@@ -177,7 +177,7 @@ function (Node $node) use ($variableUsages, $propertyFetch): ?PropertyFetch {
                 $parentNode = $node->getAttribute(AttributeKey::PARENT_NODE);
                 if ($parentNode instanceof ClosureUse) {
                     // remove closure use which will be replaced by a property fetch
-                    $this->nodesToRemoveCollector->addNodeToRemove($parentNode);
+                    $this->removeNode($parentNode);
 
                     return null;
                 }

rules/DeadCode/Rector/StmtsAwareInterface/RemoveJustVariableAssignRector.php

@@ -0,0 +1,145 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\DeadCode\Rector\StmtsAwareInterface;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Stmt\Expression;
+use Rector\Core\Contract\PhpParser\Node\StmtsAwareInterface;
+use Rector\Core\NodeAnalyzer\VariableAnalyzer;
+use Rector\Core\Rector\AbstractRector;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see \Rector\Tests\DeadCode\Rector\StmtsAwareInterface\RemoveJustVariableAssignRector\RemoveJustVariableAssignRectorTest
+ */
+final class RemoveJustVariableAssignRector extends AbstractRector
+{
+    public function __construct(
+        private VariableAnalyzer $variableAnalyzer
+    ) {
+    }
+
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition('Remove variable just to assign value or return value', [
+            new CodeSample(
+                <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public function run()
+    {
+        $result = 100;
+
+        $this->temporaryValue = $result;
+    }
+}
+CODE_SAMPLE
+
+                ,
+                <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public function run()
+    {
+        $this->temporaryValue = 100;
+    }
+}
+CODE_SAMPLE
+            ),
+        ]);
+    }
+
+    /**
+     * @return array<class-string<Node>>
+     */
+    public function getNodeTypes(): array
+    {
+        return [StmtsAwareInterface::class];
+    }
+
+    /**
+     * @param StmtsAwareInterface $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $stmts = (array) $node->stmts;
+        if ($stmts === []) {
+            return null;
+        }
+
+        $originalStmts = $stmts;
+
+        foreach ($stmts as $key => $stmt) {
+            $nextStmt = $stmts[$key + 1] ?? null;
+
+            if (! $stmt instanceof Expression) {
+                continue;
+            }
+
+            if (! $stmt->expr instanceof Assign) {
+                continue;
+            }
+
+            $currentAssign = $stmt->expr;
+
+            if (! $nextStmt instanceof Expression) {
+                continue;
+            }
+
+            if (! $nextStmt->expr instanceof Assign) {
+                continue;
+            }
+
+            $nextAssign = $nextStmt->expr;
+
+            if (! $this->areTwoVariablesCrossAssign($currentAssign, $nextAssign)) {
+                continue;
+            }
+
+            // ...
+            $currentAssign->var = $nextAssign->var;
+            unset($stmts[$key + 1]);
+        }
+
+        if ($originalStmts === $stmts) {
+            return null;
+        }
+
+        $node->stmts = $stmts;
+
+        return $node;
+    }
+
+    /**
+     * This detects if two variables are cross assigned:
+     *
+     * $<some> = 1000;
+     * $this->value = $<some>;
+     */
+    private function areTwoVariablesCrossAssign(Assign $currentAssign, Assign $nextAssign): bool
+    {
+        // is just re-assign to variable
+        if (! $currentAssign->var instanceof Variable) {
+            return false;
+        }
+
+        if (! $nextAssign->expr instanceof Variable) {
+            return false;
+        }
+
+        if (! $this->nodeComparator->areNodesEqual($currentAssign->var, $nextAssign->expr)) {
+            return false;
+        }
+
+        if ($this->variableAnalyzer->isUsedByReference($currentAssign->var)) {
+            return false;
+        }
+
+        return ! $this->variableAnalyzer->isUsedByReference($nextAssign->expr);
+    }
+}

src/Rector/AbstractRector.php

@@ -91,8 +91,6 @@ abstract class AbstractRector extends NodeVisitorAbstract implements PhpRectorIn
 
     protected NodeComparator $nodeComparator;
 
-    protected NodesToRemoveCollector $nodesToRemoveCollector;
-
     protected File $file;
 
     protected NodesToAddCollector $nodesToAddCollector;
@@ -103,6 +101,8 @@ abstract class AbstractRector extends NodeVisitorAbstract implements PhpRectorIn
 
     protected ScopeFactory $scopeFactory;
 
+    private NodesToRemoveCollector $nodesToRemoveCollector;
+
     private SimpleCallableNodeTraverser $simpleCallableNodeTraverser;
 
     private ExclusionManager $exclusionManager;