[PHP 8.0] Add RemoveUnusedVariableInCatchRector

Author: TomasVotruba

composer.json

@@ -19,7 +19,7 @@
         "jetbrains/phpstorm-stubs": "^2019.3",
         "nette/robot-loader": "^3.2",
         "nette/utils": "^3.1",
-        "nikic/php-parser": "^4.4",
+        "nikic/php-parser": "^4.5",
         "ondram/ci-detector": "^3.4",
         "phpstan/phpdoc-parser": "^0.4.7",
         "phpstan/phpstan": "^0.12.25",
@@ -279,7 +279,5 @@
         "branch-alias": {
             "dev-master": "0.8-dev"
         }
-    },
-    "minimum-stability": "dev",
-    "prefer-stable": true
+    }
 }

config/set/php/php80.yaml

@@ -8,3 +8,4 @@ services:
     Rector\Php80\Rector\FuncCall\ClassOnObjectRector: null
     Rector\Php80\Rector\Ternary\GetDebugTypeRector: null
     Rector\Php80\Rector\FuncCall\TokenGetAllToObjectRector: null
+    Rector\Php80\Rector\Catch_\RemoveUnusedVariableInCatchRector: null

rules/php80/src/Rector/Catch_/RemoveUnusedVariableInCatchRector.php

@@ -0,0 +1,93 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Rector\Catch_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr\Variable;
+use PhpParser\Node\Stmt\Catch_;
+use Rector\Core\Rector\AbstractRector;
+use Rector\Core\RectorDefinition\CodeSample;
+use Rector\Core\RectorDefinition\RectorDefinition;
+
+/**
+ * @see https://wiki.php.net/rfc/non-capturing_catches
+ *
+ * @see \Rector\Php80\Tests\Rector\Catch_\RemoveUnusedVariableInCatchRector\RemoveUnusedVariableInCatchRectorTest
+ */
+final class RemoveUnusedVariableInCatchRector extends AbstractRector
+{
+    public function getDefinition(): RectorDefinition
+    {
+        return new RectorDefinition('Remove unused variable in catch()', [
+            new CodeSample(
+                <<<'PHP'
+final class SomeClass
+{
+    public function run()
+    {
+        try {
+        } catch (Throwable $notUsedThrowable) {
+        }
+    }
+}
+PHP
+,
+                <<<'PHP'
+final class SomeClass
+{
+    public function run()
+    {
+        try {
+        } catch (Throwable) {
+        }
+    }
+}
+PHP
+
+            ),
+        ]);
+    }
+
+    /**
+     * @return string[]
+     */
+    public function getNodeTypes(): array
+    {
+        return [Catch_::class];
+    }
+
+    /**
+     * @param Catch_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $caughtVar = $node->var;
+        if ($caughtVar === null) {
+            return null;
+        }
+
+        if ($this->isVariableUsed((array) $node->stmts, $caughtVar)) {
+            return null;
+        }
+
+        $node->var = null;
+
+        return $node;
+    }
+
+    /**
+     * @param Node[] $nodes
+     */
+    private function isVariableUsed(array $nodes, Variable $variable): bool
+    {
+        return (bool) $this->betterNodeFinder->findFirst($nodes, function (Node $node) use ($variable) {
+            if (! $node instanceof Variable) {
+                return false;
+            }
+
+            return $this->areNodesEqual($node, $variable);
+        });
+    }
+}

rules/php80/tests/Rector/Catch_/RemoveUnusedVariableInCatchRector/Fixture/fixture.php.inc

@@ -0,0 +1,31 @@
+<?php
+
+namespace Rector\Php80\Tests\Rector\Catch_\RemoveUnusedVariableInCatchRector\Fixture;
+
+final class SomeClass
+{
+    public function run()
+    {
+        try {
+        } catch (Throwable $notUsedThrowable) {
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Php80\Tests\Rector\Catch_\RemoveUnusedVariableInCatchRector\Fixture;
+
+final class SomeClass
+{
+    public function run()
+    {
+        try {
+        } catch (Throwable) {
+        }
+    }
+}
+
+?>

rules/php80/tests/Rector/Catch_/RemoveUnusedVariableInCatchRector/RemoveUnusedVariableInCatchRectorTest.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php80\Tests\Rector\Catch_\RemoveUnusedVariableInCatchRector;
+
+use Iterator;
+use Rector\Core\Testing\PHPUnit\AbstractRectorTestCase;
+use Rector\Php80\Rector\Catch_\RemoveUnusedVariableInCatchRector;
+
+final class RemoveUnusedVariableInCatchRectorTest 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 RemoveUnusedVariableInCatchRector::class;
+    }
+}