From 80c05e3971bbf9289b13b3caaba0b9da10188618 Mon Sep 17 00:00:00 2001
From: Tomas Votruba <tomas.vot@gmail.com>
Date: Wed, 16 Sep 2026 16:52:42 +0200
Subject: [PATCH] [Php86] Add ConstructorReadonlyAssignToDefaultRector for
 readonly property defaults

---
 config/set/php-version-based.php              |   2 +
 config/set/php86.php                          |   3 +-
 ...uctorReadonlyAssignToDefaultRectorTest.php |  28 +++
 .../Fixture/class_const_default.php.inc       |  34 +++
 .../Fixture/fixture.php.inc                   |  30 +++
 .../Fixture/skip_conditional_assign.php.inc   |  17 ++
 .../Fixture/skip_new_object.php.inc           |  13 ++
 .../Fixture/skip_not_readonly.php.inc         |  13 ++
 .../Fixture/skip_variable_assign.php.inc      |  13 ++
 .../config/configured_rule.php                |  13 ++
 ...nstructorReadonlyAssignToDefaultRector.php | 200 ++++++++++++++++++
 src/ValueObject/PhpVersionFeature.php         |   5 +
 12 files changed, 370 insertions(+), 1 deletion(-)
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/ConstructorReadonlyAssignToDefaultRectorTest.php
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/class_const_default.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/fixture.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_conditional_assign.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_new_object.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_not_readonly.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_variable_assign.php.inc
 create mode 100644 rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/config/configured_rule.php
 create mode 100644 rules/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector.php

diff --git a/config/set/php-version-based.php b/config/set/php-version-based.php
index 42289f31469..89a3c2c4c2f 100644
--- a/config/set/php-version-based.php
+++ b/config/set/php-version-based.php
@@ -139,6 +139,7 @@
 use Rector\Php85\Rector\Property\AddOverrideAttributeToOverriddenPropertiesRector;
 use Rector\Php85\Rector\ShellExec\ShellExecFunctionCallOverBackticksRector;
 use Rector\Php85\Rector\Switch_\ColonAfterSwitchCaseRector;
+use Rector\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector;
 use Rector\Php86\Rector\FuncCall\MinMaxToClampRector;
 use Rector\Removing\Rector\FuncCall\RemoveFuncCallArgRector;
 use Rector\Removing\Rector\FuncCall\RemoveFuncCallRector;
@@ -325,6 +326,7 @@
 
         // PHP 8.6
         MinMaxToClampRector::class,
+        ConstructorReadonlyAssignToDefaultRector::class,
     ]);
 
     // configured rules, each bound to the PHP version its configuration targets
diff --git a/config/set/php86.php b/config/set/php86.php
index 9eb067e51ea..dd823ce93b7 100644
--- a/config/set/php86.php
+++ b/config/set/php86.php
@@ -3,8 +3,9 @@
 declare(strict_types=1);
 
 use Rector\Config\RectorConfig;
+use Rector\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector;
 use Rector\Php86\Rector\FuncCall\MinMaxToClampRector;
 
 return static function (RectorConfig $rectorConfig): void {
-    $rectorConfig->rules([MinMaxToClampRector::class]);
+    $rectorConfig->rules([MinMaxToClampRector::class, ConstructorReadonlyAssignToDefaultRector::class]);
 };
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/ConstructorReadonlyAssignToDefaultRectorTest.php b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/ConstructorReadonlyAssignToDefaultRectorTest.php
new file mode 100644
index 00000000000..f2e442a1e36
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/ConstructorReadonlyAssignToDefaultRectorTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class ConstructorReadonlyAssignToDefaultRectorTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/class_const_default.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/class_const_default.php.inc
new file mode 100644
index 00000000000..ca1141a8b5c
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/class_const_default.php.inc
@@ -0,0 +1,34 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class ClassConstDefault
+{
+    private const DEFAULT_NAME = 'value';
+
+    public readonly string $name;
+
+    public function __construct()
+    {
+        $this->name = self::DEFAULT_NAME;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class ClassConstDefault
+{
+    private const DEFAULT_NAME = 'value';
+
+    public readonly string $name = self::DEFAULT_NAME;
+
+    public function __construct()
+    {
+    }
+}
+
+?>
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/fixture.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/fixture.php.inc
new file mode 100644
index 00000000000..8732e0c48bb
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/fixture.php.inc
@@ -0,0 +1,30 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class Fixture
+{
+    public readonly int $number;
+
+    public function __construct()
+    {
+        $this->number = 100;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class Fixture
+{
+    public readonly int $number = 100;
+
+    public function __construct()
+    {
+    }
+}
+
+?>
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_conditional_assign.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_conditional_assign.php.inc
new file mode 100644
index 00000000000..fae82114ef4
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_conditional_assign.php.inc
@@ -0,0 +1,17 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class SkipConditionalAssign
+{
+    public readonly int $number;
+
+    public function __construct(bool $flag)
+    {
+        if ($flag) {
+            $this->number = 100;
+        } else {
+            $this->number = 200;
+        }
+    }
+}
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_new_object.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_new_object.php.inc
new file mode 100644
index 00000000000..a9db071834a
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_new_object.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class SkipNewObject
+{
+    public readonly \stdClass $value;
+
+    public function __construct()
+    {
+        $this->value = new \stdClass();
+    }
+}
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_not_readonly.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_not_readonly.php.inc
new file mode 100644
index 00000000000..de5c186c6fe
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_not_readonly.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class SkipNotReadonly
+{
+    public int $number;
+
+    public function __construct()
+    {
+        $this->number = 100;
+    }
+}
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_variable_assign.php.inc b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_variable_assign.php.inc
new file mode 100644
index 00000000000..63ec63fdc72
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/Fixture/skip_variable_assign.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\Fixture;
+
+final class SkipVariableAssign
+{
+    public readonly int $number;
+
+    public function __construct(int $number)
+    {
+        $this->number = $number;
+    }
+}
diff --git a/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/config/configured_rule.php b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/config/configured_rule.php
new file mode 100644
index 00000000000..efa2aa199aa
--- /dev/null
+++ b/rules-tests/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector/config/configured_rule.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector;
+use Rector\ValueObject\PhpVersion;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rule(ConstructorReadonlyAssignToDefaultRector::class);
+
+    $rectorConfig->phpVersion(PhpVersion::PHP_86);
+};
diff --git a/rules/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector.php b/rules/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector.php
new file mode 100644
index 00000000000..e49c76191c8
--- /dev/null
+++ b/rules/Php86/Rector/Class_/ConstructorReadonlyAssignToDefaultRector.php
@@ -0,0 +1,200 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Php86\Rector\Class_;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\ClassConstFetch;
+use PhpParser\Node\Expr\ConstFetch;
+use PhpParser\Node\Expr\PropertyFetch;
+use PhpParser\Node\Expr\UnaryMinus;
+use PhpParser\Node\Expr\UnaryPlus;
+use PhpParser\Node\Scalar;
+use PhpParser\Node\Stmt\Class_;
+use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Expression;
+use PhpParser\Node\Stmt\Property;
+use Rector\Rector\AbstractRector;
+use Rector\ValueObject\MethodName;
+use Rector\ValueObject\PhpVersionFeature;
+use Rector\VersionBonding\Contract\MinPhpVersionInterface;
+use Symplify\RuleDocGenerator\ValueObject\CodeSample\CodeSample;
+use Symplify\RuleDocGenerator\ValueObject\RuleDefinition;
+
+/**
+ * @see https://wiki.php.net/rfc/readonly_property_defaults
+ * @see \Rector\Tests\Php86\Rector\Class_\ConstructorReadonlyAssignToDefaultRector\ConstructorReadonlyAssignToDefaultRectorTest
+ */
+final class ConstructorReadonlyAssignToDefaultRector extends AbstractRector implements MinPhpVersionInterface
+{
+    public function getRuleDefinition(): RuleDefinition
+    {
+        return new RuleDefinition(
+            'Move a constant constructor assignment of a readonly property to a property default value',
+            [
+                new CodeSample(
+                    <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public readonly int $number;
+
+    public function __construct()
+    {
+        $this->number = 100;
+    }
+}
+CODE_SAMPLE
+                    ,
+                    <<<'CODE_SAMPLE'
+final class SomeClass
+{
+    public readonly int $number = 100;
+
+    public function __construct()
+    {
+    }
+}
+CODE_SAMPLE
+                ),
+            ]
+        );
+    }
+
+    public function getNodeTypes(): array
+    {
+        return [Class_::class];
+    }
+
+    /**
+     * @param Class_ $node
+     */
+    public function refactor(Node $node): ?Node
+    {
+        $constructClassMethod = $node->getMethod(MethodName::CONSTRUCT);
+        if (! $constructClassMethod instanceof ClassMethod) {
+            return null;
+        }
+
+        if ($constructClassMethod->stmts === null) {
+            return null;
+        }
+
+        $keysToRemove = [];
+
+        foreach ($node->getProperties() as $property) {
+            if (! $this->isDefaultableReadonlyProperty($property)) {
+                continue;
+            }
+
+            $propertyName = $this->getName($property->props[0]);
+
+            $assignKey = $this->matchConstantAssignKey($constructClassMethod->stmts, $propertyName);
+            if ($assignKey === null) {
+                continue;
+            }
+
+            $expression = $constructClassMethod->stmts[$assignKey];
+            if (! $expression instanceof Expression || ! $expression->expr instanceof Assign) {
+                continue;
+            }
+
+            $property->props[0]->default = $expression->expr->expr;
+            $keysToRemove[] = $assignKey;
+        }
+
+        if ($keysToRemove === []) {
+            return null;
+        }
+
+        foreach ($keysToRemove as $keyToRemove) {
+            unset($constructClassMethod->stmts[$keyToRemove]);
+        }
+
+        $constructClassMethod->stmts = array_values($constructClassMethod->stmts);
+
+        return $node;
+    }
+
+    public function provideMinPhpVersion(): int
+    {
+        return PhpVersionFeature::READONLY_PROPERTY_DEFAULT_VALUE;
+    }
+
+    private function isDefaultableReadonlyProperty(Property $property): bool
+    {
+        if (! $property->isReadonly()) {
+            return false;
+        }
+
+        if ($property->isStatic()) {
+            return false;
+        }
+
+        if ($property->hooks !== []) {
+            return false;
+        }
+
+        if (count($property->props) !== 1) {
+            return false;
+        }
+
+        return ! $property->props[0]->default instanceof Expr;
+    }
+
+    /**
+     * @param Node\Stmt[] $stmts
+     */
+    private function matchConstantAssignKey(array $stmts, string $propertyName): ?int
+    {
+        foreach ($stmts as $key => $stmt) {
+            if (! $stmt instanceof Expression) {
+                continue;
+            }
+
+            if (! $stmt->expr instanceof Assign) {
+                continue;
+            }
+
+            $assign = $stmt->expr;
+            if (! $assign->var instanceof PropertyFetch) {
+                continue;
+            }
+
+            if (! $this->isName($assign->var->var, 'this')) {
+                continue;
+            }
+
+            if (! $this->isName($assign->var->name, $propertyName)) {
+                continue;
+            }
+
+            if (! $this->isConstantValue($assign->expr)) {
+                return null;
+            }
+
+            return $key;
+        }
+
+        return null;
+    }
+
+    private function isConstantValue(Expr $expr): bool
+    {
+        if ($expr instanceof Scalar) {
+            return true;
+        }
+
+        if ($expr instanceof ConstFetch || $expr instanceof ClassConstFetch) {
+            return true;
+        }
+
+        if ($expr instanceof UnaryMinus || $expr instanceof UnaryPlus) {
+            return $this->isConstantValue($expr->expr);
+        }
+
+        return false;
+    }
+}
diff --git a/src/ValueObject/PhpVersionFeature.php b/src/ValueObject/PhpVersionFeature.php
index bcc06cd7c37..c4108883ad6 100644
--- a/src/ValueObject/PhpVersionFeature.php
+++ b/src/ValueObject/PhpVersionFeature.php
@@ -506,6 +506,11 @@ final class PhpVersionFeature
      */
     public const int CLAMP = PhpVersion::PHP_86;
 
+    /**
+     * @see https://wiki.php.net/rfc/readonly_property_defaults
+     */
+    public const int READONLY_PROPERTY_DEFAULT_VALUE = PhpVersion::PHP_86;
+
     /**
      * @see https://php.watch/versions/8.0/named-parameters
      */