[Downgrade PHP 7.4] Fixed bug for CovariantReturnType downgrading (#4850)

rules/downgrade-php74/src/Rector/ClassMethod/DowngradeCovariantReturnTypeRector.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace Rector\DowngradePhp74\Rector\ClassMethod;
 
 use PhpParser\Node;
+use PhpParser\Node\Name;
 use PhpParser\Node\Name\FullyQualified;
 use PhpParser\Node\NullableType;
 use PhpParser\Node\Stmt\ClassMethod;
@@ -13,6 +14,7 @@ use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\ClassReflection;
 use Rector\BetterPhpDocParser\PhpDocInfo\PhpDocInfo;
 use Rector\Core\Rector\AbstractRector;
+use Rector\NodeTypeResolver\ClassExistenceStaticHelper;
 use Rector\NodeTypeResolver\Node\AttributeKey;
 use ReflectionMethod;
 use ReflectionNamedType;
@@ -88,8 +90,11 @@ CODE_SAMPLE
         }
 
         /** @var string */
-        $parentReflectionMethodClassname = $this->getDifferentReturnTypeClassnameFromAncestorClass($node);
-        $newType = new FullyQualified($parentReflectionMethodClassname);
+        $parentReflectionMethodName = $this->getDifferentReturnTypeNameFromAncestorClass($node);
+        // The return type name could either be a classname, without the leading "\",
+        // or one among the reserved identifiers ("static", "self", "iterable", etc)
+        // To find out which is the case, check if this name exists as a class
+        $newType = ClassExistenceStaticHelper::doesClassLikeExist($parentReflectionMethodName) ? new FullyQualified($parentReflectionMethodName) : new Name($parentReflectionMethodName);
 
         // Make it nullable?
         if ($node->returnType instanceof NullableType) {
@@ -106,10 +111,10 @@ CODE_SAMPLE
 
     private function shouldRefactor(ClassMethod $classMethod): bool
     {
-        return $this->getDifferentReturnTypeClassnameFromAncestorClass($classMethod) !== null;
+        return $this->getDifferentReturnTypeNameFromAncestorClass($classMethod) !== null;
     }
 
-    private function getDifferentReturnTypeClassnameFromAncestorClass(ClassMethod $classMethod): ?string
+    private function getDifferentReturnTypeNameFromAncestorClass(ClassMethod $classMethod): ?string
     {
         /** @var Scope|null $scope */
         $scope = $classMethod->getAttribute(AttributeKey::SCOPE);
@@ -127,7 +132,9 @@ CODE_SAMPLE
         if ($nodeReturnType === null || $nodeReturnType instanceof UnionType) {
             return null;
         }
-        $nodeReturnTypeName = $this->getName($nodeReturnType);
+        $nodeReturnTypeName = $this->getName(
+            $nodeReturnType instanceof NullableType ? $nodeReturnType->type : $nodeReturnType
+        );
 
         /** @var string $methodName */
         $methodName = $this->getName($classMethod->name);
@@ -153,7 +160,6 @@ CODE_SAMPLE
             if ($parentReflectionMethodReturnType === null || $parentReflectionMethodReturnType->getName() === $nodeReturnTypeName) {
                 continue;
             }
-
             // This is an ancestor class with a different return type
             return $parentReflectionMethodReturnType->getName();
         }

rules/downgrade-php74/tests/Rector/ClassMethod/DowngradeCovariantReturnTypeRector/Fixture/iterable.php.inc

@@ -0,0 +1,38 @@
+<?php
+
+namespace Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture;
+
+class InterableA
+{
+    public function covariantReturnTypes(): iterable
+    { /* … */ }
+}
+
+class InterableB extends InterableA
+{
+    public function covariantReturnTypes(): array
+    { /* … */ }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture;
+
+class InterableA
+{
+    public function covariantReturnTypes(): iterable
+    { /* … */ }
+}
+
+class InterableB extends InterableA
+{
+    /**
+     * @return mixed[]
+     */
+    public function covariantReturnTypes(): iterable
+    { /* … */ }
+}
+
+?>

rules/downgrade-php74/tests/Rector/ClassMethod/DowngradeCovariantReturnTypeRector/Fixture/nullable_scalar.php.inc

@@ -0,0 +1,20 @@
+<?php
+
+namespace Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture;
+
+class NullableScalarParentType {}
+class NullableScalarChildType extends NullableScalarParentType {}
+
+class NullableScalarA
+{
+    public function covariantReturnTypes(): ?string
+    { /* … */ }
+}
+
+class NullableScalarB extends NullableScalarA
+{
+    public function covariantReturnTypes(): ?string
+    { /* … */ }
+}
+
+?>

rules/downgrade-php74/tests/Rector/ClassMethod/DowngradeCovariantReturnTypeRector/Fixture/self.php.inc

@@ -0,0 +1,38 @@
+<?php
+
+namespace Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture;
+
+class SelfA
+{
+    public function covariantReturnTypes(): self
+    { /* … */ }
+}
+
+class SelfB extends SelfA
+{
+    public function covariantReturnTypes(): SelfB
+    { /* … */ }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture;
+
+class SelfA
+{
+    public function covariantReturnTypes(): self
+    { /* … */ }
+}
+
+class SelfB extends SelfA
+{
+    /**
+     * @return \Rector\DowngradePhp74\Tests\Rector\ClassMethod\DowngradeCovariantReturnTypeRector\Fixture\SelfB
+     */
+    public function covariantReturnTypes(): self
+    { /* … */ }
+}
+
+?>