fix union type on ReturnTypeDeclarationRector

rules/type-declaration/src/TypeAlreadyAddedChecker/ReturnTypeAlreadyAddedChecker.php

@@ -6,12 +6,17 @@ namespace Rector\TypeDeclaration\TypeAlreadyAddedChecker;
 
 use Iterator;
 use PhpParser\Node;
+use PhpParser\Node\Identifier;
+use PhpParser\Node\Name;
+use PhpParser\Node\NullableType;
 use PhpParser\Node\Stmt\ClassMethod;
 use PhpParser\Node\Stmt\Function_;
+use PhpParser\Node\UnionType as PhpParserUnionType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\Generic\GenericObjectType;
 use PHPStan\Type\IntersectionType;
 use PHPStan\Type\IterableType;
+use PHPStan\Type\NullType;
 use PHPStan\Type\ObjectType;
 use PHPStan\Type\Type;
 use PHPStan\Type\UnionType;
@@ -57,17 +62,24 @@ final class ReturnTypeAlreadyAddedChecker
      */
     public function isReturnTypeAlreadyAdded(Node $node, Type $returnType): bool
     {
-        $returnNode = $this->staticTypeMapper->mapPHPStanTypeToPhpParserNode($returnType);
-        if ($node->returnType === null) {
+        $nodeReturnType = $node->returnType;
+
+        /** @param Identifier|Name|NullableType|PhpParserUnionType|null $returnTypeNode */
+        if ($nodeReturnType === null) {
             return false;
         }
 
-        if ($this->betterStandardPrinter->areNodesEqual($node->returnType, $returnNode)) {
+        $returnNode = $this->staticTypeMapper->mapPHPStanTypeToPhpParserNode($returnType);
+        if ($this->betterStandardPrinter->areNodesEqual($nodeReturnType, $returnNode)) {
             return true;
         }
 
         // is array <=> iterable <=> Iterator co-type? → skip
-        if ($this->isArrayIterableIteratorCoType($node, $returnType)) {
+        if ($this->isArrayIterableIteratorCoType($nodeReturnType, $returnType)) {
+            return true;
+        }
+
+        if ($this->isUnionCoType($nodeReturnType, $returnType)) {
             return true;
         }
 
@@ -87,9 +99,12 @@ final class ReturnTypeAlreadyAddedChecker
         return false;
     }
 
-    private function isArrayIterableIteratorCoType(Node $node, Type $returnType): bool
+    /**
+     * @param Identifier|Name|NullableType|PhpParserUnionType $returnTypeNode
+     */
+    private function isArrayIterableIteratorCoType(Node $returnTypeNode, Type $returnType): bool
     {
-        if (! $this->nodeNameResolver->isNames($node->returnType, self::FOREACHABLE_TYPES)) {
+        if (! $this->nodeNameResolver->isNames($returnTypeNode, self::FOREACHABLE_TYPES)) {
             return false;
         }
 
@@ -127,4 +142,23 @@ final class ReturnTypeAlreadyAddedChecker
 
         return $type instanceof ObjectType && $type->getClassName() === Iterator::class;
     }
+
+    /**
+     * @param Identifier|Name|NullableType|PhpParserUnionType $returnTypeNode
+     */
+    private function isUnionCoType(Node $returnTypeNode, Type $type): bool
+    {
+        if (! $type instanceof UnionType) {
+            return false;
+        }
+
+        // skip nullable type
+        $nullType = new NullType();
+        if ($type->isSuperTypeOf($nullType)->yes()) {
+            return false;
+        }
+
+        $classMethodReturnType = $this->staticTypeMapper->mapPhpParserNodePHPStanType($returnTypeNode);
+        return $type->isSuperTypeOf($classMethodReturnType)->yes();
+    }
 }

rules/type-declaration/tests/Rector/FunctionLike/ReturnTypeDeclarationRector/Fixture/skip_parent_and_child.php.inc

@@ -0,0 +1,23 @@
+<?php
+
+namespace Rector\TypeDeclaration\Tests\Rector\ClassMethod\ReturnTypeDeclarationRector\Fixture;
+
+class Response
+{
+}
+
+final class RedirectResponse extends Response
+{
+}
+
+final class SkipParentAndChild
+{
+    public function run(bool $response): Response
+    {
+        if ($response) {
+            return new RedirectResponse;
+        }
+
+        return new Response;
+    }
+}