Skip already correct param type (#1688)

Co-authored-by: GitHub Action <action@github.com>

rules-tests/Php80/Rector/FunctionLike/UnionTypesRector/Fixture/skip_already_correct_type.php.inc

@@ -0,0 +1,17 @@
+<?php
+
+namespace Rector\Tests\Php80\Rector\FunctionLike\UnionTypesRector\Fixture;
+
+use Ds\Set;
+use Reflection;
+use stdClass;
+
+interface A
+{
+    /**
+     * @param Set<stdClass>|Set<Reflection> $list
+     */
+    public function execute(Set $list) : void;
+}
+
+?>

rules/Php80/Rector/FunctionLike/UnionTypesRector.php

@@ -5,9 +5,12 @@
 namespace Rector\Php80\Rector\FunctionLike;
 
 use PhpParser\Node;
+use PhpParser\Node\ComplexType;
 use PhpParser\Node\Expr\ArrowFunction;
 use PhpParser\Node\Expr\Closure;
+use PhpParser\Node\Identifier;
 use PhpParser\Node\Name;
+use PhpParser\Node\Name\FullyQualified;
 use PhpParser\Node\Param;
 use PhpParser\Node\Stmt\ClassMethod;
 use PhpParser\Node\Stmt\Function_;
@@ -155,11 +158,7 @@ private function refactorParamTypes(
                 TypeKind::PARAM()
             );
 
-            if (! $phpParserUnionType instanceof PhpParserUnionType) {
-                continue;
-            }
-
-            if ($param->type instanceof PhpParserUnionType) {
+            if ($this->shouldSkipParamTypeRefactor($param->type, $phpParserUnionType)) {
                 continue;
             }
 
@@ -242,4 +241,33 @@ private function filterOutDuplicatedArrayTypes(UnionType $unionType): UnionType
 
         return $this->typeFactory->createMixedPassedOrUnionType($singleArrayTypes);
     }
+
+    private function shouldSkipParamTypeRefactor(
+        Name|Identifier|ComplexType|null $type,
+        Name|ComplexType|Node|null $phpParserUnionType
+    ): bool {
+        if (! $phpParserUnionType instanceof PhpParserUnionType) {
+            return true;
+        }
+
+        if ($type instanceof PhpParserUnionType) {
+            return true;
+        }
+
+        if (count($phpParserUnionType->types) > 1) {
+            return false;
+        }
+
+        $firstType = $phpParserUnionType->types[0];
+
+        if (! $firstType instanceof FullyQualified) {
+            return false;
+        }
+
+        if (! $type instanceof FullyQualified) {
+            return false;
+        }
+
+        return $type->toString() === $firstType->toString();
+    }
 }