chore: skip methods with native mixed return types

Author: calebdw

rules-tests/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector/Fixture/arrow_function.php.inc

@@ -2,24 +2,24 @@
 
 namespace Rector\Tests\DeadCode\Rector\FunctionLike\NarrowTooWideReturnTypeRector\Fixture;
 
-$simple = fn(int $x): string|int|bool => $x > 5 ? 'high' : 10;
+$simple = fn($x): string|int|bool => $x > 5 ? 'high' : 10;
 
-$ternary = fn(?int $value): string|int|float|null =>
+$ternary = fn($value): string|int|float|null =>
     $value === null ? null : ($value > 0 ? 'positive' : -1);
 
-$cast = fn(mixed $input): int|string|array => (int) $input;
+$cast = fn($input): int|string|array => (int) $input;
 
 ?>
 -----
 <?php
 
 namespace Rector\Tests\DeadCode\Rector\FunctionLike\NarrowTooWideReturnTypeRector\Fixture;
 
-$simple = fn(int $x): string|int => $x > 5 ? 'high' : 10;
+$simple = fn($x): string|int => $x > 5 ? 'high' : 10;
 
-$ternary = fn(?int $value): string|int|null =>
+$ternary = fn($value): string|int|null =>
     $value === null ? null : ($value > 0 ? 'positive' : -1);
 
-$cast = fn(mixed $input): int => (int) $input;
+$cast = fn($input): int => (int) $input;
 
 ?>

…on_likes_without_parameter_types.php.inc …ixture/skip_native_mixed_returns.php.incrules-tests/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector/Fixture/skip_function_likes_without_parameter_types.php.inc renamed to rules-tests/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector/Fixture/skip_native_mixed_returns.php.inc rules-tests/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector/Fixture/skip_function_likes_without_parameter_types.php.inc renamed to rules-tests/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector/Fixture/skip_native_mixed_returns.php.inc

@@ -12,6 +12,18 @@ final class SkipFunctionLikesWithoutParameterTypes
     {
         return $class;
     }
+
+    /**
+     * @return class-string<\stdClass>|int
+     */
+    public function skipMixedByDoc(): string|int
+    {
+        /**
+         * @var class-string<\stdClass> $class
+         */
+        $class = get();
+        return $class;
+    }
 }
 
 ?>

rules/DeadCode/Rector/FunctionLike/NarrowTooWideReturnTypeRector.php

@@ -4,6 +4,7 @@
 
 namespace Rector\DeadCode\Rector\FunctionLike;
 
+use PHPStan\Type\MixedType;
 use PhpParser\Node;
 use PhpParser\Node\Expr\ArrowFunction;
 use PhpParser\Node\Expr\Closure;
@@ -134,6 +135,11 @@ public function refactor(Node $node): ?Node
         }
 
         $actualReturnTypes = $this->collectActualReturnTypes($node, $returnStatements, $isAlwaysTerminating);
+
+        if ($actualReturnTypes === null) {
+            return null;
+        }
+
         $newReturnType = $this->narrowReturnType($returnType, $actualReturnTypes);
 
         if ($newReturnType === null) {
@@ -164,12 +170,6 @@ private function shouldSkipNode(ClassMethod|Function_|Closure|ArrowFunction $nod
             return true;
         }
 
-        foreach ($node->params as $param) {
-            if (! $param->type instanceof Node) {
-                return true;
-            }
-        }
-
         if (! $node instanceof ClassMethod) {
             return false;
         }
@@ -203,7 +203,7 @@ private function collectActualReturnTypes(
         ClassMethod|Function_|Closure|ArrowFunction $node,
         array $returnStatements,
         bool $isAlwaysTerminating,
-    ): array {
+    ): ?array {
         if ($node instanceof ArrowFunction) {
             return [$this->getType($node->expr)];
         }
@@ -215,6 +215,12 @@ private function collectActualReturnTypes(
                 continue;
             }
 
+            $nativeReturnType = $this->nodeTypeResolver->getNativeType($returnStatement->expr);
+
+            if ($nativeReturnType instanceof MixedType) {
+                return null;
+            }
+
             $returnTypes[] = $this->getType($returnStatement->expr);
         }