[Downgrade PHP 7.0] Add string retype on object

rules-tests/DowngradePhp70/Rector/FunctionLike/DowngradeScalarTypeDeclarationRector/Fixture/fixture.php.inc

@@ -22,6 +22,9 @@ class Fixture
      */
     public function run($value)
     {
+        if (is_object($value)) {
+            $value = (string) $value;
+        }
     }
 }
 

rules-tests/DowngradePhp70/Rector/FunctionLike/DowngradeScalarTypeDeclarationRector/Fixture/object_stringable_param.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\Tests\DowngradePhp70\Rector\FunctionLike\DowngradeScalarTypeDeclarationRector\Fixture;
+
+final class ObjectStringableParam
+{
+    public function hasDefinition(string $id)
+    {
+        return $this->definitions[$id];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DowngradePhp70\Rector\FunctionLike\DowngradeScalarTypeDeclarationRector\Fixture;
+
+final class ObjectStringableParam
+{
+    /**
+     * @param string $id
+     */
+    public function hasDefinition($id)
+    {
+        if (is_object($id)) {
+            $id = (string) $id;
+        }
+        return $this->definitions[$id];
+    }
+}
+
+?>

rules/DowngradePhp70/Rector/FunctionLike/DowngradeScalarTypeDeclarationRector.php

@@ -5,8 +5,13 @@
 namespace Rector\DowngradePhp70\Rector\FunctionLike;
 
 use PhpParser\Node;
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Expr\Cast\String_;
+use PhpParser\Node\Expr\Variable;
 use PhpParser\Node\Stmt\ClassMethod;
+use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\Function_;
+use PhpParser\Node\Stmt\If_;
 use PHPStan\Type\BooleanType;
 use PHPStan\Type\FloatType;
 use PHPStan\Type\IntegerType;
@@ -84,6 +89,20 @@ public function refactor(Node $node): ?Node
                 $node,
                 [StringType::class, IntegerType::class, BooleanType::class, FloatType::class]
             );
+
+            $paramType = $this->getStaticType($param);
+            if ($paramType instanceof StringType) {
+                // add possible object with __toString() re-type to keep original behavior
+                // @see https://twitter.com/VotrubaT/status/1390974218108538887
+
+                /** @var string $variableName */
+                $variableName = $this->getName($param->var);
+
+                $if = $this->createObjetVariableStringCast($variableName);
+                $node->stmts = array_merge([$if], (array) $node->stmts);
+
+                return $node;
+            }
         }
 
         if (! $this->phpDocFromTypeDeclarationDecorator->decorateReturn($node)) {
@@ -92,4 +111,15 @@ public function refactor(Node $node): ?Node
 
         return $node;
     }
+
+    private function createObjetVariableStringCast(string $variableName): If_
+    {
+        $variable = new Variable($variableName);
+        $isObjectFuncCall = $this->nodeFactory->createFuncCall('is_object', [$variable]);
+
+        $if = new If_($isObjectFuncCall);
+        $assign = new Assign($variable, new String_($variable));
+        $if->stmts[] = new Expression($assign);
+        return $if;
+    }
 }

tests/Issues/Fixture/coariant_mixture.php.inc

@@ -24,6 +24,9 @@ final class CoriantMixture
      */
     private function parseArgument($token, array $all)
     {
+        if (is_object($token)) {
+            $token = (string) $token;
+        }
         reset($all);
         if (($inputArgument = isset($all[$key = key($all)]) ? $all[$key = key($all)] : null) && 'command' === $inputArgument->getName()) {
         }

tests/Issues/Fixture/input_interface.php.inc

@@ -53,6 +53,9 @@ class ArgvInput extends Input
      */
     private function parseArgument($token, array $all)
     {
+        if (is_object($token)) {
+            $token = (string) $token;
+        }
         reset($all);
         if (($inputArgument = isset($all[$key = key($all)]) ? $all[$key = key($all)] : null) && 'command' === $inputArgument->getName()) {
         }