Downgrade UndefinedMethod to PossiblyUndefinedMethod issue when one type has __call defined

src/Psalm/Checker/Statements/Expression/Call/MethodCallChecker.php

@@ -267,6 +267,8 @@ class MethodCallChecker extends \Psalm\Checker\Statements\Expression\CallChecker
                             $statements_checker->getSource()
                         )
                     ) {
+                        $has_valid_method_call_type = true;
+                        $existent_method_ids[] = $method_id;
                         $return_type = Type::getMixed();
                         continue;
                     }

tests/MethodCallTest.php

@@ -91,6 +91,20 @@ class MethodCallTest extends TestCase
                     $a = new A;
                     $a->bar();',
             ],
+            'canBeCalledOnMagic' => [
+                '<?php
+                    class A {
+                      public function __call(string $method) {}
+                    }
+
+                    class B {}
+
+                    $a = rand(0, 1) ? new A : new B;
+
+                    $a->maybeUndefinedMethod();',
+                'assertions' => [],
+                'error_levels' => ['PossiblyUndefinedMethod'],
+            ],
         ];
     }