diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
index 9ed9e6d313d..8b9483599fe 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/CallAnalyzer.php
@@ -707,7 +707,9 @@ private static function evaluateAribitraryParam(
             if (!$context->hasVariable($var_id, $statements_analyzer)
                 || $context->vars_in_scope[$var_id]->isNull()
             ) {
-                if (!isset($context->vars_in_scope[$var_id])) {
+                if (!isset($context->vars_in_scope[$var_id])
+                    && $arg->value instanceof PhpParser\Node\Expr\Variable
+                ) {
                     if (IssueBuffer::accepts(
                         new PossiblyUndefinedVariable(
                             'Variable ' . $var_id
diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 3e8df55d62e..e1af742417a 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -524,6 +524,17 @@ public function give(): void{
                         }
                     }',
             ],
+            'unknownMethodCallWithProperty' => [
+                '<?php
+                    class A {
+                        private string $b = "c";
+
+                        public function passesByRef(object $a): void {
+                            /** @psalm-suppress MixedMethodCall */
+                            $a->passedByRef($this->b);
+                        }
+                    }',
+            ],
         ];
     }