diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/HighOrderFunctionArgHandler.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/HighOrderFunctionArgHandler.php
index 3d1a51c4e..14a947f51 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/HighOrderFunctionArgHandler.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/HighOrderFunctionArgHandler.php
@@ -288,7 +288,8 @@ final class HighOrderFunctionArgHandler
         }
 
         foreach ($container_param->type->getAtomicTypes() as $a) {
-            if (($a instanceof TClosure || $a instanceof TCallable) && !$a->params) {
+            // must check null explicitly, since no params (empty array) would not be handled correctly otherwise
+            if (($a instanceof TClosure || $a instanceof TCallable) && $a->params === null) {
                 return false;
             }
 
diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
index 2b73d6550..b24166f9c 100644
--- a/tests/FunctionCallTest.php
+++ b/tests/FunctionCallTest.php
@@ -2352,6 +2352,18 @@ class FunctionCallTest extends TestCase
                     fooFoo("string");',
                 'error_message' => 'InvalidScalarArgument',
             ],
+            'invalidArgumentCallableWithoutArgsUnion' => [
+                'code' => '<?php
+                    function foo(int $a): void {}
+
+                    /**
+                     * @param callable()|float $callable
+                     * @return void
+                     */
+                    function acme($callable) {}
+                    acme("foo");',
+                'error_message' => 'InvalidArgument',
+            ],
             'invalidArgumentWithDeclareStrictTypes' => [
                 'code' => '<?php declare(strict_types=1);
                     function fooFoo(int $a): void {}