diff --git a/tests/Core/File/GetMethodPropertiesTest.inc b/tests/Core/File/GetMethodPropertiesTest.inc
index b04202fcd2..c268ece3a9 100644
--- a/tests/Core/File/GetMethodPropertiesTest.inc
+++ b/tests/Core/File/GetMethodPropertiesTest.inc
@@ -73,3 +73,10 @@ class ReturnMe {
         return $this;
     }
 }
+
+/* testPHP8MixedTypeHint */
+function mixedTypeHint() :mixed {}
+
+/* testPHP8MixedTypeHintNullable */
+// Intentional fatal error - nullability is not allowed with mixed, but that's not the concern of the method.
+function mixedTypeHintNullable(): ?mixed {}
diff --git a/tests/Core/File/GetMethodPropertiesTest.php b/tests/Core/File/GetMethodPropertiesTest.php
index b801962637..36d57e7301 100644
--- a/tests/Core/File/GetMethodPropertiesTest.php
+++ b/tests/Core/File/GetMethodPropertiesTest.php
@@ -406,6 +406,52 @@ public function testReturnTypeStatic()
     }//end testReturnTypeStatic()
 
 
+    /**
+     * Test a function with return type "mixed".
+     *
+     * @return void
+     */
+    public function testPHP8MixedTypeHint()
+    {
+        $expected = [
+            'scope'                => 'public',
+            'scope_specified'      => false,
+            'return_type'          => 'mixed',
+            'nullable_return_type' => false,
+            'is_abstract'          => false,
+            'is_final'             => false,
+            'is_static'            => false,
+            'has_body'             => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testPHP8MixedTypeHint()
+
+
+    /**
+     * Test a function with return type "mixed" and nullability.
+     *
+     * @return void
+     */
+    public function testPHP8MixedTypeHintNullable()
+    {
+        $expected = [
+            'scope'                => 'public',
+            'scope_specified'      => false,
+            'return_type'          => '?mixed',
+            'nullable_return_type' => true,
+            'is_abstract'          => false,
+            'is_final'             => false,
+            'is_static'            => false,
+            'has_body'             => true,
+        ];
+
+        $this->getMethodPropertiesTestHelper('/* '.__FUNCTION__.' */', $expected);
+
+    }//end testPHP8MixedTypeHintNullable()
+
+
     /**
      * Test helper.
      *