diff --git a/TestSuite/errors/err0517_as_generic_parameter.pas b/TestSuite/errors/err0517_as_generic_parameter.pas
new file mode 100644
index 000000000..9dfd2ec9a
--- /dev/null
+++ b/TestSuite/errors/err0517_as_generic_parameter.pas
@@ -0,0 +1,9 @@
+//!Операция as не может быть применена к обобщённому параметру T, не имеющему спецификатора "class"
+type
+  A<T> = class
+    public static procedure Test(x: T) := Print(x as T);
+  end;
+
+begin
+  A&<integer>.Test(2); // выводит мусор
+end.
diff --git a/TreeConverter/TreeConversion/syntax_tree_visitor.cs b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
index 05f3a050c..bd7647141 100644
--- a/TreeConverter/TreeConversion/syntax_tree_visitor.cs
+++ b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
@@ -3179,7 +3179,7 @@ namespace PascalABCCompiler.TreeConverter
             }
             else
             {
-                if (tp.is_generic_parameter && !tp.is_class && !(tp.base_type != null && tp.base_type.is_class) && !(tp.base_type != null && tp.base_type.original_generic != null && tp.base_type.original_generic.is_class))
+                if (tp.is_generic_parameter && !tp.is_class && !(tp.base_type != null && tp.base_type.is_class && tp.base_type != SystemLibrary.SystemLibrary.object_type) && !(tp.base_type != null && tp.base_type.original_generic != null && tp.base_type.original_generic.is_class))
                     AddError(get_location(node.type_def), "OPERATOR_AS_CAN_NOT_BE_USED_WITH_GENERIC_PARAMETER_{0}_WITHOUT_CLASS_CONSTRAINT", tp.name);
                 if (tp.is_value_type)
                     AddError(get_location(node.type_def), "OPERATOR_AS_MUST_BE_USED_WITCH_A_REFERENCE_TYPE_VALUETYPE{0}", tp.PrintableName);