diff --git a/TestSuite/Deconstructs2.pas b/TestSuite/Deconstructs2.pas
new file mode 100644
index 000000000..d47b21bf0
--- /dev/null
+++ b/TestSuite/Deconstructs2.pas
@@ -0,0 +1,16 @@
+var i: integer;
+type
+  t1 = class
+    procedure Deconstruct;
+    begin
+      i := 1;
+    end;
+  end;
+  
+begin
+  if new t1 is t1(var a) then
+    begin
+      i := 2;
+    end;
+  assert(i = 2);
+end.
\ No newline at end of file
diff --git a/TreeConverter/TreeConversion/SyntaxTreeVisitorNodes/Patterns.cs b/TreeConverter/TreeConversion/SyntaxTreeVisitorNodes/Patterns.cs
index 99dc7da6f..18cdb615d 100644
--- a/TreeConverter/TreeConversion/SyntaxTreeVisitorNodes/Patterns.cs
+++ b/TreeConverter/TreeConversion/SyntaxTreeVisitorNodes/Patterns.cs
@@ -93,6 +93,8 @@ namespace PascalABCCompiler.TreeConverter
             out type_node[] parameterTypes)
         {
             parameterTypes = new type_node[givenParameterTypes.Length];
+            if (candidate.parameters.Count == 0)
+                return false;
             candidate.parameters[0].name = "Self"; // SSM 23.06.20 #2268 - это если в NET где-то такое нашли
             var selfParameter = candidate.is_extension_method ? candidate.parameters.FirstOrDefault(IsSelfParameter) : null;
             Debug.Assert(!candidate.is_extension_method || selfParameter != null, "Couldn't find self parameter in extension method");