fix #2243

TestSuite/generics40.pas

@@ -0,0 +1,22 @@
+var i: integer;
+type
+  t1<T> = class;
+  
+  t0 = class
+    
+    public function f1<T>: t1<T> := nil;
+    
+  end;
+  t1<T> = class(t0) end;
+  
+procedure p1<T>(q: t1<T>);
+begin
+  Inc(i);
+end;
+
+procedure p1(q: t0) := p1(q.f1&<byte>);
+
+begin
+  p1(new t0);
+  assert(i = 1);
+end.

TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs

@@ -2088,7 +2088,18 @@ namespace PascalABCCompiler.TreeConverter
                                                                                 is_alone_method_defined, syntax_tree_visitor.context, loc, syntax_nodes_parameters);
                         if (inst == null)
                         {
-                            set_of_possible_functions.RemoveAt(i);
+                            try
+                            {
+                                inst = generic_convertions.DeduceFunction(func, parameters, true, syntax_tree_visitor.context, loc, syntax_nodes_parameters);
+                            }
+                            catch
+                            {
+
+                            }
+                            if (inst == null)
+                                set_of_possible_functions.RemoveAt(i);
+                            else
+                                set_of_possible_functions[i] = inst;
                         }
                         else
                         {