fix #2289

Configuration/GlobalAssemblyInfo.cs

@@ -15,7 +15,7 @@ internal static class RevisionClass
 	public const string Major = "3";
 	public const string Minor = "6";
 	public const string Build = "3";
-	public const string Revision = "2616";
+	public const string Revision = "2617";
 
         public const string MainVersion = Major + "." + Minor;
 	public const string FullVersion = Major + "." + Minor + "." + Build + "." + Revision;

Configuration/Version.defs

@@ -1,4 +1,4 @@
-%COREVERSION%=3
-%REVISION%=2616
 %MINOR%=6
+%REVISION%=2617
+%COREVERSION%=3
 %MAJOR%=3

Release/pabcversion.txt

@@ -1 +1 @@
-3.6.3.2616
+3.6.3.2617

ReleaseGenerators/PascalABCNET_version.nsh

@@ -1 +1 @@
-!define VERSION '3.6.3.2616'
+!define VERSION '3.6.3.2617'

TestSuite/class_interf.pas

@@ -0,0 +1,18 @@
+type
+  i1 = interface 
+    procedure p;
+  end;
+  
+  c1 = abstract class(i1) 
+  public
+    procedure p;
+    begin
+      Assert(111=111);
+    end;
+  end;
+  c2 = sealed class(c1) end;
+  
+begin
+  var a := new c2 as i1;
+  a.P
+end.

TreeConverter/TreeConversion/convertion_data_and_alghoritms.cs

@@ -1561,6 +1561,16 @@ namespace PascalABCCompiler.TreeConverter
             return eq_type_nodes(tn1, tn2, false);
         }
 
+        public static bool type_or_base_type_implements_interface(type_node tn, type_node interf)
+        {
+            do {
+                if (tn.ImplementingInterfaces.Contains(interf))
+                    return true;
+                tn = tn.base_type;
+            } while (tn != null);
+            return false;
+        }
+
         //Этот метод сверяет не только параметры, но и возвращаемое значение
         public static bool function_eq_params_and_result(function_node left, function_node right, bool weak = false)
         {

TreeConverter/TreeConversion/syntax_tree_visitor.cs

@@ -3066,6 +3066,7 @@ namespace PascalABCCompiler.TreeConverter
             weak_node_test_and_visit(_interface_node.interface_definitions);
         }
 
+
         public override void visit(SyntaxTree.typecast_node node)
         {
 
@@ -3093,7 +3094,9 @@ namespace PascalABCCompiler.TreeConverter
                 {
                     AddError(loc, "EXPECTED_DERIVED_CLASSES");
                 }
-            if (en.type.IsSealed && tp.IsInterface && !en.type.ImplementingInterfaces.Contains(tp))
+            if (en.type.IsSealed && tp.IsInterface && /*!en.type.ImplementingInterfaces.Contains(tp)*/
+                !convertion_data_and_alghoritms.type_or_base_type_implements_interface(en.type,tp)
+                )
             {
                 AddError(loc, "CAN_NOT_CONVERT_TYPE_{0}_TO_INTERFACE_{1}", en.type.PrintableName, tp.PrintableName);
             }