diff --git a/NETGenerator/NETGenegratorTools.cs b/NETGenerator/NETGenegratorTools.cs
index 302c57456..730aa846d 100644
--- a/NETGenerator/NETGenegratorTools.cs
+++ b/NETGenerator/NETGenegratorTools.cs
@@ -229,16 +229,22 @@ namespace PascalABCCompiler.NETGenerator
             {
                 case TypeCode.Boolean:
                 case TypeCode.Byte:
+                    il.Emit(OpCodes.Ldind_U1);
+                    break;
                 case TypeCode.SByte:
                     il.Emit(OpCodes.Ldind_I1);
                     break;
                 case TypeCode.Char:
-                case TypeCode.Int16:
                 case TypeCode.UInt16:
+                    il.Emit(OpCodes.Ldind_U2);
+                    break;
+                case TypeCode.Int16:
                     il.Emit(OpCodes.Ldind_I2);
                     break;
-                case TypeCode.Int32:
                 case TypeCode.UInt32:
+                    il.Emit(OpCodes.Ldind_U4);
+                    break;
+                case TypeCode.Int32:
                     il.Emit(OpCodes.Ldind_I4);
                     break;
                 case TypeCode.Int64:
diff --git a/ParserTools/ParserTools/DefaultLanguageInformation.cs b/ParserTools/ParserTools/DefaultLanguageInformation.cs
index b21e8a545..160e641d5 100644
--- a/ParserTools/ParserTools/DefaultLanguageInformation.cs
+++ b/ParserTools/ParserTools/DefaultLanguageInformation.cs
@@ -1632,10 +1632,12 @@ namespace PascalABCCompiler.Parsers
             Dictionary<string, int> class_generic_table = new Dictionary<string, int>();
             ParameterInfo[] pis = scope.CompiledMethod.GetParameters();
             Type[] tt = scope.CompiledMethod.GetGenericArguments();
+            int gen_ind = 0;
             if (!scope.IsExtension)
                 sb.Append(GetShortTypeName(scope.CompiledMethod.DeclaringType));
             else
             {
+                gen_ind = 1;
                 generic_param_args = new Dictionary<string, string>();
                 for (int i = 0; i < pis.Length; i++)
                 {
@@ -1661,7 +1663,7 @@ namespace PascalABCCompiler.Parsers
             if (scope.CompiledMethod.GetGenericArguments().Length > 0)
             {
                 sb.Append('<');
-                for (int i = 1; i < tt.Length; i++)
+                for (int i = gen_ind; i < tt.Length; i++)
                 {
                     if (class_generic_table.ContainsKey(tt[i].Name))
                     {
diff --git a/TestSuite/arithm11.pas b/TestSuite/arithm11.pas
new file mode 100644
index 000000000..95131d5b3
--- /dev/null
+++ b/TestSuite/arithm11.pas
@@ -0,0 +1,52 @@
+procedure Test(b1: byte; var b2: byte);
+begin
+  assert(b1 < b2);
+end;
+procedure Test(b1: shortint; var b2: shortint);
+begin
+  assert(b1 < b2);
+end;
+procedure Test(b1: word; var b2: word);
+begin
+  assert(b1 < b2);
+end;
+procedure Test(b1: longword; var b2: longword);
+begin
+  assert(b1 < b2);
+end;
+procedure Test(b1: uint64; var b2: uint64);
+begin
+  assert(b1 < b2);
+end;
+begin
+  var b1, b2: byte;
+  b1 := 254;
+  b2 := 255;
+  Test(b1, b2);
+  var w1, w2: word;
+  w1 := word.MaxValue - 1;
+  w2 := word.MaxValue;
+  Test(w1, w2);
+  var s1, s2: word;
+  s1 := shortint.MaxValue - 1;
+  s2 := shortint.MaxValue;
+  Test(s1, s2);
+  var lw1, lw2: longword;
+  lw1 := longword.MaxValue - 1;
+  lw2 := longword.MaxValue;
+  Test(lw1, lw2);
+  var ui1, ui2: uint64;
+  ui1 := uint64.MaxValue - 1;
+  ui2 := uint64.MaxValue;
+  Test(ui1, ui2);
+  var arr: array of byte := (b1, b2);
+  Test(arr[0], arr[1]);
+  var arr2: array of word := (w1, w2);
+  Test(arr2[0], arr2[1]);
+  var arr3: array of longword := (lw1, lw2);
+  Test(arr3[0], arr3[1]);
+  var arr4: array of uint64 := (ui1, ui2);
+  Test(arr4[0], arr4[1]);
+  var arr5: array of shortint := (shortint.MaxValue-1, shortint.MaxValue);
+  Test(arr5[0], arr5[1]);
+end.
\ No newline at end of file
diff --git a/TestSuite/errors/err0214.pas b/TestSuite/errors/err0214.pas
new file mode 100644
index 000000000..656578542
--- /dev/null
+++ b/TestSuite/errors/err0214.pas
@@ -0,0 +1,11 @@
+type A = interface
+  function f: integer;
+end;
+
+B = class(A)
+  
+end;
+
+begin
+
+end.
\ No newline at end of file
diff --git a/TestSuite/errors/err0215.pas b/TestSuite/errors/err0215.pas
new file mode 100644
index 000000000..e67b87da1
--- /dev/null
+++ b/TestSuite/errors/err0215.pas
@@ -0,0 +1,10 @@
+type A = interface
+  function f: integer;
+  begin
+    
+  end;
+end;
+
+begin
+
+end.
\ No newline at end of file
diff --git a/TreeConverter/TreeConversion/syntax_tree_visitor.cs b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
index 01694867c..e33a8c8bd 100644
--- a/TreeConverter/TreeConversion/syntax_tree_visitor.cs
+++ b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
@@ -11833,6 +11833,15 @@ namespace PascalABCCompiler.TreeConverter
                     AddError(get_location(_function_header.where_defs), "WHERE_SECTION_MUST_BE_ONLY_IN_FIRST_DECLARATION");
                 }
             }
+            if (context.converted_type != null && context.converted_type.IsInterface)
+            {
+                if (body_exists)
+                {
+                    AddError(new InterfaceFunctionWithBody(get_location(_function_header)));
+                }
+                common_method_node cmnode = context.top_function as common_method_node;
+                context.set_virtual_abstract(cmnode);
+            }
             convertion_data_and_alghoritms.create_function_return_variable(context.top_function, si);
 
             /*if (_function_header.name != null && context.converted_compiled_type != null && context.top_function is common_namespace_function_node)