diff --git a/TreeConverter/TreeConversion/syntax_tree_visitor.cs b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
index 19c7a77d8..72d1e99f0 100644
--- a/TreeConverter/TreeConversion/syntax_tree_visitor.cs
+++ b/TreeConverter/TreeConversion/syntax_tree_visitor.cs
@@ -12110,7 +12110,7 @@ namespace PascalABCCompiler.TreeConverter
             }
             context.top_function.is_overload = true;                                       // SSM 12/08/15
             context.last_created_function.symbol_kind = symbol_kind.sk_overload_function;
-
+            bool is_forward = false;
             for (int i = 0; i < _procedure_attributes_list.proc_attributes.Count; i++)
             {
                 convertion_data_and_alghoritms.check_node_parser_error(_procedure_attributes_list.proc_attributes[i]);
@@ -12138,7 +12138,13 @@ namespace PascalABCCompiler.TreeConverter
                             {
                                 AddError(get_location(_procedure_attributes_list.proc_attributes[i]), "ATTRIBUTES_IN_INTERFACE_MEMBER");
                             }
+                            common_namespace_function_node top_function = context.top_function as common_namespace_function_node;
+                            if (top_function != null && top_function.ConnectedToType != null)
+                            {
+                                AddError(get_location(_procedure_attributes_list.proc_attributes[i]), "FORWARD_EXTENSION_METHODS_NOT_ALLOWED");
+                            }
 
+                            is_forward = true;
                             break;
                         }
                     case SyntaxTree.proc_attribute.attr_virtual:
@@ -12288,6 +12294,8 @@ namespace PascalABCCompiler.TreeConverter
                 		}
                     case proc_attribute.attr_extension:
                         {
+                            if (is_forward)
+                                AddError(get_location(_procedure_attributes_list), "EXTENSIONMETHOD_KEYWORD_NOT_ALLOWED");
                             if (context.converted_compiled_type != null)
                                 AddError(get_location(_procedure_attributes_list), "EXTENSIONMETHOD_KEYWORD_NOT_ALLOWED");
                             if (in_interface_part)
diff --git a/bin/Lng/Eng/SemanticErrors_ib.dat b/bin/Lng/Eng/SemanticErrors_ib.dat
index 61ca02b6c..5eb384dce 100644
--- a/bin/Lng/Eng/SemanticErrors_ib.dat
+++ b/bin/Lng/Eng/SemanticErrors_ib.dat
@@ -120,6 +120,7 @@ INTERFACE_EXPECTED=Interface expected
 IMPLICIT_EXPLICIT_OPERATOR_EXTENSION_ONLY_FOR_COMPILED_CLASSES_ALLOWED=Operators implicit and explicit can be extended only for classes from another .NET assemblies
 EXTENSIONMETHOD_KEYWORD_NOT_ALLOWED=extensionmethod is not allowed in this context
 CANNOT_EXTEND_STANDARD_OPERATORS_FOR_DELEGATE=Can not extend operators +,+=,-,-= for delegates
+FORWARD_EXTENSION_METHODS_NOT_ALLOWED=forward attribute can not be applied to extension methods
 %PREFIX%=COMPILATIONERROR_
 UNIT_MODULE_EXPECTED_LIBRARY_FOUND=Unit expected, library found
 ASSEMBLY_{0}_READING_ERROR=Error by reading assembly '{0}'
diff --git a/bin/Lng/Rus/SemanticErrors_ib.dat b/bin/Lng/Rus/SemanticErrors_ib.dat
index 2ecffbb38..86f0d460b 100644
--- a/bin/Lng/Rus/SemanticErrors_ib.dat
+++ b/bin/Lng/Rus/SemanticErrors_ib.dat
@@ -115,6 +115,7 @@ INTERFACE_EXPECTED=Ожидался интерфейс
 IMPLICIT_EXPLICIT_OPERATOR_EXTENSION_ONLY_FOR_COMPILED_CLASSES_ALLOWED=extension-операторы преобразования типов допустимы только для классов из других сборок .NET
 EXTENSIONMETHOD_KEYWORD_NOT_ALLOWED=Атрибут extensionmethod недопустим в данном контексте
 CANNOT_EXTEND_STANDARD_OPERATORS_FOR_DELEGATE=Нельзя раширять операции +,+=,-,-= для делегатов
+FORWARD_EXTENSION_METHODS_NOT_ALLOWED=Атрибут forward недопустим для методов расширения
 %PREFIX%=COMPILATIONERROR_
 UNIT_MODULE_EXPECTED_LIBRARY_FOUND=Ожидался модуль, а встречена библиотека
 ASSEMBLY_{0}_READING_ERROR=Ошибка при чтении сборки '{0}'