diff --git a/src/sly/lexer/attributes/ModesAttribute.cs b/src/sly/lexer/attributes/ModesAttribute.cs
deleted file mode 100644
index d464010d..00000000
--- a/src/sly/lexer/attributes/ModesAttribute.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-
-namespace sly.lexer
-{
-    [AttributeUsage(AttributeTargets.Enum)]
-    public class ModesAttribute : Attribute
-    {
-        
-        public IList<string> Modes { get; }
-
-        public ModesAttribute(params string[] modes)
-        {
-            Modes = modes.ToList();
-        }
-        
-    }
-}
\ No newline at end of file
diff --git a/src/sly/parser/generator/EBNFParserBuilder.cs b/src/sly/parser/generator/EBNFParserBuilder.cs
index 88dde194..5de6e0a5 100644
--- a/src/sly/parser/generator/EBNFParserBuilder.cs
+++ b/src/sly/parser/generator/EBNFParserBuilder.cs
@@ -111,25 +111,10 @@ protected override ISyntaxParser<IN, OUT> BuildSyntaxParser(ParserConfiguration<
             string rootRule)
         {
             ISyntaxParser<IN, OUT> parser = null;
-            switch (parserType)
+            if (parserType == ParserType.EBNF_LL_RECURSIVE_DESCENT)
             {
-                case ParserType.LL_RECURSIVE_DESCENT:
-                {
-                    parser = new RecursiveDescentSyntaxParser<IN, OUT>(conf, rootRule, I18N);
-                    break;
-                }
-                case ParserType.EBNF_LL_RECURSIVE_DESCENT:
-                {
-                    parser = new EBNFRecursiveDescentSyntaxParser<IN, OUT>(conf, rootRule, I18N);
-                    break;
-                }
-                default:
-                {
-                    parser = null;
-                    break;
-                }
+                parser = new EBNFRecursiveDescentSyntaxParser<IN, OUT>(conf, rootRule, I18N);
             }
-
             return parser;
         }
 
diff --git a/src/sly/parser/generator/ParserBuilder.cs b/src/sly/parser/generator/ParserBuilder.cs
index 62ebb377..832d13f8 100644
--- a/src/sly/parser/generator/ParserBuilder.cs
+++ b/src/sly/parser/generator/ParserBuilder.cs
@@ -14,9 +14,6 @@
 
 namespace sly.parser.generator
 {
-    public delegate BuildResult<Parser<IN, OUT>> ParserChecker<IN, OUT>(BuildResult<Parser<IN, OUT>> result,
-        NonTerminal<IN> nonterminal) where IN : struct;
-
     /// <summary>
     ///     this class provides API to build parser
     /// </summary>
@@ -280,7 +277,7 @@ private Rule<IN> BuildNonTerminal(Tuple<string, string> ntAndRule)
 
         private BuildResult<Parser<IN, OUT>> CheckParser(BuildResult<Parser<IN, OUT>> result)
         {
-            var checkers = new List<ParserChecker<IN, OUT>>
+            var checkers = new List<Func<BuildResult<Parser<IN, OUT>>,NonTerminal<IN>,BuildResult<Parser<IN, OUT>>>>
             {
                 CheckUnreachable,
                 CheckNotFound,
diff --git a/src/sly/parser/generator/visitor/mermaid/IMermaid.cs b/src/sly/parser/generator/visitor/mermaid/IMermaid.cs
index 1624c462..21f43dbe 100644
--- a/src/sly/parser/generator/visitor/mermaid/IMermaid.cs
+++ b/src/sly/parser/generator/visitor/mermaid/IMermaid.cs
@@ -1,4 +1,4 @@
-namespace sly.parser.generator.visitor.dotgraph
+namespace sly.parser.generator.visitor.mermaid
 {
     public interface IMermaid
     {
diff --git a/src/sly/parser/generator/visitor/mermaid/MermaidNode.cs b/src/sly/parser/generator/visitor/mermaid/MermaidNode.cs
index c0b687d4..6bca14ea 100644
--- a/src/sly/parser/generator/visitor/mermaid/MermaidNode.cs
+++ b/src/sly/parser/generator/visitor/mermaid/MermaidNode.cs
@@ -1,6 +1,7 @@
 using System.Text;
+using sly.parser.generator.visitor.dotgraph;
 
-namespace sly.parser.generator.visitor.dotgraph {
+namespace sly.parser.generator.visitor.mermaid {
     
     public enum MermaidNodeShape
     {
diff --git a/src/sly/parser/syntax/grammar/TerminalClause.cs b/src/sly/parser/syntax/grammar/TerminalClause.cs
index 4b7ab9de..5b3d8162 100644
--- a/src/sly/parser/syntax/grammar/TerminalClause.cs
+++ b/src/sly/parser/syntax/grammar/TerminalClause.cs
@@ -73,6 +73,7 @@ public string Dump()
         }
 
 
+        [ExcludeFromCodeCoverage]
         public bool Equals(IClause<T> clause)
         {
             if (clause is TerminalClause<T> other)
@@ -82,6 +83,8 @@ public bool Equals(IClause<T> clause)
 
             return false;
         }
+        
+        [ExcludeFromCodeCoverage]
         protected bool Equals(TerminalClause<T> other)
         {
             if (IsExplicitToken)
@@ -110,11 +113,8 @@ public IndentTerminalClause(IndentationType expectedIndentation, bool discard) :
             ExpectedIndentation = expectedIndentation;
             Discarded = discard;
         }
-    
-        public override  bool MayBeEmpty()
-        {
-            return false;
-        }
+
+        public override bool MayBeEmpty() => false;
     
         public override bool Check(Token<T> nextToken)
         {
diff --git a/src/sly/parser/syntax/tree/EmptyNode.cs b/src/sly/parser/syntax/tree/EmptyNode.cs
deleted file mode 100644
index 0f03eefa..00000000
--- a/src/sly/parser/syntax/tree/EmptyNode.cs
+++ /dev/null
@@ -1,25 +0,0 @@
-namespace sly.parser.syntax.tree;
-
-public class EmptyNode<IN> : ISyntaxNode<IN> where IN : struct
-{
-    public bool IsEpsilon => true;
-    public bool Discarded => false;
-    public string Name => "epsilon";
-
-
-    public bool HasByPassNodes
-    {
-        get { return false; } 
-        set { }
-    }
-
-    public string Dump(string tab)
-    {
-        return "epsilon";
-    }
-
-    public string ToJson(int index = 0)
-    {
-        return $@"""{index}.{Name} : {{}}";
-    }
-}
\ No newline at end of file