diff --git a/src/org/rascalmpl/library/ParseTree.rsc b/src/org/rascalmpl/library/ParseTree.rsc
index eccd3bf4d5f..9f50ba8a83a 100644
--- a/src/org/rascalmpl/library/ParseTree.rsc
+++ b/src/org/rascalmpl/library/ParseTree.rsc
@@ -365,7 +365,6 @@ bool subtype(\lexical(_), Symbol::\adt("Tree", [])) = true;
 bool subtype(\layout(_), Symbol::\adt("Tree", [])) = true;
 bool subtype(\keyword(_), Symbol::\adt("Tree", [])) = true;
 
-bool subtype(\data(parameter(_,_)), adt(_,_))                   = true;
 bool subtype(\syntax(parameter(_,_)), sort(_))                  = true;
 bool subtype(\syntax(parameter(_,_)), \parameterized-sort(_,_)) = true;
 bool subtype(\lexical(parameter(_,_)), lex(_))                  = true;
diff --git a/src/org/rascalmpl/semantics/dynamic/SyntaxRoleModifier.java b/src/org/rascalmpl/semantics/dynamic/SyntaxRoleModifier.java
index cfc5ea55a80..83189743676 100644
--- a/src/org/rascalmpl/semantics/dynamic/SyntaxRoleModifier.java
+++ b/src/org/rascalmpl/semantics/dynamic/SyntaxRoleModifier.java
@@ -12,7 +12,6 @@
 *******************************************************************************/
 package org.rascalmpl.semantics.dynamic;
 
-import org.rascalmpl.ast.Name;
 import org.rascalmpl.interpreter.IEvaluator;
 import org.rascalmpl.interpreter.env.Environment;
 import org.rascalmpl.interpreter.result.Result;
diff --git a/src/org/rascalmpl/types/ModifySyntaxRole.java b/src/org/rascalmpl/types/ModifySyntaxRole.java
index ae3b0a907d9..d382a14285d 100644
--- a/src/org/rascalmpl/types/ModifySyntaxRole.java
+++ b/src/org/rascalmpl/types/ModifySyntaxRole.java
@@ -112,6 +112,11 @@ public Syntax(Type arg) {
             super(arg);
         }
 
+        @Override
+        public String toString() {
+            return "syntax[" + arg.toString() + "]";
+        }
+
         @Override
         public IConstructor asSymbol(IValueFactory vf, TypeStore store, ISetWriter grammar, Set<IConstructor> done) {
             return vf.constructor(RascalValueFactory.Symbol_SyntaxModifier, arg.asSymbol(vf, store, grammar, done));
@@ -153,6 +158,20 @@ public boolean isSubtypeOfSyntaxModifier(RascalType type) {
             return type instanceof Syntax;
         }
 
+        @Override
+        protected boolean isSupertypeOf(RascalType type) {
+            assert isOpen();
+
+            if (type instanceof NonTerminalType) {
+                 NonTerminalType nt = (NonTerminalType) type;
+                 IConstructor sym = nt.getSymbol();
+
+                 return SymbolAdapter.isSort(sym) || SymbolAdapter.isParameterizedSort(sym);
+            }
+
+            return false;
+        }
+
         @Override
         public boolean isSubtypeOfNonTerminal(RascalType type) {
             assert isOpen(); // otherwise we wouldn't be here 
@@ -248,6 +267,25 @@ public Lexical(Type arg) {
             super(arg);
         }
 
+        @Override
+        public String toString() {
+            return "lexical[" + arg.toString() + "]";
+        }
+
+        @Override
+        protected boolean isSupertypeOf(RascalType type) {
+            assert isOpen();
+
+            if (type instanceof NonTerminalType) {
+                 NonTerminalType nt = (NonTerminalType) type;
+                 IConstructor sym = nt.getSymbol();
+
+                 return SymbolAdapter.isLex(sym) || SymbolAdapter.isParameterizedLex(sym);
+            }
+
+            return false;
+        }
+
         @Override
         public boolean isSubtypeOfSyntaxModifier(RascalType type) {
             assert isOpen();
@@ -382,12 +420,32 @@ public Layout(Type arg) {
             super(arg);
         }
 
+        @Override
+        public String toString() {
+            return "layout[" + arg.toString() + "]";
+        }
+
         @Override
         public boolean isSubtypeOfSyntaxModifier(RascalType type) {
             assert isOpen();
             return type instanceof Layout;
         }
 
+        @Override
+        protected boolean isSupertypeOf(RascalType type) {
+            assert isOpen();
+
+            if (type instanceof NonTerminalType) {
+                 NonTerminalType nt = (NonTerminalType) type;
+                 IConstructor sym = nt.getSymbol();
+
+                 return SymbolAdapter.isLayouts(sym);
+            }
+
+            return false;
+        }
+
+
         @Override
         protected Type lubWithModifySyntax(RascalType type) {
             if (type instanceof Syntax) {
@@ -516,6 +574,11 @@ public Keyword(Type arg) {
             super(arg);
         }
 
+        @Override
+        public String toString() {
+            return "keyword[" + arg.toString() + "]";
+        }
+
         @Override
         public IConstructor asSymbol(IValueFactory vf, TypeStore store, ISetWriter grammar, Set<IConstructor> done) {
             return vf.constructor(RascalValueFactory.Symbol_KeywordModifier, arg.asSymbol(vf, store, grammar, done));
@@ -552,6 +615,17 @@ protected Type glbWithModifySyntax(RascalType type) {
             return tf.voidType();
         }
 
+        @Override
+        protected boolean isSupertypeOf(RascalType type) {
+            if (type instanceof NonTerminalType) {
+                 NonTerminalType nt = (NonTerminalType) type;
+                 IConstructor sym = nt.getSymbol();
+
+                 return SymbolAdapter.isKeyword(sym);
+            }
+
+            return false;
+        }
 
         @Override
         public boolean isSubtypeOfSyntaxModifier(RascalType type) {
@@ -644,12 +718,24 @@ public Data(Type arg) {
             super(arg);
         }
 
+        @Override
+        public String toString() {
+            return "data[" + arg.toString() + "]";
+        }
+
         @Override
         public boolean isSubtypeOfSyntaxModifier(RascalType type) {
             assert isOpen();
             return type instanceof Data;
         }
 
+         @Override
+        protected boolean isSupertypeOf(RascalType type) {
+            assert isOpen();
+            // Here is it essential that {@link NonTerminalType#isAbstractData()} returns true.
+            return type.isAbstractData(); 
+        }
+
         @Override
         protected Type lubWithModifySyntax(RascalType type) {
             if (type instanceof Syntax) {
@@ -770,6 +856,11 @@ protected Type glbWithAbstractData(Type type) {
         }
     }
 
+    @Override
+    public boolean isOpen() {
+        return arg.isOpen();
+    }
+    
     @Override
     protected Type lubWithAbstractData(Type type) {
         // this is for all the syntax roles that are not data. Data overrides this
@@ -787,9 +878,7 @@ protected Type glbWithAbstractData(Type type) {
 	}
 
     @Override
-    protected boolean isSupertypeOf(RascalType type) {
-        return type.isSubtypeOfSyntaxModifier(this);
-    }
+    abstract protected boolean isSupertypeOf(RascalType type);
 
     @Override
     protected boolean isSubtypeOfNode(Type type) {
@@ -835,6 +924,9 @@ public Type asAbstractDataType() {
     @Override
     abstract public boolean match(Type matched, Map<Type, Type> bindings) throws FactTypeUseException;
 
+    @Override
+    abstract public String toString();
+
     @Override
     public IValue randomValue(Random random, IValueFactory vf, TypeStore store, Map<Type, Type> typeParameters,
         int maxDepth, int maxBreadth) {