aspect PredefinedTypes {
  // Define the NTA
  syn lazy List Program.getPredefinedTypeList() {
  return new List().
    add(new UnknownDecl("$unknown")).
    add(new PrimitiveDecl("boolean"));
  }
    
  // Broadcast the predefined types to useful places in the AST
  syn lazy PrimitiveDecl Program.booleanType() = (PrimitiveDecl) localLookup("boolean");
  eq Program.getBlock().booleanType() = booleanType();
  eq Program.getPredefinedType().booleanType() = booleanType();
  inh PrimitiveDecl BooleanLiteral.booleanType();
  inh PrimitiveDecl WhileStmt.booleanType();
  inh PrimitiveDecl Decl.booleanType();
}