visual studio 2013 - T4 reports Compiling transformation: Invalid token 'this' in class, struct -

attempting run t4 templates immutable object graph gives errors of

╔═══════╦═══╦══════════════════════════════════════════════════════════════════════════════════════════════════╦═════════════════════════════════════════════════════════╦═══╦════╦══════╗ ║ error ║ 5 ║ compiling transformation: invalid token 'this' in class, struct, or interface member declaration ║ c:\dev\immutableobjectgraph-master\2013\demo\message.tt ║ 1 ║  1 ║ demo ║ ║ error ║ 6 ║ compiling transformation: method must have return type                                         ║ c:\dev\immutableobjectgraph-master\2013\demo\message.tt ║ 1 ║  6 ║ demo ║ ║ error ║ 7 ║ compiling transformation: type expected                                                          ║ c:\dev\immutableobjectgraph-master\2013\demo\message.tt ║ 1 ║ 12 ║ demo ║ ╚═══════╩═══╩══════════════════════════════════════════════════════════════════════════════════════════════════╩═════════════════════════════════════════════════════════╩═══╩════╩══════╝ 

the line reported line 1, , full set of t4 templates many hundreds of lines. how troubleshoot , fix issue?

you cannot have literals in t4 template after scriptlet.

change

<#@ template debug="true" language="c#" #> <#+ // scriptlet #>                                               <-- empty line here 

to

<#@ template debug="true" language="c#" #> <#+ // scriptlet #> 

debugging

you can see c# being generated t4 engine calling preprocesstemplate custom templating host.

i modified custom template host sample purpose:

using microsoft.visualstudio.texttemplating; using system; using system.codedom.compiler; using system.collections.generic; using system.io; using system.text;  namespace customhost {     class customcmdlinehost : itexttemplatingenginehost     {         public string templatefile { get; private set; }         public string fileextension { get; private set; }         public encoding fileencoding { get; private set; }         public compilererrorcollection errors { get; private set; }          public ilist<string> standardassemblyreferences { { return new[] { typeof(system.uri).assembly.location }; } }         public ilist<string> standardimports { { return new string[] { "system" }; } }          public customcmdlinehost(string file)         {             this.templatefile = file;             this.fileencoding = encoding.utf8;             this.fileextension = ".txt";         }          public bool loadincludetext(string requestfilename, out string content, out string location)         {             content = location = string.empty;              if (file.exists(requestfilename))             {                 content = file.readalltext(requestfilename);                 return true;             }              return false;         }          public object gethostoption(string optionname)         {             object returnobject;             switch (optionname)             {                 case "cacheassemblies":                     returnobject = true;                     break;                 default:                     returnobject = null;                     break;             }             return returnobject;         }          public string resolveassemblyreference(string assemblyreference)         {             return resolvepath(assemblyreference);         }          public type resolvedirectiveprocessor(string processorname)         {             throw new exception("directive processor not found");         }          public string resolvepath(string filename)         {             if (file.exists(filename))             {                 return filename;             }              string candidate = path.combine(path.getdirectoryname(this.templatefile), filename);             if (file.exists(candidate))             {                 return candidate;             }              return filename;         }          public string resolveparametervalue(string directiveid, string processorname, string parametername)         {             return string.empty;         }          public void setfileextension(string extension)         {             fileextension = extension;         }          public void setoutputencoding(system.text.encoding encoding, bool fromoutputdirective)         {             fileencoding = encoding;         }          public void logerrors(compilererrorcollection errors)         {             errors = errors;         }          public appdomain providetemplatingappdomain(string content)         {             return appdomain.createdomain("generation app domain");         }     }      class program     {         static void main(string[] args)         {             var templatefilename = args[0];              customcmdlinehost host = new customcmdlinehost(templatefilename);             engine engine = new engine();              string language;             string[] refs;             var output = engine.preprocesstemplate(                 // input file                 file.readalltext(templatefilename), host,                 "testclass", "testnamespace", out language, out refs);              string outputfilename = path.combine(                 path.getdirectoryname(templatefilename),                 templatefilename + ".generator.cs");              file.writealltext(outputfilename, output, host.fileencoding);              foreach (compilererror error in host.errors)                 console.writeline(error.tostring());              console.readline();         }     } } 

examining transformer generated template showed lines following outside transformtext() method. seemingly, literals in source templates came after scriptlet (<#+ #>) placed in-fix generated generator class.

        #line 1 "c:\dev\immutableobjectgraph-master\2013\demo\fruit.tt" this.write("\n"); 

removing newline characters @ end of each template file resolved issue.