T4 error: Compiling transformation: Invalid token 'this' in class, struct, or interface member

If you have a T4 Template .tt file that throws a weird Compiling transformation: Invalid token 'this' in class, struct, or interface member error that seems to come out of nowhere, try to delete extraneous spaces.

In my case, I has copied/pasted the .tt content from a web page and I was trying to understand why it wouldn't work. I right clicked on the source, went to Advanced, chose Convert all spaces to tabs, then back to Convert all tabs to spaces. Then it worked. I guess some white spaces where not really spaces or some other formatting issue.

If you don't have the options when you right click, it might be that they are features of the Tangible T4 Editor.