Why am I getting "Error -1,752" when trying to save in Script Editor?

The problem is that the file is a plain text file. When I originally created the file in 2007, Script Editor could apparently save uncompiled .scpt files. Now, however, as described in Can't save AppleScript file when created by touch, .scpt files must be compiled. Uncompiled files can be saved with the .applescript extension.

I know this is nearly a duplicate of the question linked above, but I added it because as of OS X 10.11 El Capitan Script Editor gives an error number for this problem. I couldn't find any other references to this error number so I thought it was worthwhile to get the error number in a question title.