I'm building a new font based on a previous design. The previous font had a y.alt glyph, but the new one doesn't. I've removed the y.alt glyph, and have done my best to find and remove all reference to this glyph in the OT features, but when I try to compile the features I get an error saying the y.alt glyph is missing.

Is there a way to search the entire file for any reference to y.alt? I've looked everywhere and can't seem to find what's causing the error.