[tex-k] mf.ch Issue

[Karl Berry]

Tim, thank you very much for the report. I'm very impressed that you
found this! How did you discover it? Are you actually using Metafont to
the extent of examining precise pixel output?

    I suspect this is not intentional.

You're right that it's not intentional. (Based on the formatting of the
code, I think I'm the one who made that change, 30+ years ago. I even
very vaguely remember it coming up.)

I am somewhat surprised that the trap test did not catch this mistake.
I'll investigate and perhaps report that to Knuth.

I suspect the problem with limited preprocessor argument lengths is long
gone. I'll try eliminating the change and we'll see. --thanks much, karl.