"After a series of "@", "(", or ")" and a capital letter, the tail shifts up"

[davelab6]

Did you get the font from Google Fonts? Then please head over to
https://github.com/google/fonts/issues
and file an issue with Google Fonts.
If not, REMOVE THIS PARAGRAPH BEFORE FILING YOUR ISSUE.

Well, I am coming from Google Fonts with google/fonts#7258 to say this is probably an upstream issue ;)

Describe the bug

"After a series of "@", "(", or ")" and a capital letter, the tail shifts up"

To Reproduce
Type **************?

Expected behavior
Case feature works more as expected

Screenshots
See GF issue

[rsms]

Although not great, this is the expected behavior and technically not a bug.

This happens because calt substitution can only cause an infinite forward cascade, but requires explicit substitution for back-propagation.

Inter has rules for up to 5 backwards substitutions:

inter/src/features/calt.fea

Lines 267 to 271 in 4f3d79f

	sub @CASE_L' @UC by @CASE_R;
	sub @CASE_L' @CASE_L @UC by @CASE_R;
	sub @CASE_L' @CASE_L @CASE_L @UC by @CASE_R;
	sub @CASE_L' @CASE_L @CASE_L @CASE_L @UC by @CASE_R;
	sub @CASE_L' @CASE_L @CASE_L @CASE_L @CASE_L @UC by @CASE_R;

That's why ?***... works for any number of * but ...***? only works for up to 5 *.

There might be a way to "program" calt/OT substitution to propagate backwards that I'm not aware of and I'd be happy to update Inter to take advantage of such a technique if it exist.

If not, all we can do is to introduce more explicit backtracking rules or add substitution exceptions to suppress certain scenarios of "automatic case matching" behavior