[regression] set ignorecase invalidates search pattern

[hebar...@googlemail.com]

The following scenario (Windows 10, vim 9.1.1591):

test.txt
--------------------------------------------------
Söldner.xxx
Söldner.yyy

Soldner.xxx
Soldner.yyy

" Execute:
"   1) /^\(.*\)\.xxx\n\1\.yyy/
"   2) set ic

" vi: hls noic
--------------------------------------------------

After step one lines 1 to 5 are highlighted.
After step two only lines 4 to are highlighted.

[hebar...@googlemail.com]

Seems the problem occured first in 9.1.0645.

[hebar...@googlemail.com]

Correction: Seems the problem occured first between 9.1.0626 and 9.1.0631.

[hebar...@googlemail.com]

Can anybody confirm this issue?

[Christian Brabandt]

On Mi, 06 Aug 2025, 'hebar...@googlemail.com' via vim_dev wrote:

> Can anybody confirm this issue?

I think it is essentially the same as
https://github.com/vim/vim/issues/17470

As mentioned there, I'll have a look, but it may take a while.

Thanks,
Chris