bug#30525: Unexpected matches for input data from a patch file

[SF Markus Elfring]

Hello,

I have tried the command “`printf -- '-\tif\n'|grep -E '^-\s+[^i]'`” out
with the version “3.1-1.4”. I get no match which I expect in this use case.

But I wonder why matches are displayed when if lines are passed from
a patch file instead. Should unwanted characters be also excluded by such
a small regular expression here?

Regards,
Markus