From: Tino Calancha <tino.calancha@gmail.com>
Date: Fri, 21 Apr 2017 21:16:27 +0900 (JST)
Cc: ynyaaa@gmail.com, Tino Calancha <tino.calancha@gmail.com>,
26580@debbugs.gnu.org, Juri Linkov <juri@linkov.net>
C-M-s \T ; matches lower and upper T
C-M-s T ; just matches upper T
I don't see in the manual this effect on an escaped upper letter.
(defcustom search-upper-case 'not-yanks
"If non-nil, upper case chars disable case fold searching.
That is, upper and lower case chars must match exactly.
This applies no matter where the chars come from, but does not
apply to chars in regexps that are prefixed with `\\'.
If this value is `not-yanks', text yanked into the search string
in Isearch mode is always downcased."
:type '(choice (const :tag "off" nil)
(const not-yanks)
(other :tag "on" t)))