Wrong substitution in some UTF-8 words when global-subword-mode is enabled

[ronisbr]

Issue type

• Bug report

Environment

Emacs version: 27.0.91 Operating System: macOS Catalina Evil version: 1.14.0 Evil installation type: MELPA Graphical/Terminal: Graphical Tested in a make emacs session (see CONTRIBUTING.md): Yes

Reproduction steps

• Start Emacs (make emacs)
• M-x global-subword-mode
• Paste the following code:

function test(ŝt, h)
    return ŝt + h
end

• Go the the t before the comma.
• Type: caw to try changing the word ŝt.

Expected behavior

Only the word ŝt should be deleted.

Actual behavior

The rest of the buffer is deleted leaving the following:

function test(s