Problem:    Passing -1 for bool is not always rejected.
Solution:   Check for error in a better way. (closes #12358)

Problem:    Some functions give two error messages.
Solution:   Do not give a second error message. (closes #12352)

Problem:    reverse() does not work for a String.
Solution:   Implement reverse() for a String. (Yegappan Lakshmanan,
            closes #12179)

Problem:    no functions for converting from/to UTF-16 index.
Solution:   Add UTF-16 flag to existing funtions and add strutf16len() and
            utf16idx(). (Yegappan Lakshmanan, closes #12216)

Problem:    Cursor may move with autocmd in Visual mode.
Solution:   Restore "VIsual_active" before calling check_cursor().
            (closes #11939)

Problem:    Sporadic Test_range() failure.
Solution:   Clear typeahead.  Move to a separate function. (issue #22771)

Problem:    Cannot get the currently showing mouse shape.
Solution:   Add getmouseshape().

Problem:    Using freed memory when executing delfunc at the more prompt.
Solution:   Check function list not changed in another place. (closes #11437)

Problem:    col() and charcol() only work for the current window.
Solution:   Add an optional winid argument. (Yegappan Lakshmanan,
            closes #11466, closes #11461)

Problem:    append() reports failure when not appending anything.
Solution:   Only report failure when appending something. (closes #11498)