Steps to reproduce

1. gvim.exe --clean t.vim
2. :set gfn=consolas:h20
3. input "if ... elseif ..."

if "foo" ==? "foo"
    echo "first"
elseif "foo" ==? "foo"
    echo "second"
endif

4. :w
5. :so %

Why is 'elseif "foo" ==? "foo"' the invalid expression?

Expected behaviour

No E15 message

Version of Vim

9.0.0861

Environment

Windows 10 64bit

Logs and stack traces

No response