expl3: \cs_generate_variant broke with the last update: undefined control sequence \::T [closed]

Question

The last expl3 update broke my "continue" detection for the index. Here is a MWE: (EDIT: I realized it is possible to reduce it even further)

\documentclass{minimal}
\usepackage{expl3,xparse}
\ExplSyntaxOn

\cs_generate_variant:Nn \tl_if_eq:nnTF { xxTF }

\def\ifevenmarkcontd#1{
    \tl_if_eq:xxTF { me } { you }
    {
    }
    {
    }
}

\ExplSyntaxOff

\begin{document}
\ifevenmarkcontd{anything}
\end{document}

When running it the error message is:

! Undefined control sequence.
<argument> \::T
                \::F
l.19

?

If I use \tl_if_eq:nnTF then it compiles. But I need to expand the arguments, and it did work before the last update. How can I fix this now? What is the reason?

Answer 1

In addition to the point tohecz makes, you don't really need the TF here, which is probably why we've not picked this up in testing. I would do simple

\cs_generate_variant:Nn \tl_if_eq:nnTF { xx }

Answer 2

This is basically a bug in LaTeX3 and as such, it should be reported using the way explained by J. C. Salomon in the comments.