Error with cleveref + enumerate + tikz-qtree

Question

I get an error in my document in the following circumstance:

1. Using the cleveref package
2. And the tikz-qtree package (for drawing syntax trees)
3. Inside an enumerate environment

Here's a MWE:

\documentclass{article}

%\usepackage{cleveref} %Uncomment for crash

\usepackage{tikz}
\usepackage{tikz-qtree}

\begin{document}

\begin{enumerate}
  \item foo
    \begin{tikzpicture}
        \Tree [.Foo Bar ]
    \end{tikzpicture}
\end{enumerate}


\end{document}

Here's a link to the log that running that file (with cleveref uncommented) generates: log file. The first error is:

! Package tikz Error: A node must have a (possibly empty) label text.

I've verified the following things:

• It is not a catcode problem, i.e. the catcode of . and [ is 12 both with and without loading cleveref
• The problem goes away if the tree is not embedded in an enumerate, i.e. delete the entire document body and replace it with only the \begin{tikzpicture}...\end{tikzpicture}
• The problem goes away if you change the enumerate to itemize

I tried running the example with \traceon from the trace package, but got mired in the half-million(!) lines of output.

Based on the esoteric combination of packages, I'm not sure a ready answer exists, but hopefully there is a TeX guru out there familiar with the guts of these packages who sees something I cannot.

Answer 1

My money is on a name clash of \@result. There's a suspicious

\@call #1#2->\let \@cont =#2\bgroup \@result ={}#1
#1<-\@subtree 
#2<-\@Tree 
{\let}
{begin-group character {}

\@result ->
{the character =}
Missing character: There is no = in font nullfont!
{begin-group character {}
{end-group character }}

in the log. Without having checked right now, I conjecture that TikZ has a token register of that name, while cleveref uses it as a macro.

Answer 2

A solution :

in tikz-qtree.tex you can replace \@result by \qt@result