autoload path completion with expansions

[Bart Schaefer <schaefer@brasslantern.com>]

Starting from zsh -f + compinit + zstyle '*' format %d (so, no completer style)

% autoload $PWD/<TAB>
`vars' or `shell function'

This surprised me, because

% ls $PWD/<TAB>
file
(list of files in the current directory)

Turns out this is because _typeset (which handles autoload) only calls
_files when the word on the command line already begins with "/" or
"~".

I debated also adding \` to the pattern.  Thoughts?

diff --git a/Completion/Zsh/Command/_typeset b/Completion/Zsh/Command/_typeset
index d3304bed0..26eab0b21 100644
--- a/Completion/Zsh/Command/_typeset
+++ b/Completion/Zsh/Command/_typeset
@@ -101,9 +101,9 @@ if [[ "$state" = vars_eq ]]; then
     elif (( $+opt_args[-w] )); then
       _wanted files expl 'zwc file' _files -g '*.zwc(-.)' && ret=0
     elif [[ $service = autoload || -n $opt_args[(i)-[uU]] ]]; then
-      if [[ $PREFIX[1] = [/~] ]]; then
+      if [[ $PREFIX[1] = [$/~] ]] && _files; then
        # Autoload by absolute path
-       _files && ret=0
+       ret=0
       else
          args=(${^fpath}/*(-.:t))
          # Filter out functions already loaded or marked for autoload.