zsh: `doubled rest argument definition: *::: :->b4` seen in b4

[tamird]

This is a weird one, and it is seen with the zsh completions generated from b4.

The first time I ever type b4 in a shell and hit tab I see:

tamird@Tamirs-MacBook-Pro b4 % b4
trailers  shazam  send  prep  mbox  diff  ty  pr  kr  am  --

however every subsequent attempt to complete a b4 command produces:

tamird@Tamirs-MacBook-Pro b4 % b4
_arguments:comparguments:327: doubled rest argument definition: *::: :->b4
tamird@Tamirs-MacBook-Pro b4 % b4 pr
_arguments:comparguments:327: doubled rest argument definition: *::: :->b4