The Debian package clc-intercal includes a program named
/usr/bin/oo, ick
(with a space in its name).
If I type:
flare% oo,\
("flare% " is my prompt; there is a space after the backslash above)
and then press TAB, this is completed to
flare% oo, ick
; if I then press ENTER, it says:
zsh: command not found: oo,
On the other hand, if I continue typing to get
flare% oo,\ ick
(without trying completion), and then press ENTER, the program executes
correctly.
This only seems to affect the old-style completion. So though it remains a bug, you can avoid it by using the new system - add these lines to your .zshrc: autoload -U compinit compinit