Please tell us which fish version you are using by executing the following: 3.1.2

Please tell us which operating system and terminal you are using.

Darwin 19.4.0 Darwin Kernel Version 19.4.0: Wed Mar  4 22:28:40 PST 2020; root:xnu-6153.101.6~15/RELEASE_X86_64 x86_64
screen-256color

Please tell us if you tried fish without third-party customizations Yes
and whether it affected the behavior you are reporting: No

Tell us how to reproduce the problem.

Run the following commend

$ true argument; and echo "worked"
true: Expected 0 args, got 1

Under other shells, however, true and false accept and ignore any arguments passed to them.

$ bash -c "true argument"; and echo "worked"
worked
$ sh -c "true argument"l and echo "worked"
worked