Error message of the test command

[Bost]

Hi. Suppose there's an erroneous expression (forgotten semicolons):

> test 1 = 2 and echo true or echo false
test: Expected a combining operator like '-a' at index 3

Then it's unclear what is index 3, especially if you're not sure if the indexing starts at 0 or 1 [1]. I'd propose a better message:
test: Expected a combining operator like '-a', found ...

Thanx

[1]: I.e. are parameters of the test treated as a fish-specific list or does it come from C++ or python code?

> fish --version
fish, version 3.0.2
> echo $version 
3.0.2

> uname -a
Linux martin 5.0.0-23-generic #24-Ubuntu SMP Mon Jul 29 15:36:44 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
> echo $TERM 
xterm-256color
> sh -c 'env HOME=$(mktemp -d) fish'
Welcome to fish, the friendly interactive shell

[ridiculousfish]

Yep that would be nice.

[zanchey]

Some discussion previously in #2860.

[faho]

Okay, the errors now look like

   > test 1 = 2 and echo true or echo false
   test: Expected a combining operator like '-a' at index 4
   1 = 2 and echo true or echo false
            ^