confusing "invalid use of end" message in octave-4.2.2

[Sergei Steshenko]

Hello All,

here is a simple example of interactive session demonstrating the probblem:

"

octave:1> foo(end)
error: invalid use of end
octave:1> version
ans = 4.2.2
octave:2>
".


The truth is that 'foo' is undefined, but instead of stating this 
clearly first Octave just prints "error: invalid use of end".


In real life I've stumbled upon this using 'plot' commands with some 
undefined variables, and it was difficult to find out which exactly 
variable was undefined.

--Sergei.