Oh, so this is with the GUI setting "Startup path" set to a directory with m-files in it? I agree, using that setting it does not warn when Octave starts like it would if Octave was run from that directory.

The GUI is probably calling Fchdir under the hood, which is probably why this behaves similar to calling "cd" or "chdir" in the interpreter later and not printing a warning.

Would we really want to change this behavior?

1. chdir(dir) or cd(dir) → no warning

I could cd to a directory just to look at things, and then cd back out, without ever having any intention to execute the flip.m m-file.  I think it might be annoying to get lots of false positive warnings about m-files which are not really problems.

I second Mike's experiments in that the GUI and the CLI both reproduce the same set of warnings under the same set of circumstances.

I also can reproduce the difference between a compiled function and an m-file.  That seems small, so I lowered the priority, but worth fixing if it would be easy to do so.

Whe warning  "function foo.m shadows a core library function"
is missing for some circumstances.

The following statements assumes that there is a function "flip.m" that shadows a core library function.
 

1)
When starting octave with  "octave-cli" It checks the pwd for any function that shadows and reports it at start up.

When starting octave with "octave" (run GUI) there is no warning.

2)
Running octave-cli and then addpath to a folder that has "flip.m" octave then gives a warning.

Running octave-cli and then CD to a folder that has "flip.m" and no warning is given.

3)
Running GUI and CD or addpath there is no warning issued.