commenting a *make* directive that is a *shell* command

[Robert P. J. Day]

  ok, i've played with this for the last several minutes and i'm
getting confused but i'm sure it's something simple.  what is the
processing here?

...
all:
        # $(warning whatever)

  that command above has a leading tab so, according to the docs, it
should be treated as a shell command.  but it's clearly the make
warning built-in and, even with that "#", it's processed by make as a
warning.  why?

  if i remove that leading tab, then, of course, it's commented out
and does what i would have expected.  so what's happening above?

rday