Re: proposal to clean up @node Warning Options in invoke.texi

[Chris Pickett <chris dot pickett at mail dot mcgill dot ca>]

Manuel López-Ibáñez wrote:
> On 10 Jan 2007 05:47:19 +0100, Gabriel Dos Reis
> <gdr@integrable-solutions.net> wrote:
> > Chris Pickett <chris.pickett@mail.mcgill.ca> writes:
> > I assume the -Wno-xxx that are set by default would be moved to the
> > "default" section?
>
> No. Warnings that are not active by default are obviously disabled,
> there is no need to mention them. Actually, we should be more specific
> saying that using Wno-* disables a warning no matter what you put on
> the commandline, so, strictly speaking, it is false that warnings that
> are not enabled by default are equivalent to -Wno-*

I agree.  But if Gaby actually meant the -Wxxx that are set by default, 
which currently means -Wno-xxx is listed, then yes, those -Wxxx would be 
listed in the default section.

> > | # A <-- B && C   option A is implied by options B and C together
>
> Do you have an example of this?

-Wunused-parameter <-- -Wextra && -Wunused

> > | # A --> B        option A implies option B
> > | # A ==> B        option A enables option B
>
> What is the difference between "implies" and "enables" ?

Implies: turning on A turns on B.
Enables: turning on A means that turning on B will have an effect.

There is probably a better wording, maybe "enables" instead of my 
"implies", and "is required by" instead of my "enables".

> > | default --> -Wimport -Wdiv-by-zero -Wendif-labels -Wattributes 
> > -Wmultichar
> > |             -Wnormalized=nfc -Wdeprecated-declarations 
> > -Winvalid-offset-of
> > |             -Wint-to-pointer-cast -Wpointer-to-int-cast
> >
> > plus others that are not controlled by named flags.
>
> Should all warnings be controlled by some or other flag?

I think so, but there is doc-only work that can be done first. 
Insisting on each option being either a super-option or a real option 
but never both would fix this.

> > | -Wimplicit <-- -Wall # redundant implication
> >
> > Hmm, I don't understand what you mean here.
>
> Me neither. Also, you missed -Werror-implicit-function-declaration
> which is a weird and useless option. I have to investigate its
> history.

My original graph had:

-Wimplicit-int <-- -Wall
-Wimplicit-function-declaration <-- -Wall
-Werror-implicit-function-declaration
-Wimplicit --> -Wimplicit-int -Wimplicit-function-declaration
-Wimplicit <-- -Wall # redundant implication

The reason I said this last one is redundant is that -Wall is already 
documented as turning on both sub-options of the -Wimplicit 
super-option.  I don't know what to do about it, but my intuition is 
that -Wimplicit should go away altogether.  For now it seems not 
documenting the last line above would be good.

Cheers,
Chris