Re: [PATCH] [gdb/exp] Fix cast handling for indirection

[Pedro Alves <pedro@palves.net>]

On 2024-05-03 16:27, Tom Tromey wrote:

> Here the function actually returns char*, it's just the debug info is
> missing.
> 
> Normally users should have written:
> 
>     print *(char *) a_loc()
> 
> here, at least after the changes a while ago to require a cast of the
> return type here.  Longer ago, debuginfo-less functions did default to
> int return in gdb, but Pedro (I think) changed this a while back.

Yes.

> 
> I was wondering if this patch causes gdb to accept some weird things
> that might have been rejected in the past, by introducing a hidden cast.
> Maybe print (char) *85732 does something surprising now.  I'm not
> entirely sure if that's bad.

I am totally surprised that:

 +# Regression test for PR31693.
 +gdb_test "p (char)*a_loc ()" " = 97 'a'"

this actually works, instead of telling the user:

  "'a_loc' has unknown return type; cast the call to its declared return type"

It seems like a misfeature to me to assume that "char *" is the right type.

Thus, I don't agree with the patch.