Re: rfc: __builtin_types_compatible_p and unsigned literals

[Aldy Hernandez <aldyh@redhat.com>]

On Mon, May 06, 2002 at 10:42:08AM +0100, Joseph S. Myers wrote:
> On Mon, 6 May 2002, Aldy Hernandez wrote:
> 
> > for example,
> > 
> > 	int foo (unsigned int blah) { }
> > 
> > accepts foo(31) as well as foo(31U).
> 
> It also accepts foo(31LL) and other such implicitly convertible types, if
> the prototype is in scope.  Or are you referring to the special case where
> a prototype isn't in scope (and for variable arguments), and
> signed/unsigned can be mixed provided the value is representable in both
> types?

i'm not sure i follow you.

what i'm referring to, is that i believe the following should all
return true:

	__builtin_types_compatible_p(int, typeof(1))
	__builtin_types_compatible_p(int, typeof(1L))
	__builtin_types_compatible_p(int, typeof(1LL))
	__builtin_types_compatible_p(int, typeof(1U))
	__builtin_types_compatible_p(int, typeof(1ULL))
	__builtin_types_compatible_p(int, typeof(1UL))
	etc

whereas now, these  return false.  they should return true-- after all,
they are *compatible*.

> > can i "fix" __builtin_types_compatible_p?
> 
> The types aren't compatible.  (Pointers to them aren't even implictly
> convertible, though you'll need -pedantic to get a warning about that.)  

perhaps we should return true, like i suggest, but warn with -pedantic??

aldy