Re: Is this a parser bug?

[Guy Harrison]

Marcel Loose wrote:

> Hi,
> 
> I stumbled upon a GCC compiler diagnostic which, in my opinion, could
> qualify as a bug.
> When I compile the code (tBug.cc) below:
> 
> #include <sys/types.h>  // contains typedef for ulong
> namespace N
> {
>   typedef unsigned long ulong;
> }
> using namespace N;
> int main()
> {
>   N::ulong nu; // OK.
>   ulong u;     // Parse error. Huh?
> }
> 
> I get the following compiler error:
> 
> tBug.cc: In function `int main()':
> tBug.cc:10: `ulong' undeclared (first use this function)
> tBug.cc:10: (Each undeclared identifier is reported only once for each
> function
>    it appears in.)
> tBug.cc:10: parse error before `;' token

Not a bug, no...

N::ulong nu;
::ulong u;

> The real problem is the ambiguity that arises when the ulong in namespace
> N is "brought into" the global namespace, because now there's two of them;
> the other ulong is defined in /usr/include/sys/types.h. So, I would expect
> a more useful diagnostic along the line of "... ulong ambiguous...",
> instead of an "... undeclared..." diagnostic.

...but admittedly it could be better phrased.