[Bug c++/52949] New: decltype too sensitive to order of declarations?

[Bug c++/52949] New: decltype too sensitive to order of declarations?

[akim.demaille at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52949

             Bug #: 52949
           Summary: decltype too sensitive to order of declarations?
    Classification: Unclassified
           Product: gcc
           Version: 4.7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: akim.demaille@gmail.com


Created attachment 27141
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27141
Test case

I am not sure of myself on this one.  I have read a preversion of the standard
(and I checked n2343 too), and I did not find anything very clear about this. 
I do understand that the "rich" version might require some dependency
resolution in full generality, but then again, I have not found the restriction
spelled out in the standard.  The only restriction I spotted is the case of
overloaded functions.  I apologize if this is the expected behavior.

In the following example, the first use of decltype fails because it does not
see the member_ definition, which is right after it.  The second decltype
passes.


$ g++-mp-4.7 --version
g++-mp-4.7 (GCC) 4.7.0
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++-mp-4.7 -std=c++11 foo.cc
foo.cc:3:27: error: 'member_' was not declared in this scope
foo.cc:3:27: error: 'member_' was not declared in this scope
foo.cc: In function 'int main()':
foo.cc:12:5: error: 'struct Vector' has no member named 'val1'

$ g++-mp-4.8 --version
g++-mp-4.8 (GCC) 4.8.0 20120408 (experimental)
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ g++-mp-4.8 -std=c++11 foo.cc
foo.cc:3:27: error: 'member_' was not declared in this scope
foo.cc:3:27: error: 'member_' was not declared in this scope
foo.cc: In function 'int main()':
foo.cc:12:5: error: 'struct Vector' has no member named 'val1'

[Bug c++/52949] decltype too sensitive to order of declarations?

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52949

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-04-12 15:59:51 UTC ---
The name member_ isn't in scope until it's declared, this is nothing to do with
decltype.

[Bug c++/52949] decltype too sensitive to order of declarations?

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52949

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-04-12 16:12:15 UTC ---
this is no different to;

struct Vector
{
  static const int i = sizeof(member_);   // error
  int member_;
  static const int j = sizeof(member_);   // ok
};