[C++ PATCH,committed] Fix PR 1787, 4498

[Kriang Lerdsuwanakij <lerdsuwa at users dot sourceforge dot net>]

Hi,

The following patch fixes an ICE when a namespace is used in using
declaration, for example:
        namespace std {}
        using ::std;
This has been reported several times in the GNATS.  The patch adds
NAMESPACE_DECL handling code to validate_nonmember_using_decl.
Tested with no regressions on i686-pc-linux-gnu.
Patch commit by obvious rule.

--Kriang

2001-10-27  Kriang Lerdsuwanakij  <lerdsuwa@users.sourceforge.net>

        * decl2.c (validate_nonmember_using_decl): Handle NAMESPACE_DECL.

diff -cprN gcc-main-save/gcc/cp/decl2.c gcc-main-new/gcc/cp/decl2.c
*** gcc-main-save/gcc/cp/decl2.c        Sat Oct 27 20:14:17 2001
--- gcc-main-new/gcc/cp/decl2.c Sat Oct 27 19:42:13 2001
*************** validate_nonmember_using_decl (decl, sco
*** 4877,4882 ****
--- 4877,4887 ----
        *scope = global_namespace;
        *name = decl;
      }
+   else if (TREE_CODE (decl) == NAMESPACE_DECL)
+     {
+       cp_error ("namespace `%D' not allowed in using-declaration", decl);
+       return NULL_TREE;
+     }
    else
      my_friendly_abort (382);
    if (DECL_P (*name))
diff -cprN gcc-main-save/gcc/testsuite/g++.dg/lookup/using2.C gcc-main-new/gcc/testsuite/g++.dg/lookup/using2.C
*** gcc-main-save/gcc/testsuite/g++.dg/lookup/using2.C  Tue Oct  9 22:44:25 2001
--- gcc-main-new/gcc/testsuite/g++.dg/lookup/using2.C   Sat Oct 27 20:33:14 2001
*************** namespace N
*** 25,30 ****
--- 25,32 ----
    template<int> void f() {}
  }
  
+ using N;             // { dg-error "parse error" "" }
+ using ::N;           // { dg-error "using-declaration" "" }
  using N::f< 0 >;     // { dg-error "using-declaration" "" }
  
  struct  A {