This file is indexed.

/usr/src/gcc-4.7/debian/patches/pr26155.diff is in gcc-4.7-source 4.7.4-3ubuntu12.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
# DP: Fix PR c++/26155, taken from the trunk.

gcc/cp/
2012-06-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/26155
	* name-lookup.c (push_namespace): When error recovery is
	impossible just error out in duplicate_decls.

gcc/testsuite/

2012-06-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/26155
	* g++.dg/parse/namespace-alias-1.C: New.

Index: b/src/gcc/testsuite/g++.dg/parse/namespace-alias-1.C
===================================================================
--- /dev/null
+++ b/src/gcc/testsuite/g++.dg/parse/namespace-alias-1.C
@@ -0,0 +1,7 @@
+// PR c++/26155
+
+namespace N
+{
+  namespace M = N;  // { dg-error "previous declaration" }
+  namespace M {}    // { dg-error "declaration of namespace" }
+}
Index: b/src/gcc/cp/name-lookup.c
===================================================================
--- a/src/gcc/cp/name-lookup.c
+++ b/src/gcc/cp/name-lookup.c
@@ -3545,8 +3545,8 @@ void
 push_namespace (tree name)
 {
   tree d = NULL_TREE;
-  int need_new = 1;
-  int implicit_use = 0;
+  bool need_new = true;
+  bool implicit_use = false;
   bool anon = !name;
 
   bool subtime = timevar_cond_start (TV_NAME_LOOKUP);
@@ -3562,8 +3562,8 @@ push_namespace (tree name)
       d = IDENTIFIER_NAMESPACE_VALUE (name);
       if (d)
 	/* Reopening anonymous namespace.  */
-	need_new = 0;
-      implicit_use = 1;
+	need_new = false;
+      implicit_use = true;
     }
   else
     {
@@ -3571,13 +3571,36 @@ push_namespace (tree name)
       d = IDENTIFIER_NAMESPACE_VALUE (name);
       if (d != NULL_TREE && TREE_CODE (d) == NAMESPACE_DECL)
 	{
-	  need_new = 0;
-	  if (DECL_NAMESPACE_ALIAS (d))
-	    {
-	      error ("namespace alias %qD not allowed here, assuming %qD",
-		     d, DECL_NAMESPACE_ALIAS (d));
-	      d = DECL_NAMESPACE_ALIAS (d);
+	  tree dna = DECL_NAMESPACE_ALIAS (d);
+	  if (dna)
+ 	    {
+	      /* We do some error recovery for, eg, the redeclaration
+		 of M here:
+
+		 namespace N {}
+		 namespace M = N;
+		 namespace M {}
+
+		 However, in nasty cases like:
+
+		 namespace N
+		 {
+		   namespace M = N;
+		   namespace M {}
+		 }
+
+		 we just error out below, in duplicate_decls.  */
+	      if (NAMESPACE_LEVEL (dna)->level_chain
+		  == current_binding_level)
+		{
+		  error ("namespace alias %qD not allowed here, "
+			 "assuming %qD", d, dna);
+		  d = dna;
+		  need_new = false;
+		}
 	    }
+	  else
+	    need_new = false;
 	}
     }