[C++ PATCH] Fix anonymous aggregates (take 2)

[Jakub Jelinek <jakub at redhat dot com>]

On Fri, Feb 02, 2001 at 05:57:57PM +0000, Jason Merrill wrote:
> This should use context_for_name_lookup.

How about this?
While looking at context_for_name_lookup, I found that either
if (!context) context = global_namespace is redundant or the while loop does
not check for context == NULL_TREE properly, because CP_DECL_CONTEXT
guarantees context to be non-NULL and the loop exits only if context is
dereferenced to find out it is either not TYPE_P or it is not
ANON_AGGR_TYPE_P.
As 
static union { union { int a; }; }; at global namespace has second types'
TYPE_CONTEXT NULL_TREE, I think my change is correct although I haven't
found any testcase which would segfault on it.
Ok to commit?

2001-02-02  Jakub Jelinek  <jakub@redhat.com>

	* decl.c (push_class_binding): Use context_for_name_lookup instead
	of CP_DECL_CONTEXT.
	* search.c (context_for_name_lookup): Remove static.  Check for NULL
	context in the loop.
	* cp-tree.h (context_for_name_lookup): Add prototype.

	* g++.old-deja/g++.other/anon6.C: New test.
	* g++.old-deja/g++.other/anon7.C: New test.

--- gcc/cp/decl.c.jj	Sun Jan 28 12:36:36 2001
+++ gcc/cp/decl.c	Fri Feb  2 20:23:04 2001
@@ -1124,7 +1124,7 @@ push_class_binding (id, decl)
 	  else
 	    {
 	      my_friendly_assert (DECL_P (decl), 0);
-	      context = CP_DECL_CONTEXT (decl);
+	      context = context_for_name_lookup (decl);
 	    }
 
 	  if (is_properly_derived_from (current_class_type, context))
--- gcc/cp/search.c.jj	Mon Jan 22 13:58:58 2001
+++ gcc/cp/search.c	Fri Feb  2 20:58:59 2001
@@ -120,7 +120,6 @@ static tree bfs_walk
 	       void *));
 static tree lookup_field_queue_p PARAMS ((tree, void *));
 static tree lookup_field_r PARAMS ((tree, void *));
-static tree context_for_name_lookup PARAMS ((tree));
 static tree canonical_binfo PARAMS ((tree));
 static tree shared_marked_p PARAMS ((tree, void *));
 static tree shared_unmarked_p PARAMS ((tree, void *));
@@ -714,7 +713,7 @@ at_function_scope_p ()
 
 /* Return the scope of DECL, as appropriate when doing name-lookup.  */
 
-static tree
+tree
 context_for_name_lookup (decl)
      tree decl;
 {
@@ -724,9 +723,9 @@ context_for_name_lookup (decl)
      definition, the members of the anonymous union are considered to
      have been defined in the scope in which the anonymous union is
      declared.  */ 
-  tree context = CP_DECL_CONTEXT (decl);
+  tree context = DECL_CONTEXT (decl);
 
-  while (TYPE_P (context) && ANON_AGGR_TYPE_P (context))
+  while (context && TYPE_P (context) && ANON_AGGR_TYPE_P (context))
     context = TYPE_CONTEXT (context);
   if (!context)
     context = global_namespace;
--- gcc/cp/cp-tree.h.jj	Thu Feb  1 13:52:47 2001
+++ gcc/cp/cp-tree.h	Fri Feb  2 20:22:01 2001
@@ -4211,6 +4211,7 @@ extern void init_search_processing		PARA
 extern void reinit_search_statistics		PARAMS ((void));
 extern tree current_scope			PARAMS ((void));
 extern int at_function_scope_p                  PARAMS ((void));
+extern tree context_for_name_lookup		PARAMS ((tree));
 extern tree lookup_conversions			PARAMS ((tree));
 extern tree binfo_for_vtable			PARAMS ((tree));
 extern tree binfo_from_vbase			PARAMS ((tree));
--- gcc/testsuite/g++.old-deja/g++.other/anon6.C.jj	Tue Jan 30 17:05:08 2001
+++ gcc/testsuite/g++.old-deja/g++.other/anon6.C	Tue Jan 30 18:21:59 2001
@@ -0,0 +1,36 @@
+extern "C" void abort ();
+
+struct A {
+  union {
+    int a;
+    double b;
+    int d;
+  };
+  int c;
+};
+
+struct B : public A {
+  union {
+    double a;
+    void *c;
+  };
+  float b;
+  int e;
+};
+
+int main ()
+{
+  struct B b;
+
+  b.a = 1.5;
+  b.b = 2.5;
+  b.d = 1;
+  b.e = 2;
+  if (b.a != 1.5 || b.b != 2.5 || b.d != 1 || b.e != 2)
+    abort ();
+  b.c = &b.a;
+  b.d = b.e;
+  if (b.c != &b.a || b.d != 2)
+    abort ();
+  return 0;
+}
--- gcc/testsuite/g++.old-deja/g++.other/anon7.C.jj	Tue Jan 30 17:16:56 2001
+++ gcc/testsuite/g++.old-deja/g++.other/anon7.C	Tue Jan 30 17:22:52 2001
@@ -0,0 +1,24 @@
+// Build don't link:
+
+struct A {
+  union {
+    int a;	// ERROR - conflicts with previous declaration
+  };
+  int a;	// ERROR - 
+};
+
+struct B {
+  int b;	// ERROR - conflicts with previous declaration
+  union {
+    int b;	// ERROR - duplicate member
+  };		// ERROR - declaration of
+};
+
+struct C {
+  union {
+    int c;	// ERROR - conflicts with previous declaration
+  };
+  union {
+    int c;	// ERROR - duplicate member
+  };		// ERROR - declaration of
+};

	Jakub