[C++ PATCH] Fix lookup if class has a field with the same name as class

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The testcase below (actually already the two struct lines) cause a segfault.
The reason is that g++ now allows structures having fields with the same
name if they don't have user defined constructors, but when doing lookup it
does not expect this to happen (if looking up a type name and non-type is
found, it would just scan CLASSTYPE_TAGS).
This patch seems to fix it (passes bootstrap and does not create any
regressions) and should not slow lookup down unless the case where current
g++ would segfault happens, but if it would be fine to set
if (lfi->name == TYPE_IDENTIFIER (type))
  nval = TYPE_NAME (type);
instead of looking up the TYPE_DECL stored in TYPE_FIELDS(type) chain, the
code would be even simpler.
Ok to commit?

2001-02-19  Jakub Jelinek  <jakub@redhat.com>

	* search.c (lookup_field_r): If looking for type and non-TYPE_DECL
	is found, look first if name does not match the structure name.

	* g++.old-deja/g++.other/lookup22.C: New test.

--- gcc/cp/search.c.jj	Mon Feb 19 12:34:01 2001
+++ gcc/cp/search.c	Mon Feb 19 19:50:10 2001
@@ -1382,11 +1382,27 @@ lookup_field_r (binfo, data)
      we ignore all non-types we find.  */
   if (lfi->want_type && TREE_CODE (nval) != TYPE_DECL)
     {
-      nval = purpose_member (lfi->name, CLASSTYPE_TAGS (type));
-      if (nval)
-	nval = TYPE_MAIN_DECL (TREE_VALUE (nval));
-      else 
-	return NULL_TREE;
+      if (lfi->name == TYPE_IDENTIFIER (type))
+	{
+	  /* If the aggregate has no user defined constructors, we allow
+	     it to have fields with the same name as the enclosing type.
+	     If we are looking for that name, find the corresponding
+	     TYPE_DECL.  */
+	  for (nval = TREE_CHAIN (nval); nval; nval = TREE_CHAIN (nval))
+	    if (DECL_NAME (nval) == lfi->name
+		&& TREE_CODE (nval) == TYPE_DECL)
+	      break;
+	}
+      else
+	nval = NULL_TREE;
+      if (!nval)
+	{
+	  nval = purpose_member (lfi->name, CLASSTYPE_TAGS (type));
+	  if (nval)
+	    nval = TYPE_MAIN_DECL (TREE_VALUE (nval));
+	  else 
+	    return NULL_TREE;
+	}
     }
 
   /* You must name a template base class with a template-id.  */
--- gcc/testsuite/g++.old-deja/g++.other/lookup22.C.jj	Mon Feb 19 19:42:51 2001
+++ gcc/testsuite/g++.old-deja/g++.other/lookup22.C	Mon Feb 19 19:54:55 2001
@@ -0,0 +1,13 @@
+// Test for proper handling of type lookup if base class has field with the
+// same name as the containing class.
+// Build don't link:
+
+struct a { int a; };
+struct b : a {};
+
+b x;
+
+void foo ()
+{
+  x.a = 22;
+}

	Jakub