[C++ PATCH] Friend decls

[Nathan Sidwell <nathan@acm.org>]

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With pushdecl revamped, there's no need for do_friend to do some 
checking with a local class friend.  And therefore no need for the very 
specialized lookup_name_innermost_nonclass_level.

push_local_binding will get some more cleanup soon.

Committed to trunk.

nathan
-- 
Nathan Sidwell

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2017-05-24  Nathan Sidwell  <nathan@acm.org>

	cp/
	* friend.c (do_friend): Remove check for existing decl.
	* name-lookup.h (lookup_name_innermost_nonclass_level): Delete.
	* name-lookup.c (push_local_binding): Directly look for binding.
	(lookup_name_innermost_nonclass_level_1): Delete.
	(lookup_name_innermost_nonclass_level): Delete.

	testsuite/
	* g++.dg/lookup/friend12.C: Adjust diagnostics.
	* g++.dg/lookup/friend19.C: New.
	* g++.dg/lookup/friend20.C: New.

Index: cp/friend.c
===================================================================
--- cp/friend.c	(revision 248432)
+++ cp/friend.c	(working copy)
@@ -608,25 +608,8 @@ do_friend (tree ctype, tree declarator,
 	       is instantiated.  */
 	    decl = push_template_decl_real (decl, /*is_friend=*/true);
 	  else if (current_function_decl)
-	    {
-	      /* This must be a local class.  11.5p11:
-
-		 If a friend declaration appears in a local class (9.8) and
-		 the name specified is an unqualified name, a prior
-		 declaration is looked up without considering scopes that
-		 are outside the innermost enclosing non-class scope. For a
-		 friend function declaration, if there is no prior
-		 declaration, the program is ill-formed.  */
-	      tree t = lookup_name_innermost_nonclass_level (DECL_NAME (decl));
-	      if (t)
-		decl = pushdecl (decl, /*is_friend=*/true);
-	      else
-		{
-		  error ("friend declaration %qD in local class without "
-			 "prior declaration", decl);
-		  return error_mark_node;
-		}
-	    }
+	    /* pushdecl will check there's a local decl already.  */
+	    decl = pushdecl (decl, /*is_friend=*/true);
 	  else
 	    {
 	      /* We can't use pushdecl, as we might be in a template
Index: cp/name-lookup.c
===================================================================
--- cp/name-lookup.c	(revision 248432)
+++ cp/name-lookup.c	(working copy)
@@ -2103,7 +2103,13 @@ push_local_binding (tree id, tree decl,
      push_local_binding with a friend decl of a local class.  */
   b = innermost_nonclass_level ();
 
-  if (lookup_name_innermost_nonclass_level (id))
+  cxx_binding *binding = NULL;
+  if (b->kind == sk_namespace)
+    binding = find_namespace_binding (current_namespace, id);
+  else
+    binding = find_local_binding (b, id);
+
+  if (binding)
     {
       /* Supplement the existing binding.  */
       if (!supplement_binding (IDENTIFIER_BINDING (id), decl))
@@ -5430,37 +5436,6 @@ lookup_type_scope (tree name, tag_scope
   return ret;
 }
 
-
-/* Similar to `lookup_name' but look only in the innermost non-class
-   binding level.  */
-
-static tree
-lookup_name_innermost_nonclass_level_1 (tree name)
-{
-  cp_binding_level *b = innermost_nonclass_level ();
-  cxx_binding *binding = NULL;
-
-  if (b->kind == sk_namespace)
-    binding = find_namespace_binding (current_namespace, name);
-  else
-    binding = find_local_binding (b, name);
-
-  return binding ? binding->value : NULL_TREE;
-}
-
-/* Wrapper for lookup_name_innermost_nonclass_level_1.  */
-
-tree
-lookup_name_innermost_nonclass_level (tree name)
-{
-  tree ret;
-  bool subtime = timevar_cond_start (TV_NAME_LOOKUP);
-  ret = lookup_name_innermost_nonclass_level_1 (name);
-  timevar_cond_stop (TV_NAME_LOOKUP, subtime);
-  return ret;
-}
-
-
 /* Returns true iff DECL is a block-scope extern declaration of a function
    or variable.  */
 
Index: cp/name-lookup.h
===================================================================
--- cp/name-lookup.h	(revision 248432)
+++ cp/name-lookup.h	(working copy)
@@ -310,7 +310,6 @@ extern tree get_namespace_binding (tree
 extern void set_global_binding (tree id, tree val);
 extern tree lookup_qualified_name (tree, tree, int, bool, /*hidden*/bool = false);
 extern tree lookup_name_nonclass (tree);
-extern tree lookup_name_innermost_nonclass_level (tree);
 extern bool is_local_extern (tree);
 extern tree lookup_function_nonclass (tree, vec<tree, va_gc> *, bool);
 extern bool pushdecl_class_level (tree);
Index: testsuite/g++.dg/lookup/friend12.C
===================================================================
--- testsuite/g++.dg/lookup/friend12.C	(revision 248422)
+++ testsuite/g++.dg/lookup/friend12.C	(working copy)
@@ -2,9 +2,9 @@
 
 void foo()
 {
+  extern void bar (int); // not the bar we are looking for
   struct A
   {
-    friend void bar();		// { dg-error "without prior declaration" }
+    friend void bar();	// { dg-error "without prior local declaration" }
   };
-  bar();			// { dg-error "3:'bar' was not declared" }
 }
Index: testsuite/g++.dg/lookup/friend19.C
===================================================================
--- testsuite/g++.dg/lookup/friend19.C	(revision 0)
+++ testsuite/g++.dg/lookup/friend19.C	(working copy)
@@ -0,0 +1,29 @@
+// Make sure unhiding friends doesn't unhide similarly named friends
+
+struct X
+{
+  friend int foo (X);
+};
+
+struct Y
+{
+  friend int foo (Y);
+};
+
+void Baz ()
+{
+  foo (X());
+  foo (Y());
+}
+
+int foo (Y);
+int foo (int);
+// foo(X) still hidden
+
+void Bar ()
+{
+  foo (X());
+  foo (Y());
+  ::foo (X()); // { dg-error "" }
+  ::foo (Y());
+}
Index: testsuite/g++.dg/lookup/friend20.C
===================================================================
--- testsuite/g++.dg/lookup/friend20.C	(revision 0)
+++ testsuite/g++.dg/lookup/friend20.C	(working copy)
@@ -0,0 +1,16 @@
+// PR c++/80830
+
+template <int> class a;
+class b
+{
+  friend int operator>> (int, b);
+};
+template <int c> int &operator>> (int &, a<c> &);
+template <int = 3> class a
+{
+  friend int &operator>><> (int &, a &);
+  a<>
+  d ()
+  {
+  }
+};
Index: testsuite/g++.old-deja/g++.jason/scoping12.C
===================================================================
--- testsuite/g++.old-deja/g++.jason/scoping12.C	(revision 248422)
+++ testsuite/g++.old-deja/g++.jason/scoping12.C	(working copy)
@@ -2,9 +2,9 @@
 void f ()
 {
   struct A {
-    friend void g ();		// { dg-error "without prior declaration" }
+    friend void g ();	// { dg-error "without prior local declaration" }
   };
 }
 void h () {
-  g ();				// { dg-error "3:'g' was not declared" } no g in scope
+  g ();			// { dg-error "3:'g' was not declared" } no g in scope
 }