decl2.c (do_nonmember_using_decl): Don't complain if we find same function.

cp:
	* decl2.c (do_nonmember_using_decl): Don't complain if we find
	same function. Do complain about ambiguating extern "C"
	declarations.
testsuite:
	* g++.old-deja/g++.other/using9.C: New test.

From-SVN: r40148

4 files changed, 43 insertions, 13 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index fc3fb94..c5d0c95 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2001-03-01  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* decl2.c (do_nonmember_using_decl): Don't complain if we find
+	same function. Do complain about ambiguating extern "C"
+	declarations.
+
 2001-02-28  Nathan Sidwell  <nathan@codesourcery.com>
 
 	Remove floating point and complex type template constant parms.
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index b371611..d115dcc 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -5126,22 +5126,21 @@ do_nonmember_using_decl (scope, name, oldval, oldtype, newval, newtype)
 	    {
 	      tree old_fn = OVL_CURRENT (tmp1);
 
-	      if (!OVL_USED (tmp1)
-		  && compparms (TYPE_ARG_TYPES (TREE_TYPE (new_fn)),
-				TYPE_ARG_TYPES (TREE_TYPE (old_fn))))
+              if (new_fn == old_fn)
+                /* The function already exists in the current namespace.  */
+                break;
+	      else if (OVL_USED (tmp1))
+	        continue; /* this is a using decl */
+	      else if (compparms (TYPE_ARG_TYPES (TREE_TYPE (new_fn)),
+		  		  TYPE_ARG_TYPES (TREE_TYPE (old_fn))))
 		{
-		  if (!(DECL_EXTERN_C_P (new_fn)
-			&& DECL_EXTERN_C_P (old_fn)))
-		    /* There was already a non-using declaration in
-		       this scope with the same parameter types.  */
-		    cp_error ("`%D' is already declared in this scope",
-			      name);
+	          /* There was already a non-using declaration in
+		     this scope with the same parameter types. If both
+	             are the same extern "C" functions, that's ok.  */
+                  if (!decls_match (new_fn, old_fn))
+    	            cp_error ("`%D' is already declared in this scope", name);
 		  break;
 		}
-	      else if (duplicate_decls (new_fn, old_fn))
-		/* We're re-using something we already used 
-		   before.  We don't need to add it again.  */ 
-		break;
 	    }
 
 	  /* If we broke out of the loop, there's no reason to add
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fd0371d..414c253 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2001-03-01  Nathan Sidwell  <nathan@codesourcery.com>
+
+	* g++.old-deja/g++.other/using9.C: New test.
+
 2001-02-28  Ovidiu Predescu  <ovidiu@cup.hp.com>
 
 	* objc/execute/bycopy-3.m: Added new test from Nicola Pero.
diff --git a/gcc/testsuite/g++.old-deja/g++.other/using9.C b/gcc/testsuite/g++.old-deja/g++.other/using9.C
new file mode 100644
index 0000000..acfab50
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.other/using9.C
@@ -0,0 +1,21 @@
+// Build don't link:
+// 
+// Copyright (C) 2000 Free Software Foundation, Inc.
+// Contributed by Nathan Sidwell 26 Feb 2001 <nathan@codesourcery.com>
+
+// Bug 75. using declarations cannot introduce functions which ambiguate
+// those in the current namespace, BUT here we're reaccessing the current
+// namespace -- the function is not being 'introduced'.
+
+extern int a();
+struct x {};
+
+using ::x;
+using ::a;
+
+extern "C" void foo ();
+
+namespace {
+  extern "C" int foo ();
+  using ::foo; // ERROR - already in use
+}