From a0a2554d7c86c126de85fcbd5bd7e16dbb5a2693 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Thu, 14 Apr 2022 17:35:35 -0400
Subject: [PATCH] c++: using in diagnostics [PR102987]

The decl pretty-printing code wasn't looking at the flags parameter, so we
were printing 'using' in the middle of an expression.

	PR c++/102987

gcc/cp/ChangeLog:

	* error.cc (dump_decl) [USING_DECL]: Respect flags.

gcc/testsuite/ChangeLog:

	* g++.dg/diagnostic/using1.C: Check pretty-printing.
---
 gcc/cp/error.cc                          | 18 +++++++++++-------
 gcc/testsuite/g++.dg/diagnostic/using1.C |  1 +
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc
index 2b07136b5ca..53a9073d99b 100644
--- a/gcc/cp/error.cc
+++ b/gcc/cp/error.cc
@@ -1439,16 +1439,20 @@ dump_decl (cxx_pretty_printer *pp, tree t, int flags)
 
     case USING_DECL:
       {
-	pp_cxx_ws_string (pp, "using");
-	tree scope = USING_DECL_SCOPE (t);
+	if (flags & TFF_DECL_SPECIFIERS)
+	  pp_cxx_ws_string (pp, "using");
 	bool variadic = false;
-	if (PACK_EXPANSION_P (scope))
+	if (!(flags & TFF_UNQUALIFIED_NAME))
 	  {
-	    scope = PACK_EXPANSION_PATTERN (scope);
-	    variadic = true;
+	    tree scope = USING_DECL_SCOPE (t);
+	    if (PACK_EXPANSION_P (scope))
+	      {
+		scope = PACK_EXPANSION_PATTERN (scope);
+		variadic = true;
+	      }
+	    dump_type (pp, scope, flags);
+	    pp_cxx_colon_colon (pp);
 	  }
-	dump_type (pp, scope, flags);
-	pp_cxx_colon_colon (pp);
 	dump_decl (pp, DECL_NAME (t), flags);
 	if (variadic)
 	  pp_cxx_ws_string (pp, "...");
diff --git a/gcc/testsuite/g++.dg/diagnostic/using1.C b/gcc/testsuite/g++.dg/diagnostic/using1.C
index eb4f18d1d8b..4090dd24a60 100644
--- a/gcc/testsuite/g++.dg/diagnostic/using1.C
+++ b/gcc/testsuite/g++.dg/diagnostic/using1.C
@@ -7,6 +7,7 @@ struct a {
 template <typename c> struct d : c {
   using c::e;
   using f = d;
+  // { dg-message "decltype .c::e" "" { target *-*-* } 0 }
   constexpr int g(decltype(e.b())) { return buh; } // { dg-error "buh" }
 };
 struct h {