From 293678445f2f62406fabf6a70c2bdbae4e8346f3 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 21 Jun 2011 15:05:25 -0400
Subject: [PATCH] re PR c++/49418 (G++ discards cv-quals from template
 parameter types)

	PR c++/49418
	* call.c (cxx_type_promotes_to): Don't strip cv-quals.
	* semantics.c (lambda_return_type): Strip them here.

From-SVN: r175271
---
 gcc/cp/ChangeLog                       |  6 ++++++
 gcc/cp/call.c                          |  2 --
 gcc/cp/semantics.c                     |  2 +-
 gcc/testsuite/ChangeLog                |  5 +++++
 gcc/testsuite/g++.dg/template/param3.C | 12 ++++++++++++
 5 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/template/param3.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 97bead8f0af..558e756fe55 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2011-06-21  Jason Merrill  <jason@redhat.com>
+
+	PR c++/49418
+	* call.c (cxx_type_promotes_to): Don't strip cv-quals.
+	* semantics.c (lambda_return_type): Strip them here.
+
 2011-06-21  Andrew MacLeod  <amacleod@redhat.com>
 
 	* semantics.c: Add sync_ or SYNC__ to builtin names.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index caf95b077ce..3ac7a8e3f54 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -2640,8 +2640,6 @@ type_decays_to (tree type)
     return build_pointer_type (TREE_TYPE (type));
   if (TREE_CODE (type) == FUNCTION_TYPE)
     return build_pointer_type (type);
-  if (!MAYBE_CLASS_TYPE_P (type))
-    type = cv_unqualified (type);
   return type;
 }
 
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 1c9d70ab286..594d239f4ea 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -8177,7 +8177,7 @@ lambda_return_type (tree expr)
       SET_TYPE_STRUCTURAL_EQUALITY (type);
     }
   else
-    type = type_decays_to (unlowered_expr_type (expr));
+    type = cv_unqualified (type_decays_to (unlowered_expr_type (expr)));
   return type;
 }
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2f03f2ad508..b2040700cda 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-06-21  Jason Merrill  <jason@redhat.com>
+
+	PR c++/49418
+	* g++.dg/template/param3.C: New.
+
 2011-06-21  Bernd Schmidt  <bernds@codesourcery.com>
 
 	* gcc.c-torture/excute/builtin-bitops-1.c (MAKE_FUNS): Make
diff --git a/gcc/testsuite/g++.dg/template/param3.C b/gcc/testsuite/g++.dg/template/param3.C
new file mode 100644
index 00000000000..0c1e70326fa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/param3.C
@@ -0,0 +1,12 @@
+// PR c++/49418
+
+template <class T>
+void f (const T t)
+{
+  t = 1;			// { dg-error "" }
+}
+
+int main()
+{
+  f(1);
+}