re PR c++/48557 ([C++0x][SFINAE] Hard errors with void as operand of binary built-in operators)

	PR c++/48557
	* typeck.c (cp_build_binary_op): Don't decay void operands.

From-SVN: r172433

gcc/cp/ChangeLog

 2011-04-14  Jason Merrill  <jason@redhat.com>
 
+	PR c++/48557
+	* typeck.c (cp_build_binary_op): Don't decay void operands.
+
 	PR c++/48446
 	* decl.c (compute_array_index_type): Use get_temp_regvar instead
 	of variable_size.

gcc/cp/typeck.c

@@ -3646,16 +3646,16 @@ cp_build_binary_op (location_t location,
       || code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
       || code == TRUTH_XOR_EXPR)
     {
-      if (!really_overloaded_fn (op0))
+      if (!really_overloaded_fn (op0) && !VOID_TYPE_P (TREE_TYPE (op0)))
 	op0 = decay_conversion (op0);
-      if (!really_overloaded_fn (op1))
+      if (!really_overloaded_fn (op1) && !VOID_TYPE_P (TREE_TYPE (op1)))
 	op1 = decay_conversion (op1);
     }
   else
     {
-      if (!really_overloaded_fn (op0))
+      if (!really_overloaded_fn (op0) && !VOID_TYPE_P (TREE_TYPE (op0)))
 	op0 = default_conversion (op0);
-      if (!really_overloaded_fn (op1))
+      if (!really_overloaded_fn (op1) && !VOID_TYPE_P (TREE_TYPE (op1)))
 	op1 = default_conversion (op1);
     }
 

gcc/testsuite/ChangeLog

 2011-04-14  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/sfinae14.C: New.
+
 	* g++.dg/ext/vla10.C: New.
 
 2011-04-14  Richard Guenther  <rguenther@suse.de>

gcc/testsuite/g++.dg/cpp0x/sfinae14.C

+// PR c++/48557
+// { dg-options -std=c++0x }
+
+template<class T>
+struct add_rval_ref
+{
+  typedef T&& type;
+};
+
+template<>
+struct add_rval_ref<void>
+{
+  typedef void type;
+};
+
+template<class T>
+typename add_rval_ref<T>::type create();
+
+template<class T, class U,
+  class = decltype(create<T>() + create<U>())
+>
+char f(int);
+
+template<class, class>
+char (&f(...))[2];
+
+static_assert(sizeof(f<void, int>(0)) != 1, "Error");  // (a)