re PR c++/48089 ([C++0x] ICE on in(?)valid in constexpr constructors)

	PR c++/48089
	* semantics.c (potential_constant_expression_1): Don't allow *this
	in a constructor.
	(register_constexpr_fundef): Use potential_rvalue_constant_expression.

From-SVN: r171086

gcc/cp/ChangeLog

 2011-03-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/48089
+	* semantics.c (potential_constant_expression_1): Don't allow *this
+	in a constructor.
+	(register_constexpr_fundef): Use potential_rvalue_constant_expression.
+
 	PR c++/47301
 	* decl.c (compute_array_index_type): Don't bother trying to deal
 	with literal classes in ABI v1.

gcc/cp/semantics.c

@@ -5674,11 +5674,11 @@ register_constexpr_fundef (tree fun, tree body)
       body = unshare_expr (TREE_OPERAND (body, 0));
     }
 
-  if (!potential_constant_expression (body))
+  if (!potential_rvalue_constant_expression (body))
     {
       DECL_DECLARED_CONSTEXPR_P (fun) = false;
       if (!DECL_TEMPLATE_INSTANTIATION (fun))
-	require_potential_constant_expression (body);
+	require_potential_rvalue_constant_expression (body);
       return NULL;
     }
   fundef->body = body;
@@ -7496,7 +7496,16 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
         tree x = TREE_OPERAND (t, 0);
         STRIP_NOPS (x);
         if (is_this_parameter (x))
-	  return true;
+	  {
+	    if (DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)) && want_rval)
+	      {
+		if (flags & tf_error)
+		  error ("the value of the object being constructed is "
+			 "not a constant expression");
+		return false;
+	      }
+	    return true;
+	  }
 	return potential_constant_expression_1 (x, rval, flags);
       }
 

gcc/testsuite/ChangeLog

 2011-03-16  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/constexpr-48089.C: New.
+
 	* g++.dg/cpp0x/constexpr-abi1.C: New.
 
 	* g++.dg/cpp0x/constexpr-46336.C: New.

gcc/testsuite/g++.dg/cpp0x/constexpr-48089.C

+// PR c++/48089
+// { dg-options -std=c++0x }
+
+struct s {
+    constexpr s() : v(v) { }	// { dg-error "object being constructed" }
+    char v;
+};
+
+s bang;