re PR c++/66387 (ICE in make_decl_rtl with lambda)

	PR c++/66387
	* semantics.c (process_outer_var_ref): Make sure the value is
	actually constant before returning it.
	* typeck.c (cp_build_array_ref): Allow subscripting non-lvalue
	array.

From-SVN: r224287

gcc/cp/ChangeLog

+2015-06-09  Jason Merrill  <jason@redhat.com>
+
+	PR c++/66387
+	* semantics.c (process_outer_var_ref): Make sure the value is
+	actually constant before returning it.
+	* typeck.c (cp_build_array_ref): Allow subscripting non-lvalue
+	array.
+
 2015-06-09  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/65815

gcc/cp/semantics.c

@@ -3128,7 +3128,11 @@ process_outer_var_ref (tree decl, tsubst_flags_t complain)
 	   form, so wait until instantiation time.  */
 	return decl;
       else if (decl_constant_var_p (decl))
-	return scalar_constant_value (decl);
+	{
+	  tree t = maybe_constant_value (convert_from_reference (decl));
+	  if (TREE_CONSTANT (t))
+	    return t;
+	}
     }
 
   if (parsing_nsdmi ())

gcc/cp/typeck.c

@@ -3141,15 +3141,6 @@ cp_build_array_ref (location_t loc, tree array, tree idx,
 	    return error_mark_node;
 	}
 
-      if (!lvalue_p (array))
-	{
-	  if (complain & tf_error)
-	    pedwarn (loc, OPT_Wpedantic, 
-		     "ISO C++ forbids subscripting non-lvalue array");
-	  else
-	    return error_mark_node;
-	}
-
       /* Note in C++ it is valid to subscript a `register' array, since
 	 it is valid to take the address of something with that
 	 storage specification.  */

gcc/testsuite/g++.dg/cpp0x/lambda/lambda-const5.C

+// PR c++/66387
+// { dg-do compile { target c++11 } }
+
+template <typename T>
+void
+bar (T x)
+{
+  x ();
+}
+
+void
+foo ()
+{
+  constexpr int a[1] = { 1 };
+  bar ([&]{ return a[0]; });
+}