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[C++ PATCH] Don't allow taking the address of an rvalue reference (PR c++/35153)
- From: "Doug Gregor" <doug dot gregor at gmail dot com>
- To: "GCC Patches" <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 15 Feb 2008 15:48:11 -0500
- Subject: [C++ PATCH] Don't allow taking the address of an rvalue reference (PR c++/35153)
This tiny little patch makes sure that we don't try to take the
address of an rvalue. Before C++0x rvalue references, we had all of
the cases covered; now we can end up with a function call that returns
an rvalue reference. In this case, we'll wrap an INDIRECT_REF around
the call... and not diagnose when we've taken the address of that
rvalue. I think this bug is technically a regression, because we used
to reject the invalid code in the test case but now we accept it. This
patch fixes that problem.
Tested i686-pc-linux-gnu; okay for 4.3?
- Doug
2008-02-15 Douglas Gregor <doug.gregor@gmail.com>
PR c++/35153
* typeck.c (build_x_unary_op): Don't allow us to take the address
of an rvalue that's hiding being an INDIRECT_REF. We can only end
up triggering that error when we have some kind of rvalue
reference.
2008-02-15 Douglas Gregor <doug.gregor@gmail.com>
PR c++/35153
* g++.dg/cpp0x/rref-35153.C: New.
Index: cp/typeck.c
===================================================================
--- cp/typeck.c (revision 132347)
+++ cp/typeck.c (working copy)
@@ -4040,6 +4040,10 @@ build_x_unary_op (enum tree_code code, t
}
else if (TREE_CODE (xarg) == TARGET_EXPR)
warning (0, "taking address of temporary");
+ else if (TREE_CODE (xarg) == INDIRECT_REF
+ && real_lvalue_p (xarg) == clk_none)
+ error ("cannot take the address of rvalue %<%E%>", xarg);
+
exp = build_unary_op (ADDR_EXPR, xarg, 0);
}
Index: testsuite/g++.dg/cpp0x/rref-35153.C
===================================================================
--- testsuite/g++.dg/cpp0x/rref-35153.C (revision 0)
+++ testsuite/g++.dg/cpp0x/rref-35153.C (revision 0)
@@ -0,0 +1,3 @@
+// { dg-options "-std=c++0x" }
+int && f();
+void g() { &(f()); } // { dg-error "address of rvalue" }