Hi,
On 03/12/2014 10:28 PM, Jason Merrill wrote:
On 03/12/2014 12:12 PM, Paolo Carlini wrote:
- cxx_constant_value (condition);
+ require_potential_rvalue_constant_expression (condition);
We need both, actually; cxx_constant_value catches some cases that the
other doesn't.
Ok, I think I got confused when I compared to cxx_alignas_expr: in the
present case 'condition' is already the result of maybe_constant_value
(thus it seems we would waste work) but, at variance with
cxx_constant_value called by the former, it allows for nonconstants, and
we want to emit at this point also the errors suppressed the first time
cxx_eval_outermost_constant_expr is called... Thanks for your patience,
now the various *_constant_* helpers are more clear ;)
The below also passes testing.
Thanks,
Paolo.
///////////////////
Index: cp/semantics.c
===================================================================
--- cp/semantics.c (revision 208507)
+++ cp/semantics.c (working copy)
@@ -6860,7 +6860,8 @@ finish_static_assert (tree condition, tree message
else if (condition && condition != error_mark_node)
{
error ("non-constant condition for static assertion");
- cxx_constant_value (condition);
+ if (require_potential_rvalue_constant_expression (condition))
+ cxx_constant_value (condition);
}
input_location = saved_loc;
}
Index: testsuite/g++.dg/cpp0x/static_assert10.C
===================================================================
--- testsuite/g++.dg/cpp0x/static_assert10.C (revision 0)
+++ testsuite/g++.dg/cpp0x/static_assert10.C (working copy)
@@ -0,0 +1,8 @@
+// PR c++/60254
+// { dg-do compile { target c++11 } }
+
+template<typename T> bool foo(T)
+{
+ int i;
+ static_assert(foo(i), "Error"); // { dg-error "non-constant condition|not
usable" }
+}
Index: testsuite/g++.dg/cpp0x/static_assert11.C
===================================================================
--- testsuite/g++.dg/cpp0x/static_assert11.C (revision 0)
+++ testsuite/g++.dg/cpp0x/static_assert11.C (working copy)
@@ -0,0 +1,10 @@
+// PR c++/60254
+// { dg-do compile { target c++11 } }
+
+struct A
+{
+ template<typename T> bool foo(T)
+ {
+ static_assert(foo(0), "Error"); // { dg-error "non-constant
condition|constant expression" }
+ }
+};
Index: testsuite/g++.dg/cpp0x/static_assert3.C
===================================================================
--- testsuite/g++.dg/cpp0x/static_assert3.C (revision 208507)
+++ testsuite/g++.dg/cpp0x/static_assert3.C (working copy)
@@ -1,4 +1,4 @@
// { dg-do compile { target c++11 } }
static_assert(7 / 0, "X"); // { dg-error "non-constant condition"
"non-constant" }
// { dg-warning "division by zero" "zero" { target *-*-* } 2 }
-// { dg-error "7 / 0.. is not a constant expression" "not a constant" { target
*-*-* } 2 }
+// { dg-error "division by zero is not a constant-expression" "not a constant"
{ target *-*-* } 2 }
