Jason Merrill writes:
> On 12/22/2012 11:03 AM, Dodji Seketeli wrote:
>> [1]: The relacement of the VAR_DECL by its initializer is done by
>> decay_conversion by callig decl_constant_value_safe. That replacement
>> doesn't happen if processing_template_decl is not set. That's why it
>> doesn't happen for the class template instantiation at line 9, leading
>> to no error message there.
>
> This is the bug. decay_conversion on an array should take the
> address, not return the initializer.
Right. So would something like this be acceptable then?
gcc/cp/
PR c++/55311
* pt.c (decay_conversion): Do not return the initializer of an array.
gcc/testsuite/
PR c++/55311
* g++.dg/cpp0x/alias-decl-30.C: New test.
---
gcc/cp/typeck.c| 20 +---
gcc/testsuite/g++.dg/cpp0x/alias-decl-30.C | 15 +++
2 files changed, 28 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/alias-decl-30.C
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index ef76dcd..3fa913d 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -1880,19 +1880,25 @@ decay_conversion (tree exp, tsubst_flags_t complain)
return error_mark_node;
}
- /* FIXME remove? at least need to remember that this isn't really a
- constant expression if EXP isn't decl_constant_var_p, like with
- C_MAYBE_CONST_EXPR. */
- exp = decl_constant_value_safe (exp);
- if (error_operand_p (exp))
-return error_mark_node;
+ code = TREE_CODE (type);
+
+ /* For and array decl decay_conversion should not try to return its
+ initializer. */
+ if (code != ARRAY_TYPE)
+{
+ /* FIXME remove? at least need to remember that this isn't really a
+constant expression if EXP isn't decl_constant_var_p, like with
+C_MAYBE_CONST_EXPR. */
+ exp = decl_constant_value_safe (exp);
+ if (error_operand_p (exp))
+ return error_mark_node;
+}
if (NULLPTR_TYPE_P (type) && !TREE_SIDE_EFFECTS (exp))
return nullptr_node;
/* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
Leave such NOP_EXPRs, since RHS is being used in non-lvalue context. */
- code = TREE_CODE (type);
if (code == VOID_TYPE)
{
if (complain & tf_error)
diff --git a/gcc/testsuite/g++.dg/cpp0x/alias-decl-30.C
b/gcc/testsuite/g++.dg/cpp0x/alias-decl-30.C
new file mode 100644
index 000..7ad5e6d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alias-decl-30.C
@@ -0,0 +1,15 @@
+// Origin PR c++/55311
+// { dg-do compile { target c++11 } }
+
+template
+struct A
+{};
+
+struct B {};
+
+extern constexpr char HELLO_WORLD[] = "hello world";
+
+A g; // <-- This works fine
+
+template
+using PartiallySpecialized = A; // <-- This fails
--
Dodji
