On 6/25/24 1:00 AM, Andrew Pinski wrote:
The problem here is even though we pass std namespace to lookup_template_class
as the context, it will look at the current scope for the name too.
The fix is to lookup the qualified name first and then use that
for lookup_template_class.
If lookup_template_class is mishandling an explicit context argument,
let's fix that rather than work around it.
This is how std::initializer_list is handled in listify.
Note g++.dg/cpp1z/decomp22.C testcase now fails correctly
with an error, that tuple_size is not in the std namespace.
I copied a fixed up testcase into g++.dg/cpp1z/decomp62.C.
Bootstrapped and tested on x86_64-linux-gnu with no regressions.
PR c++/115605
gcc/cp/ChangeLog:
* decl.cc (get_tuple_size): Call lookup_qualified_name
before calling lookup_template_class.
(get_tuple_element_type): Likewise.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1z/decomp22.C: Expect an error
* g++.dg/cpp1z/decomp61.C: New test.
* g++.dg/cpp1z/decomp62.C: Copied from decomp22.C
and wrap tuple_size/tuple_element inside std namespace.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
---
gcc/cp/decl.cc | 16 +++++---
gcc/testsuite/g++.dg/cpp1z/decomp22.C | 2 +-
gcc/testsuite/g++.dg/cpp1z/decomp61.C | 53 +++++++++++++++++++++++++++
gcc/testsuite/g++.dg/cpp1z/decomp62.C | 23 ++++++++++++
4 files changed, 88 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1z/decomp61.C
create mode 100644 gcc/testsuite/g++.dg/cpp1z/decomp62.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 03deb1493a4..81dde4d51a3 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -9195,10 +9195,13 @@ get_tuple_size (tree type)
{
tree args = make_tree_vec (1);
TREE_VEC_ELT (args, 0) = type;
- tree inst = lookup_template_class (tuple_size_identifier, args,
+ tree std_tuple_size = lookup_qualified_name (std_node,
tuple_size_identifier);
+ if (std_tuple_size == error_mark_node)
+ return NULL_TREE;
+ tree inst = lookup_template_class (std_tuple_size, args,
/*in_decl*/NULL_TREE,
- /*context*/std_node,
- tf_none);
+ /*context*/NULL_TREE,
+ tf_warning_or_error);
inst = complete_type (inst);
if (inst == error_mark_node
|| !COMPLETE_TYPE_P (inst)
@@ -9224,9 +9227,12 @@ get_tuple_element_type (tree type, unsigned i)
tree args = make_tree_vec (2);
TREE_VEC_ELT (args, 0) = build_int_cst (integer_type_node, i);
TREE_VEC_ELT (args, 1) = type;
- tree inst = lookup_template_class (tuple_element_identifier, args,
+ tree std_tuple_elem = lookup_qualified_name (std_node,
tuple_element_identifier);
+ if (std_tuple_elem == error_mark_node)
+ return NULL_TREE;
+ tree inst = lookup_template_class (std_tuple_elem, args,
/*in_decl*/NULL_TREE,
- /*context*/std_node,
+ /*context*/NULL_TREE,
tf_warning_or_error);
return make_typename_type (inst, type_identifier,
none_type, tf_warning_or_error);
diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp22.C
b/gcc/testsuite/g++.dg/cpp1z/decomp22.C
index 9e6b8df486a..4131486e292 100644
--- a/gcc/testsuite/g++.dg/cpp1z/decomp22.C
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp22.C
@@ -17,5 +17,5 @@ int
foo (C<int> t)
{
auto[x0] = t; // { dg-warning "structured bindings only available with"
"" { target c++14_down } }
- return x0;
+ return x0; /* { dg-error "cannot convert" } */
}
diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp61.C
b/gcc/testsuite/g++.dg/cpp1z/decomp61.C
new file mode 100644
index 00000000000..874844b2c61
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp61.C
@@ -0,0 +1,53 @@
+// PR c++/115605
+// { dg-do compile { target c++17 } }
+// { dg-options "" }
+
+using size_t = decltype(sizeof(0));
+
+namespace std
+{
+ template<class T>
+ struct tuple_size;
+ template<size_t, class>
+ struct tuple_element;
+}
+
+struct mytuple
+{
+ int t;
+ template<size_t>
+ int &get()
+ {
+ return t;
+ }
+};
+
+namespace std
+{
+ template<>
+ struct tuple_size<mytuple>
+ {
+ static constexpr int value = 3;
+ };
+ template<size_t I>
+ struct tuple_element<I, mytuple>
+ {
+ using type = int;
+ };
+}
+
+/* The tuple_size/tuple_element lookup should only be from std and not
+ from the current scope so these 2 functions should work. */
+int foo() {
+ int const tuple_size = 5;
+ mytuple array;
+ auto [a, b, c] = array;
+ return c;
+}
+int foo1() {
+ int const tuple_element = 5;
+ mytuple array;
+ auto [a, b, c] = array;
+ return c;
+}
+
diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp62.C
b/gcc/testsuite/g++.dg/cpp1z/decomp62.C
new file mode 100644
index 00000000000..694f3263bd8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp62.C
@@ -0,0 +1,23 @@
+// PR c++/79205
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+template <unsigned long, typename...> struct B;
+template <unsigned long I, typename H> struct B<I, H> { int b; };
+template <typename... E> struct C { B<0, E...> c; C (C &) = default; C (C &&);
};
+namespace std {
+ template <typename> struct tuple_size;
+ template <> struct tuple_size<C<int>> { static constexpr int value = 1; };
+ template <int, typename> struct tuple_element;
+ template <typename H, typename... T>
+ struct tuple_element<0, C<H, T...>> { typedef int type; };
+}
+template <int, typename... E>
+int &&get (C<E...> &&);
+
+int
+foo (C<int> t)
+{
+ auto[x0] = t; // { dg-warning "structured bindings only available with"
"" { target c++14_down } }
+ return x0;
+}
