We consider all TYPE_ARGUMENT_PACKS distinct types, leading to problems
with redeclarations.
This patch fixes things by:
a) marking all such types for structural comparison
b) teaching structural_comptypes how to compare them.
1) It appears that NONTYPE_ARGUMENT_PACKS just work, I think because we
just compare TREE_OPERANDs, which dtrt.
2) I don't think the ARGUMENT_PACK_INCOMPLETE_P and
ARGUMENT_PACK_EXPLICIT_ARGS affect the comparison, (icbw?)
I'll apply to trunk shortly, unless someone indicates I'm confused.
As the PR says, this comes from the modules branch, where I need to
merge global module entities.
nathan
--
Nathan Sidwell
2020-02-25 Nathan Sidwell <nat...@acm.org>
PR c++/93933
* pt.c (template_parm_to_arg): TYPE_ARGUMENT_PACKS are structural.
(coerce_template_parameter_pack, make_argument_pack)
(tsubst_argument_pack, tsubst, type_unification_real)
(unify_pack_expansion): Likewise.
* typeck.c (structural_comptypes): Compare TYPE_ARGUMENT_PACK args.
diff --git c/gcc/cp/pt.c w/gcc/cp/pt.c
index 6c9abb8f3d3..8716f979027 100644
--- c/gcc/cp/pt.c
+++ w/gcc/cp/pt.c
@@ -4670,6 +4670,7 @@ template_parm_to_arg (tree t)
TREE_VEC_ELT (vec, 0) = make_pack_expansion (t);
t = cxx_make_type (TYPE_ARGUMENT_PACK);
+ SET_TYPE_STRUCTURAL_EQUALITY (t);
SET_ARGUMENT_PACK_ARGS (t, vec);
}
}
@@ -8500,7 +8501,10 @@ coerce_template_parameter_pack (tree parms,
if (TREE_CODE (TREE_VALUE (parm)) == TYPE_DECL
|| TREE_CODE (TREE_VALUE (parm)) == TEMPLATE_DECL)
- argument_pack = cxx_make_type (TYPE_ARGUMENT_PACK);
+ {
+ argument_pack = cxx_make_type (TYPE_ARGUMENT_PACK);
+ SET_TYPE_STRUCTURAL_EQUALITY (argument_pack);
+ }
else
{
argument_pack = make_node (NONTYPE_ARGUMENT_PACK);
@@ -13007,7 +13011,10 @@ make_argument_pack (tree vec)
tree pack;
tree elt = TREE_VEC_ELT (vec, 0);
if (TYPE_P (elt))
- pack = cxx_make_type (TYPE_ARGUMENT_PACK);
+ {
+ pack = cxx_make_type (TYPE_ARGUMENT_PACK);
+ SET_TYPE_STRUCTURAL_EQUALITY (pack);
+ }
else
{
pack = make_node (NONTYPE_ARGUMENT_PACK);
@@ -13050,19 +13057,24 @@ tsubst_argument_pack (tree orig_arg, tree args, tsubst_flags_t complain,
tree in_decl)
{
/* Substitute into each of the arguments. */
- tree new_arg = TYPE_P (orig_arg)
- ? cxx_make_type (TREE_CODE (orig_arg))
- : make_node (TREE_CODE (orig_arg));
-
tree pack_args = tsubst_template_args (ARGUMENT_PACK_ARGS (orig_arg),
args, complain, in_decl);
- if (pack_args == error_mark_node)
- new_arg = error_mark_node;
- else
- SET_ARGUMENT_PACK_ARGS (new_arg, pack_args);
+ tree new_arg = error_mark_node;
+ if (pack_args != error_mark_node)
+ {
+ if (TYPE_P (orig_arg))
+ {
+ new_arg = cxx_make_type (TREE_CODE (orig_arg));
+ SET_TYPE_STRUCTURAL_EQUALITY (new_arg);
+ }
+ else
+ {
+ new_arg = make_node (TREE_CODE (orig_arg));
+ TREE_CONSTANT (new_arg) = TREE_CONSTANT (orig_arg);
+ }
- if (TREE_CODE (new_arg) == NONTYPE_ARGUMENT_PACK)
- TREE_CONSTANT (new_arg) = TREE_CONSTANT (orig_arg);
+ SET_ARGUMENT_PACK_ARGS (new_arg, pack_args);
+ }
return new_arg;
}
@@ -15804,8 +15816,11 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
if (code == NONTYPE_ARGUMENT_PACK)
r = make_node (code);
else
- r = cxx_make_type (code);
-
+ {
+ r = cxx_make_type (code);
+ SET_TYPE_STRUCTURAL_EQUALITY (r);
+ }
+
tree pack_args = ARGUMENT_PACK_ARGS (t);
pack_args = tsubst_template_args (pack_args, args, complain, in_decl);
SET_ARGUMENT_PACK_ARGS (r, pack_args);
@@ -21786,7 +21801,10 @@ type_unification_real (tree tparms,
TREE_CONSTANT (arg) = 1;
}
else
- arg = cxx_make_type (TYPE_ARGUMENT_PACK);
+ {
+ arg = cxx_make_type (TYPE_ARGUMENT_PACK);
+ SET_TYPE_STRUCTURAL_EQUALITY (arg);
+ }
SET_ARGUMENT_PACK_ARGS (arg, make_tree_vec (0));
@@ -22618,7 +22636,10 @@ unify_pack_expansion (tree tparms, tree targs, tree packed_parms,
TREE_CONSTANT (result) = 1;
}
else
- result = cxx_make_type (TYPE_ARGUMENT_PACK);
+ {
+ result = cxx_make_type (TYPE_ARGUMENT_PACK);
+ SET_TYPE_STRUCTURAL_EQUALITY (result);
+ }
SET_ARGUMENT_PACK_ARGS (result, new_args);
diff --git c/gcc/cp/typeck.c w/gcc/cp/typeck.c
index c0c98dad980..0954c37444e 100644
--- c/gcc/cp/typeck.c
+++ w/gcc/cp/typeck.c
@@ -1453,6 +1453,11 @@ structural_comptypes (tree t1, tree t2, int strict)
return same_type_p (UNDERLYING_TYPE_TYPE (t1),
UNDERLYING_TYPE_TYPE (t2));
+ case TYPE_ARGUMENT_PACK:
+ if (!cp_tree_equal (ARGUMENT_PACK_ARGS (t1), ARGUMENT_PACK_ARGS (t2)))
+ return false;
+ break;
+
default:
return false;
}
diff --git c/gcc/testsuite/g++.dg/concepts/pr93933.C w/gcc/testsuite/g++.dg/concepts/pr93933.C
new file mode 100644
index 00000000000..b4f2c36374d
--- /dev/null
+++ w/gcc/testsuite/g++.dg/concepts/pr93933.C
@@ -0,0 +1,31 @@
+// { dg-do compile { target c++17 } }
+// { dg-options "-fconcepts" }
+
+// distilled from <concepts>, via header units
+
+template<typename _ArgTypes>
+struct is_invocable;
+
+template<typename... _Args>
+concept invocable = is_invocable<_Args...>::value;
+
+template<typename _Is>
+requires invocable<_Is>
+class BUG;
+
+template<typename _Is>
+requires invocable<_Is>
+class BUG {}; // { dg-bogus "different constraints" }
+
+template<int> struct is_invocable_NT;
+
+template<int... Ints>
+concept invocable_NT = is_invocable_NT<Ints...>::value;
+
+template<int _Is>
+requires invocable_NT<_Is>
+class BUG_NT;
+
+template<int _Is>
+requires invocable_NT<_Is>
+class BUG_NT {};
