Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look
OK for trunk/15?
-- >8 --
Here typename A<S>::VertexSet::size_type is first parsed at namespace
scope and so the scope A<S>::VertexSet is treated as a dependent name
and represented as a TYPENAME_TYPE with tag_type as class_type.[1]
Once we realize we're parsing a member declarator we call
maybe_update_decl_type to reprocess the TYPENAME_TYPE relative to the
class template scope, during which make_typename_type succeeds in
resolving the lookup and the member typedef VertexSet (to the
TEMPLATE_TYPE_PARM S). But then the caller tsubst complains that this
result isn't a class type as per the tag_type.
This patch just relaxes tsubst to allow TYPENAME_TYPE getting resolved
to a wildcard type regardless of the tag_type. This does mean we lose
information about the tag_type during a subsequent tsubst, but that's
probably harmless (famous last words).
[1]: The tag_type should probably be scope_type. Changing this seems
to be a matter of changing cp_parser_qualifying_entity to pass
scope_type instead of class_type, but I don't feel confident about that
and it seems risky. I then got confused as to why that function passes
none_type in the !type_p case; to me it should use scope_type
unconditionally, but doing so breaks things. This approach seems safer
to backport.
PR c++/122752
gcc/cp/ChangeLog:
* pt.cc (tsubst) <case TYPENAME_TYPE>: Allow TYPENAME_TYPE
resolving to a wildcard type.
gcc/testsuite/ChangeLog:
* g++.dg/template/dependent-name19.C: New test.
---
gcc/cp/pt.cc | 2 +-
.../g++.dg/template/dependent-name19.C | 22 +++++++++++++++++++
2 files changed, 23 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/template/dependent-name19.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index cd66aeafd86e..79d21c223052 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -17341,7 +17341,7 @@ tsubst (tree t, tree args, tsubst_flags_t complain,
tree in_decl)
f = TREE_TYPE (f);
}
- if (TREE_CODE (f) != TYPENAME_TYPE)
+ if (!WILDCARD_TYPE_P (f))
{
if (TYPENAME_IS_ENUM_P (t) && TREE_CODE (f) != ENUMERAL_TYPE)
{
diff --git a/gcc/testsuite/g++.dg/template/dependent-name19.C
b/gcc/testsuite/g++.dg/template/dependent-name19.C
new file mode 100644
index 000000000000..87fe7c7e5c04
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/dependent-name19.C
@@ -0,0 +1,22 @@
+// PR c++/122752
+
+struct set {
+ typedef unsigned size_type;
+ unsigned size() { return 42; }
+};
+
+template<class S>
+struct A {
+ typedef S VertexSet;
+ typename VertexSet::size_type size();
+ VertexSet vertices_;
+};
+
+template<class S>
+inline typename A<S>::VertexSet::size_type A<S>::size()
+{ return vertices_.size(); }
+
+int main() {
+ A<set> a;
+ a.size();
+}
--
2.52.0.209.ge85ae279b0
