On Tue, 29 Jun 2021, Jason Merrill wrote:
> On 6/29/21 1:57 PM, Patrick Palka wrote:
> > When push_access_scope is passed a TYPE_DECL for a class type (which
> > can happen during e.g. satisfaction), we undesirably push only the
> > enclosing context of the class instead of the class itself. This causes
> > us to mishandle e.g. testcase below due to us not entering the scope of
> > A before checking its constraints.
> >
> > This patch adjusts push_access_scope accordingly, and introduces an
> > RAII wrapper for it. We also make use of this wrapper right away by
> > replacing the only use of push_nested_class_guard with this new wrapper,
> > which means we can remove this old wrapper (whose functionality is
> > basically subsumed by the new wrapper).
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> > trunk?
> >
> > gcc/cp/ChangeLog:
> >
> > * constraint.cc (get_normalized_constraints_from_decl): Use
> > push_access_scope_guard instead of push_nested_class_guard.
> > * cp-tree.h (struct push_nested_class_guard): Replace with ...
> > (struct push_access_scope_guard): ... this.
> > * pt.c (push_access_scope): When the argument corresponds to
> > a class type, push the class instead of its context.
> > (pop_access_scope): Adjust accordingly.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/cpp2a/concepts-access2.C: New test.
> > ---
> > gcc/cp/constraint.cc | 7 +-----
> > gcc/cp/cp-tree.h | 23 +++++++++++--------
> > gcc/cp/pt.c | 9 +++++++-
> > gcc/testsuite/g++.dg/cpp2a/concepts-access2.C | 13 +++++++++++
> > 4 files changed, 35 insertions(+), 17 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-access2.C
> >
> > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > index 6df3ca6ce32..99d3ccc6998 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -926,12 +926,7 @@ get_normalized_constraints_from_decl (tree d, bool diag
> > = false)
> > tree norm = NULL_TREE;
> > if (tree ci = get_constraints (decl))
> > {
> > - push_nested_class_guard pncs (DECL_CONTEXT (d));
> > -
> > - temp_override<tree> ovr (current_function_decl);
> > - if (TREE_CODE (decl) == FUNCTION_DECL)
> > - current_function_decl = decl;
> > -
> > + push_access_scope_guard pas (decl);
> > norm = get_normalized_constraints_from_info (ci, tmpl, diag);
> > }
> > diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> > index 6f713719589..58da7460001 100644
> > --- a/gcc/cp/cp-tree.h
> > +++ b/gcc/cp/cp-tree.h
> > @@ -8463,21 +8463,24 @@ is_constrained_auto (const_tree t)
> > return is_auto (t) && PLACEHOLDER_TYPE_CONSTRAINTS_INFO (t);
> > }
> > -/* RAII class to push/pop class scope T; if T is not a class, do nothing.
> > */
> > +/* RAII class to push/pop the access scope for T. */
> > -struct push_nested_class_guard
> > +struct push_access_scope_guard
> > {
> > - bool push;
> > - push_nested_class_guard (tree t)
> > - : push (t && CLASS_TYPE_P (t))
> > + tree decl;
> > + push_access_scope_guard (tree t)
> > + : decl (t)
> > {
> > - if (push)
> > - push_nested_class (t);
> > + if (VAR_OR_FUNCTION_DECL_P (decl)
> > + || TREE_CODE (decl) == TYPE_DECL)
> > + push_access_scope (decl);
> > + else
> > + decl = NULL_TREE;
> > }
> > - ~push_nested_class_guard ()
> > + ~push_access_scope_guard ()
> > {
> > - if (push)
> > - pop_nested_class ();
> > + if (decl)
> > + pop_access_scope (decl);
> > }
> > };
> > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
> > index f2039e09cd7..bd8b17ca047 100644
> > --- a/gcc/cp/pt.c
> > +++ b/gcc/cp/pt.c
> > @@ -224,7 +224,7 @@ static void instantiate_body (tree pattern, tree args,
> > tree d, bool nested);
> > /* Make the current scope suitable for access checking when we are
> > processing T. T can be FUNCTION_DECL for instantiated function
> > template, VAR_DECL for static member variable, or TYPE_DECL for
> > - alias template (needed by instantiate_decl). */
> > + for a class or alias template (needed by instantiate_decl). */
> > void
> > push_access_scope (tree t)
> > @@ -234,6 +234,10 @@ push_access_scope (tree t)
> > if (DECL_FRIEND_CONTEXT (t))
> > push_nested_class (DECL_FRIEND_CONTEXT (t));
> > + else if (TREE_CODE (t) == TYPE_DECL
> > + && CLASS_TYPE_P (TREE_TYPE (t))
> > + && DECL_ORIGINAL_TYPE (t) == NULL_TREE)
>
> I suspect DECL_IMPLICIT_TYPEDEF_P is a better test for this case.
That works nicely. How does the following look? Bootstrapped and
regtested on x86_64-pc-linux-gnu.
-- >8 --
gcc/cp/ChangeLog:
* constraint.cc (get_normalized_constraints_from_decl): Use
push_access_scope_guard instead of push_nested_class_guard.
* cp-tree.h (struct push_nested_class_guard): Replace with ...
(struct push_access_scope_guard): ... this.
* pt.c (push_access_scope): When the argument corresponds to
a class type, push the class instead of its context.
(pop_access_scope): Adjust accordingly.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-access2.C: New test.
---
gcc/cp/constraint.cc | 7 +-----
gcc/cp/cp-tree.h | 23 +++++++++++--------
gcc/cp/pt.c | 7 +++++-
gcc/testsuite/g++.dg/cpp2a/concepts-access2.C | 13 +++++++++++
4 files changed, 33 insertions(+), 17 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-access2.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 6df3ca6ce32..99d3ccc6998 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -926,12 +926,7 @@ get_normalized_constraints_from_decl (tree d, bool diag =
false)
tree norm = NULL_TREE;
if (tree ci = get_constraints (decl))
{
- push_nested_class_guard pncs (DECL_CONTEXT (d));
-
- temp_override<tree> ovr (current_function_decl);
- if (TREE_CODE (decl) == FUNCTION_DECL)
- current_function_decl = decl;
-
+ push_access_scope_guard pas (decl);
norm = get_normalized_constraints_from_info (ci, tmpl, diag);
}
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 6f713719589..58da7460001 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -8463,21 +8463,24 @@ is_constrained_auto (const_tree t)
return is_auto (t) && PLACEHOLDER_TYPE_CONSTRAINTS_INFO (t);
}
-/* RAII class to push/pop class scope T; if T is not a class, do nothing. */
+/* RAII class to push/pop the access scope for T. */
-struct push_nested_class_guard
+struct push_access_scope_guard
{
- bool push;
- push_nested_class_guard (tree t)
- : push (t && CLASS_TYPE_P (t))
+ tree decl;
+ push_access_scope_guard (tree t)
+ : decl (t)
{
- if (push)
- push_nested_class (t);
+ if (VAR_OR_FUNCTION_DECL_P (decl)
+ || TREE_CODE (decl) == TYPE_DECL)
+ push_access_scope (decl);
+ else
+ decl = NULL_TREE;
}
- ~push_nested_class_guard ()
+ ~push_access_scope_guard ()
{
- if (push)
- pop_nested_class ();
+ if (decl)
+ pop_access_scope (decl);
}
};
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index d2936c106ba..f8f7616bf2a 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -224,7 +224,7 @@ static void instantiate_body (tree pattern, tree args, tree
d, bool nested);
/* Make the current scope suitable for access checking when we are
processing T. T can be FUNCTION_DECL for instantiated function
template, VAR_DECL for static member variable, or TYPE_DECL for
- alias template (needed by instantiate_decl). */
+ for a class or alias template (needed by instantiate_decl). */
void
push_access_scope (tree t)
@@ -234,6 +234,9 @@ push_access_scope (tree t)
if (DECL_FRIEND_CONTEXT (t))
push_nested_class (DECL_FRIEND_CONTEXT (t));
+ else if (DECL_IMPLICIT_TYPEDEF_P (t)
+ && CLASS_TYPE_P (TREE_TYPE (t)))
+ push_nested_class (TREE_TYPE (t));
else if (DECL_CLASS_SCOPE_P (t))
push_nested_class (DECL_CONTEXT (t));
else if (deduction_guide_p (t) && DECL_ARTIFICIAL (t))
@@ -260,6 +263,8 @@ pop_access_scope (tree t)
current_function_decl = saved_access_scope->pop();
if (DECL_FRIEND_CONTEXT (t)
+ || (DECL_IMPLICIT_TYPEDEF_P (t)
+ && CLASS_TYPE_P (TREE_TYPE (t)))
|| DECL_CLASS_SCOPE_P (t)
|| (deduction_guide_p (t) && DECL_ARTIFICIAL (t)))
pop_nested_class ();
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-access2.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-access2.C
new file mode 100644
index 00000000000..8ddcad236e3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-access2.C
@@ -0,0 +1,13 @@
+// { dg-do compile { target concepts } }
+
+template<class T> requires T::value struct A { };
+template<class T> requires T::value struct B { }; // { dg-error "private" }
+
+struct S {
+private:
+ static constexpr bool value = true;
+ template<class T> requires T::value friend struct A;
+};
+
+A<S> x;
+B<S> y; // { dg-error "constraint" }
--
2.32.0.93.g670b81a890
