[gcc r13-2710] c++: modules ICE with typename friend

[Patrick Palka]

https://gcc.gnu.org/g:f4dad09c543eebc4d33cab277d691ed5646bcd65

commit r13-2710-gf4dad09c543eebc4d33cab277d691ed5646bcd65
Author: Patrick Palka <ppalka@redhat.com>
Date:   Sat Sep 17 09:16:53 2022 -0400

    c++: modules ICE with typename friend
    
    A couple of xtreme-header-* modules tests began ICEing in C++23 mode
    ever since r13-2650-g5d84a4418aa962 which introduced into <ranges> a
    dependently scoped friend declaration:
    
      friend /* typename */ _OuterIter::value_type;
    
    This happens because the streaming code assumes a TYPE_P friend must
    be a class type, but here it's a TYPENAME_TYPE, which doesn't have
    a TEMPLATE_INFO or CLASSTYPE_BEFRIENDING_CLASSES.  This patch tries
    to correct this in a minimal way.
    
    gcc/cp/ChangeLog:
    
            * module.cc (friend_from_decl_list): Don't consider
            CLASSTYPE_TEMPLATE_INFO for a TYPENAME_TYPE friend.
            (trees_in::read_class_def): Don't add to
            CLASSTYPE_BEFRIENDING_CLASSES for a TYPENAME_TYPE friend.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/modules/typename-friend_a.C: New test.
            * g++.dg/modules/typename-friend_b.C: New test.

Diff:
---
 gcc/cp/module.cc                                 |  5 +++--
 gcc/testsuite/g++.dg/modules/typename-friend_a.C | 11 +++++++++++
 gcc/testsuite/g++.dg/modules/typename-friend_b.C |  6 ++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index f27f4d091e5..1a1ff5be574 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -4734,7 +4734,8 @@ friend_from_decl_list (tree frnd)
       if (TYPE_P (frnd))
 	{
 	  res = TYPE_NAME (frnd);
-	  if (CLASSTYPE_TEMPLATE_INFO (frnd))
+	  if (CLASS_TYPE_P (frnd)
+	      && CLASSTYPE_TEMPLATE_INFO (frnd))
 	    tmpl = CLASSTYPE_TI_TEMPLATE (frnd);
 	}
       else if (DECL_TEMPLATE_INFO (frnd))
@@ -12121,7 +12122,7 @@ trees_in::read_class_def (tree defn, tree maybe_template)
 	    {
 	      tree f = TREE_VALUE (friend_classes);
 
-	      if (TYPE_P (f))
+	      if (CLASS_TYPE_P (f))
 		{
 		  CLASSTYPE_BEFRIENDING_CLASSES (f)
 		    = tree_cons (NULL_TREE, type,
diff --git a/gcc/testsuite/g++.dg/modules/typename-friend_a.C b/gcc/testsuite/g++.dg/modules/typename-friend_a.C
new file mode 100644
index 00000000000..aa426fe6cf0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/typename-friend_a.C
@@ -0,0 +1,11 @@
+// { dg-additional-options "-fmodules-ts" }
+export module foo;
+// { dg-module-cmi foo }
+
+template<class T>
+struct A {
+  friend typename T::type;
+  friend void f(A) { }
+private:
+  static constexpr int value = 42;
+};
diff --git a/gcc/testsuite/g++.dg/modules/typename-friend_b.C b/gcc/testsuite/g++.dg/modules/typename-friend_b.C
new file mode 100644
index 00000000000..97da9d82e11
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/typename-friend_b.C
@@ -0,0 +1,6 @@
+// { dg-additional-options "-fmodules-ts" }
+module foo;
+
+struct C;
+struct B { using type = C; };
+struct C { static_assert(A<B>::value == 42); };