From: Jason Merrill <jason@redhat.com>
Date: Wed, 13 Apr 2022 18:49:04 +0000 (-0400)
Subject: c++: template conversion op [PR101698]
X-Git-Tag: releases/gcc-9.5.0~27
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=de0b78d1e75e9483b4550abc38b9199c96465dc5;p=thirdparty%2Fgcc.git

c++: template conversion op [PR101698]

Asking for conversion to a dependent type also makes a BASELINK dependent.

	PR c++/101698

gcc/cp/ChangeLog:

	* pt.c (tsubst_baselink): Also check dependent optype.

gcc/testsuite/ChangeLog:

	* g++.dg/template/conv19.C: New test.
---

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index cf3bb05f805b..62ea5c4d8e55 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -15426,7 +15426,8 @@ tsubst_baselink (tree baselink, tree object_type,
 
   tree binfo_type = BINFO_TYPE (BASELINK_BINFO (baselink));
   binfo_type = tsubst (binfo_type, args, complain, in_decl);
-  bool dependent_p = binfo_type != BINFO_TYPE (BASELINK_BINFO (baselink));
+  bool dependent_p = (binfo_type != BINFO_TYPE (BASELINK_BINFO (baselink))
+		      || optype != BASELINK_OPTYPE (baselink));
 
   if (dependent_p)
     {
diff --git a/gcc/testsuite/g++.dg/template/conv19.C b/gcc/testsuite/g++.dg/template/conv19.C
new file mode 100644
index 000000000000..7a3da939c1fb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/conv19.C
@@ -0,0 +1,34 @@
+// PR c++/101698
+// { dg-do compile { target c++11 } }
+
+class Base {
+ public:
+  template <class T>
+  operator const T&() const = delete;
+
+  virtual operator const int&() const {
+    static int res;
+    return res;
+  }
+};
+
+template <class T>
+class Derive : public Base {
+ public:
+  operator const T&() const override {
+    using Y = int;
+    //static_assert(__is_same_as(T,Y), "");
+
+    static int res;
+
+    res = Base::operator const Y&(); // OK
+    res = Base::operator const T&(); // { dg-bogus "deleted" }
+    return res;
+  }
+};
+
+int main() {
+  Derive<int> a;
+  const int& b = a;
+  (void)b;
+}