This rule that for a friend with a qualified name we try to find a
matching template was already in C++98, but it seems we never implemented
it, and nobody reported it until 2019.
This patch sets DECL_IMPLICIT_INSTANTIATION to signal to
check_explicit_specialization that we want to find a template, like
grokfndecl already did for explicit template args. check_classfn also needs
to call it, as check_classfn is called after the call to
check_explicit_specialization in grokfndecl, whereas the call to
set_decl_namespace comes sooner. This inconsistency is inelegant, but safer
at this point in the release cycle; I'll unify them in stage 1.
Tested x86_64-pc-linux-gnu, applying to trunk.
PR c++/91618
PR c++/96604
gcc/cp/ChangeLog:
* name-lookup.cc (set_decl_namespace): Set
DECL_IMPLICIT_INSTANTIATION if no non-template match.
* pt.cc (check_explicit_specialization): Check it.
* decl2.cc (check_classfn): Call it.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/friend7.C: Remove xfail.
* g++.dg/template/friend72.C: New test.
* g++.dg/template/friend72a.C: New test.
* g++.dg/template/friend73.C: New test.
---
gcc/cp/decl2.cc | 23 ++++++++++++++++++++++-
gcc/cp/name-lookup.cc | 15 +++++++++++++++
gcc/cp/pt.cc | 4 +++-
gcc/testsuite/g++.dg/cpp0x/friend7.C | 2 +-
gcc/testsuite/g++.dg/template/friend72.C | 15 +++++++++++++++
gcc/testsuite/g++.dg/template/friend72a.C | 14 ++++++++++++++
gcc/testsuite/g++.dg/template/friend73.C | 5 +++++
7 files changed, 75 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/friend72.C
create mode 100644 gcc/testsuite/g++.dg/template/friend72a.C
create mode 100644 gcc/testsuite/g++.dg/template/friend73.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index dc2c924c472..c780702572d 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -734,11 +734,15 @@ check_classfn (tree ctype, tree function, tree
template_parms)
tree pushed_scope = push_scope (ctype);
tree matched = NULL_TREE;
tree fns = get_class_binding (ctype, DECL_NAME (function));
-
+ bool saw_template = false;
+
for (ovl_iterator iter (fns); !matched && iter; ++iter)
{
tree fndecl = *iter;
+ if (TREE_CODE (fndecl) == TEMPLATE_DECL)
+ saw_template = true;
+
/* A member template definition only matches a member template
declaration. */
if (is_template != (TREE_CODE (fndecl) == TEMPLATE_DECL))
@@ -788,6 +792,23 @@ check_classfn (tree ctype, tree function, tree
template_parms)
matched = fndecl;
}
+ if (!matched && !is_template && saw_template
+ && !processing_template_decl && DECL_UNIQUE_FRIEND_P (function))
+ {
+ /* "[if no non-template match is found,] each remaining function template
+ is replaced with the specialization chosen by deduction from the
+ friend declaration or discarded if deduction fails."
+
+ So ask check_explicit_specialization to find a matching template. */
+ SET_DECL_IMPLICIT_INSTANTIATION (function);
+ tree spec = check_explicit_specialization (DECL_NAME (function),
+ function, /* tcount */0,
+ /* friend flag */4,
+ /* attrlist */NULL_TREE);
+ if (spec != error_mark_node)
+ matched = spec;
+ }
+
if (!matched)
{
if (!COMPLETE_TYPE_P (ctype))
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index b7fc2781d53..118da0950af 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -5898,6 +5898,7 @@ set_decl_namespace (tree decl, tree scope, bool friendp)
tree found = NULL_TREE;
bool hidden_p = false;
+ bool saw_template = false;
for (lkp_iterator iter (old); iter; ++iter)
{
@@ -5922,6 +5923,20 @@ set_decl_namespace (tree decl, tree scope, bool friendp)
found = ofn;
hidden_p = iter.hidden_p ();
}
+ else if (TREE_CODE (decl) == FUNCTION_DECL
+ && TREE_CODE (ofn) == TEMPLATE_DECL)
+ saw_template = true;
+ }
+
+ if (!found && friendp && saw_template)
+ {
+ /* "[if no non-template match is found,] each remaining function template
+ is replaced with the specialization chosen by deduction from the
+ friend declaration or discarded if deduction fails."
+
+ So tell check_explicit_specialization to look for a match. */
+ SET_DECL_IMPLICIT_INSTANTIATION (decl);
+ return;
}
if (found)
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 63794a40d5d..78519562953 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -2863,7 +2863,9 @@ check_explicit_specialization (tree declarator,
specialization = 1;
SET_DECL_TEMPLATE_SPECIALIZATION (decl);
}
- else if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
+ else if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR
+ || (DECL_LANG_SPECIFIC (decl)
+ && DECL_IMPLICIT_INSTANTIATION (decl)))
{
if (is_friend)
/* This could be something like:
diff --git a/gcc/testsuite/g++.dg/cpp0x/friend7.C
b/gcc/testsuite/g++.dg/cpp0x/friend7.C
index e1d5f449f5c..4d0961c0397 100644
--- a/gcc/testsuite/g++.dg/cpp0x/friend7.C
+++ b/gcc/testsuite/g++.dg/cpp0x/friend7.C
@@ -21,7 +21,7 @@ struct S {
friend class __attribute__((deprecated)) N3;
[[deprecated]] friend void foo<>(int, int); // { dg-warning "attribute
ignored" }
[[deprecated]] friend void ::foo(int, int); // { dg-warning "attribute
ignored" }
- // { dg-bogus "should have" "PR100339" { xfail *-*-* } .-1 }
+ // { dg-bogus "should have" "PR100339" }
};
template<typename T>
diff --git a/gcc/testsuite/g++.dg/template/friend72.C
b/gcc/testsuite/g++.dg/template/friend72.C
new file mode 100644
index 00000000000..b499909076d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend72.C
@@ -0,0 +1,15 @@
+// PR c++/91618
+// { dg-do link }
+
+template <class T> int f(T t)
+{ return t.i; }
+
+class A {
+ friend int ::f(A);
+ int i;
+};
+
+int main()
+{
+ f(A()); // link error, trying to call non-template function
+}
diff --git a/gcc/testsuite/g++.dg/template/friend72a.C
b/gcc/testsuite/g++.dg/template/friend72a.C
new file mode 100644
index 00000000000..ef6834aae2d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend72a.C
@@ -0,0 +1,14 @@
+// PR c++/91618
+
+template <class T> int f(T t, int)
+{ return t.i; }
+
+class A {
+ friend int ::f(A); // { dg-error "" }
+ int i;
+};
+
+int main()
+{
+ f(A()); // { dg-error "no match" }
+}
diff --git a/gcc/testsuite/g++.dg/template/friend73.C
b/gcc/testsuite/g++.dg/template/friend73.C
new file mode 100644
index 00000000000..d009ec7a990
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/friend73.C
@@ -0,0 +1,5 @@
+// PR c++/96604
+
+struct A { template<typename T> operator T(); };
+struct X {};
+struct B { friend A::operator X(); };
base-commit: 405eda0d34b69fb6ee12ba6ed0f69c2c2411d8ee
prerequisite-patch-id: 6ebd0a0d57278b346f0f14058aaf68ac9619a105
prerequisite-patch-id: 42120f687957746cc6c936531d7dd3a196586b6a
--
2.27.0
