On 6/2/23 11:55, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linu-xgnu, does this look OK for trunk?
-- >8 --
Here we notice the 'this' conversion for the call f<void>() is bad, so
we correctly defer instantiating it, but we end up never adding it to
'bad_fns' since missing_conversion_p for it returns false (its only
argument is the already computed 'this' argument). This is not a huge
deal, but it causes us to longer accept the call with -fpermissive.
So if we have a non-strictly viable template candidate that has not been
instantiated, then we need to add it to 'bad_fns' even if it doesn't
have any missing conversions.
I wonder about using ck_deferred_bad in add_template_candidate for this
case rather than changing the test here? OK either way.
PR c++/106760
gcc/cp/ChangeLog:
* call.cc (add_candidates): Relax test for adding a candidate
to 'bad_fns' to accept an uninstantiated template candidate that
has no missing conversions.
gcc/testsuite/ChangeLog:
* g++.dg/ext/conv3.C: New test.
---
gcc/cp/call.cc | 3 ++-
gcc/testsuite/g++.dg/ext/conv3.C | 16 ++++++++++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/ext/conv3.C
diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
index 2736f55f229..dbf42567cc9 100644
--- a/gcc/cp/call.cc
+++ b/gcc/cp/call.cc
@@ -6632,7 +6632,8 @@ add_candidates (tree fns, tree first_arg, const vec<tree,
va_gc> *args,
if (cand->viable == -1
&& shortcut_bad_convs
- && missing_conversion_p (cand))
+ && (TREE_CODE (cand->fn) == TEMPLATE_DECL
+ || missing_conversion_p (cand)))
{
/* This candidate has been tentatively marked non-strictly viable,
and we didn't compute all argument conversions for it (having
diff --git a/gcc/testsuite/g++.dg/ext/conv3.C b/gcc/testsuite/g++.dg/ext/conv3.C
new file mode 100644
index 00000000000..5f4b4d4cc50
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/conv3.C
@@ -0,0 +1,16 @@
+// PR c++/106760
+// { dg-additional-options "-fpermissive" }
+
+struct S {
+ template<class>
+ int f(...);
+
+ int g() const {
+ return f<void>(); // { dg-warning "discards qualifiers" }
+ }
+};
+
+int main() {
+ S s;
+ s.g();
+}
