Here ever since r12-6022-gbb2a7f80a98de3 we stopped deeming the partial
specialization #2 to be more specialized than #1 ultimately because
dependent operator expressions now have a DEPENDENT_OPERATOR_TYPE type
instead of an empty type, and this made unify stop deducing T(2) == 1
for K during partial ordering for #1 and #2.
This minimal patch fixes this by making the relevant code in unify
treat DEPENDENT_OPERATOR_TYPE like an empty type.
Bootstrapped and regtested on x86_64-pc-linux-gnu, and preapproved for
trunk by Jason off-list. Does this also look OK for the 12 branch?
PR c++/105425
gcc/cp/ChangeLog:
* pt.cc (unify) <case TEMPLATE_PARM_INDEX>: Treat
DEPENDENT_OPERATOR_TYPE like an empty type.
gcc/testsuite/ChangeLog:
* g++.dg/template/partial-specialization13.C: New test.
---
gcc/cp/pt.cc | 3 ++-
.../g++.dg/template/partial-specialization13.C | 10 ++++++++++
2 files changed, 12 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/template/partial-specialization13.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 3cf1d7af8d2..cf24d482488 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -24276,7 +24276,8 @@ unify (tree tparms, tree targs, tree parm, tree arg,
int strict,
}
}
- if (!TREE_TYPE (arg))
+ if (!TREE_TYPE (arg)
+ || TREE_CODE (TREE_TYPE (arg)) == DEPENDENT_OPERATOR_TYPE)
/* Template-parameter dependent expression. Just accept it for now.
It will later be processed in convert_template_argument. */
;
diff --git a/gcc/testsuite/g++.dg/template/partial-specialization13.C
b/gcc/testsuite/g++.dg/template/partial-specialization13.C
new file mode 100644
index 00000000000..e0a115cd06c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/partial-specialization13.C
@@ -0,0 +1,10 @@
+// PR c++/105425
+// { dg-do compile { target c++11 } }
+
+template<bool> struct when;
+template<class, class> struct A;
+template<class T, bool K> struct A<T, when<K>>; // #1
+template<class T> struct A<T, when<T(2) == 1>> {}; // #2
+A<int, when<true>> a1; // { dg-error "incomplete" }
+A<int, when<false>> a2;
+A<bool, when<true>> a3;
--
2.36.0.rc2.10.g1ac7422e39
