Tested x86_64-pc-linux-gnu, applying to trunk.
Marek, I'll leave it to you to judge if there is anything else needed for
P2308.
-- 8< --
The new testcase from P2308 crashed trying to expand 'this' without an
object to refer to, because we stripped the TARGET_EXPR in
create_template_parm_object. So let's leave it on for giving an error.
gcc/cp/ChangeLog:
* pt.cc (create_template_parm_object): Pass TARGET_EXPR to
cxx_constant_value.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/nontype-class64.C: New test.
---
gcc/cp/pt.cc | 5 +++--
gcc/testsuite/g++.dg/cpp2a/nontype-class64.C | 23 ++++++++++++++++++++
2 files changed, 26 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class64.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 903a4a1c363..55c23b642bc 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -7308,14 +7308,15 @@ invalid_tparm_referent_p (tree type, tree expr,
tsubst_flags_t complain)
static tree
create_template_parm_object (tree expr, tsubst_flags_t complain)
{
+ tree orig = expr;
if (TREE_CODE (expr) == TARGET_EXPR)
expr = TARGET_EXPR_INITIAL (expr);
if (!TREE_CONSTANT (expr))
{
if ((complain & tf_error)
- && require_rvalue_constant_expression (expr))
- cxx_constant_value (expr);
+ && require_rvalue_constant_expression (orig))
+ cxx_constant_value (orig);
return error_mark_node;
}
if (invalid_tparm_referent_p (TREE_TYPE (expr), expr, complain))
diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class64.C
b/gcc/testsuite/g++.dg/cpp2a/nontype-class64.C
new file mode 100644
index 00000000000..eb6489238f0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class64.C
@@ -0,0 +1,23 @@
+// Testcase from P2308R1
+// { dg-do compile { target c++20 } }
+
+template<auto n> struct B { /* ... */ };
+B<5> b1; // OK, template parameter type is int
+B<'a'> b2; // OK, template parameter type is char
+B<2.5> b3; // OK, template parameter type is double
+B<void(0)> b4; // { dg-error "void" }
+
+template<int i> struct C { /* ... */ };
+C<{ 42 }> c1; // OK
+
+struct J1 {
+ J1 *self=this;
+};
+B<J1{}> j1; // { dg-error "not a constant expression" }
+
+struct J2 {
+ J2 *self=this;
+ constexpr J2() {}
+ constexpr J2(const J2&) {}
+};
+B<J2{}> j2; // { dg-error "" }
base-commit: c5d34912ad576be1ef19be92f7eabde54b9089eb
--
2.43.0
