On 2/7/20 3:29 PM, Marek Polacek wrote:
When I implemented C++20 parenthesized initialization of aggregates
I introduced this bogus cp_unevaluated_operand check, thus disabling
this feature in unevaluated context. Oop.
Removing the check turned up another bug: I wasn't checking the
return value of digest_init. So when constructible_expr called
build_new_method_call_1 to see if we can construct one type from
another, it got back a bogus INIT_EXPR that looked something like
*(struct T &) 1 = <<< error >>>. But that isn't the error_mark_node,
so constructible_expr thought we had been successful in creating the
ctor call, and it gave the wrong answer. Covered by paren-init17.C.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
OK.
PR c++/92947 - Paren init of aggregates in unevaluated context.
* call.c (build_new_method_call_1): Don't check
cp_unevaluated_operand. Check the return value of digest_init.
* g++.dg/cpp2a/paren-init21.C: New test.
---
gcc/cp/call.c | 3 ++-
gcc/testsuite/g++.dg/cpp2a/paren-init21.C | 14 ++++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/paren-init21.C
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index fde29f8f631..51621b7dd87 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -10179,7 +10179,6 @@ build_new_method_call_1 (tree instance, tree fns,
vec<tree, va_gc> **args,
the two. */
if (DECL_CONSTRUCTOR_P (fn)
&& !(flags & LOOKUP_ONLYCONVERTING)
- && !cp_unevaluated_operand
&& cxx_dialect >= cxx2a
&& CP_AGGREGATE_TYPE_P (basetype)
&& !user_args->is_empty ())
@@ -10194,6 +10193,8 @@ build_new_method_call_1 (tree instance, tree fns,
vec<tree, va_gc> **args,
else
{
ctor = digest_init (basetype, ctor, complain);
+ if (ctor == error_mark_node)
+ return error_mark_node;
ctor = build2 (INIT_EXPR, TREE_TYPE (instance), instance, ctor);
TREE_SIDE_EFFECTS (ctor) = true;
return ctor;
diff --git a/gcc/testsuite/g++.dg/cpp2a/paren-init21.C
b/gcc/testsuite/g++.dg/cpp2a/paren-init21.C
new file mode 100644
index 00000000000..cfd37193f66
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/paren-init21.C
@@ -0,0 +1,14 @@
+// PR c++/92947 - Paren init of aggregates in unevaluated context.
+// { dg-do compile { target c++2a } }
+
+struct A {
+ int a;
+ int b;
+};
+
+int main()
+{
+ static_assert(__is_constructible(A, int, int));
+ decltype(A(1,2)) foo;
+ bool b = noexcept(A(1,2));
+}
base-commit: 572992c8920d5339a3ac28d442c436d6daa0bfae
