A prvalue can have void type, and if it doesn't do anything prohibited in a
constant expression, it's vacuously constant.
* constexpr.c (verify_constant): Allow void_node.
2020-01-15 Jason Merrill <jason@redhat.com>
+ PR c++/93257 - consteval void function.
+ * constexpr.c (verify_constant): Allow void_node.
+
PR c++/92871 - bad code with xvalue and GNU ?: extension.
* call.c (prevent_lifetime_extension): New.
(build_conditional_expr_1): Use it.
verify_constant (tree t, bool allow_non_constant, bool *non_constant_p,
bool *overflow_p)
{
- if (!*non_constant_p && !reduced_constant_expression_p (t))
+ if (!*non_constant_p && !reduced_constant_expression_p (t)
+ && t != void_node)
{
if (!allow_non_constant)
error ("%q+E is not a constant expression", t);
--- /dev/null
+// PR c++/93257
+// { dg-do compile { target c++2a } }
+
+template <bool, typename>
+consteval void test() {}
+
+int main() {
+ test<false, int>();
+ return 0;
+}