Further, we are not convinced the effects of this paper are in the
best interests of users. The result of voting in favor of this
proposal is for this code to be diagnosed in C++11 mode:

[[deprecated("this has a reason")]] int foo;
[[nodiscard("this also has a reason")]] int func();

because this proposes, as a DR, to require an implementation to
diagnose the syntactic violation of providing an attribute argument
list when the grammar does not allow one for these attributes in that
language mode.