Hello,

Today I am making my first posts to this group. Please forgive me if I make mistakes. Thank you.

Here is the context:

Header <iterator>:

template<class F, class... Is>
requires (indirectly_readable<Is> && ...) && invocable<F, iter_reference_t<Is>...>
using indirect_result_t = invoke_result_t<F, iter_reference_t<Is>...>;

Header <variant>:

template<class... Types> requires (three_way_comparable<Types> && ...)
constexpr common_comparison_category_t<compare_three_way_result_t<Types>...>
operator<=>(const variant<Types...>&, const variant<Types...>&);

A requires-clause has the following grammar:

requires-clause:
requires constraint-logical-or-expression
constraint-logical-or-expression:
constraint-logical-and-expression
constraint-logical-or-expression || constraint-logical-and-expression
constraint-logical-and-expression:
primary-expression
constraint-logical-and-expression && primary-expression

In <iterator>, "(indirectly_readable<Is> && ...)", I understand "indirectly_readable<Is>" is a primary-expression, but "..." is not.
In <variant>, "(three_way_comparable<Types> && ...)", I understand "three_way_comparable<Types>" is a primary-expression, but "..." is not.

Am I misunderstanding something, or is this an error?

Thank you,

Robert Schwartz