With the acceptance of LWG 3133 during the Kona 2019 meeting it would be now possible to simplify the current wording in [time.clock.req] p4 as follows:

A type TC meets the Cpp17TrivialClock requirements if:
(4.1) - [...]
(4.2) - the types TC::rep, TC::duration, and TC::time_point satisfy the Cpp17EqualityComparable (Table23), Cpp17LessThanComparable (Table 24), Cpp17DefaultConstructible (Table 25), Cpp17CopyConstructible (Table 27), Cpp17CopyAssignable (Table 29), and Cpp17Destructible (Table 30) requirements and the requirements of numeric types (25.2). [Note: This means, in particular, that operations on these types will not throw exceptions. —end note]
(4.3) - [...]
(4.4) - [...]
(4.5) - [...]

This is possible, because the revised numeric types requirements ([numeric.requirements] p1) now explicitly call out the Cpp17DefaultConstructible, Cpp17CopyConstructible, Cpp17CopyAssignable, and Cpp17Destructible requirements.

Could we please perform this simplification editorially?