[ 2024-02-22; Reflector poll ]

Set priority to 4 after reflector poll in September 2023.

"Not convinced it's worth adding a small amount of future maintenance burden to catch a tiny amount of nonsense-but-not-dangerous code slightly earlier (at the point of call instead of point of use)."

"NAD. We reject bind_front<null_f>() because bind_front(null_f)() compiles but gives UB. Neither bind_front(42)() nor bind_front<42>() compiles."