Arguments passed by name

Decided

D-0072, settled by the language’s author: part of spec §18. Older text cites it as 18.72.

name = value, for the parameters after a variadic one and for nothing else, after the positional arguments, in any order; one with a default may be left out whatever else is given, one without must be passed. Chosen by the user for String::format("…", x, allocator = Allocators::Temp): a variadic parameter takes every positional argument after the fixed ones, so an allocator or a #location after it was unreachable, and putting the allocator first would make every call name it. Naming is not extended to ordinary parameters, which keeps one way to pass each argument; it can be widened later without breaking a program. Revises 18.56’s “last”