Authors: Joseph Myers
Date: 2026-09-01
Submitted against: C2Y (N3886 draft)
Status: Open
In reflector message 29430, Corentin Jabot noted that the adoption of N3418, disallowing producing a UCN by token concatenation, was the opposite of existing practice and that C++ requires this to be accepted, so the change diverges C from C++ without good reason.
In 6.10.5.4 (The ## operator), delete the second Constraint.
A character sequence that matches the syntax of a universal character name shall not be produced by token concatenation.