Issue 2573: Undefined behavior when splicing results in a universal-character-name

Title: Undefined behavior when splicing results in a universal-character-name
Status: drwp
Section: 5.2 [lex.phases]
Submitter: US

Created on 2019-10-23.00:00:00 last changed 11 months ago

Messages

msg7107 (view)

Date: 2023-01-15.00:00:00

Additional notes (January, 2023):

Forwarded to SG12 with paper issue 1405, by decision of the CWG and SG12 chairs.

msg6810 (view)

Date: 2023-09-22.05:34:15

[ Resolved by paper P2621R2 (Undefined behavior in the lexer), adopted in June, 2023. ]

(From National Body comments US 024 and US 025 on the C++20 DIS.)

Subclause 5.2 [lex.phases] bullet 1.2 specifies:

Except for splices reverted in a raw string literal, if a splice results in a character sequence that matches the syntax of a universal-character-name, the behavior is undefined.

Undefined behavior during lexing is not acceptable. The behavior ought to be well-defined, ill-formed, or conditionally-supported.

History
Date	User	Action	Args
2023-12-19 10:15:28	admin	set	status: dr -> drwp
2023-09-22 05:34:15	admin	set	status: open -> dr
2023-01-05 08:22:04	admin	set	messages: + msg7107
2019-10-23 00:00:00	admin	create