\copy (query) delimiter syntax error

psql's \copy (query) with a delimiter yields a syntax error:

test=> \copy foo to foo.txt delimiter '|'
(works)

test=> \copy (select * from foo) to foo.txt
(works)

test=> \copy (select * from foo) to foo.txt delimiter '|'
ERROR: syntax error at or near "USING"
LINE 1: COPY ( select * from foo ) TO STDOUT USING DELIMITERS '|'

The problem is that \copy sends USING DELIMITERS for backward
compatibility (comment on line 502 of src/bin/psql/copy.c) but that
COPY (query) doesn't support USING DELIMITERS:

CopyStmt: COPY opt_binary qualified_name opt_column_list opt_oids
copy_from copy_file_name copy_delimiter opt_with copy_opt_list
...
| COPY select_with_parens TO copy_file_name opt_with
copy_opt_list

copy_delimiter:
/* USING DELIMITERS kept for backward compatibility. 2002-06-15 */
opt_using DELIMITERS Sconst

What should be fixed -- COPY or \copy? Does psql's \copy still
need backward compatibility to unsupported pre-7.3?

--
Michael Fuhr