Empty curly Unicode escape is not an error

[RazrFalcon]

> ruby -v
ruby 2.6.8p205 (2021-07-07 revision 67951) [universal.arm64e-darwin21]

> ruby -e 'puts "\\u{}"'


> ruby-parse -v
ruby-parse based on parser version 3.1.2.0

> ruby-parse --32 -E -e '"\\u{}"'
(fragment:0):1:2: fatal: invalid Unicode escape
(fragment:0):1: "\u{}"
(fragment:0):1:  ^~~~ 

[iliabylich]

Just like in #855 I can't reproduce your error:

$ ruby -v bin/ruby-parse --32 -E -e '"\\u{}"'
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin19]
"\\u{}"
^~~~~~~ tSTRING "\\u{}"                         expr_end     [0 <= cond] [0 <= cmdarg]
"\\u{}"
       ^ false "$eof"                           expr_end     [0 <= cond] [0 <= cmdarg]
(str "\\u{}")

$ ruby -ve 'p "\\u{}"'
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin19]
"\\u{}"

Please, try at least Ruby 2.7, older versions are not supported.

[iliabylich]

Similar to #855

I'm closing it, but feel free to reopen it if the error appears again for you with maintained Ruby versions (>= 2.7)

[iliabylich]

This is a real bug, too:

$ /bin/cat test.rb
"\u{}"

$ ruby -v test.rb
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin19]
test.rb:1: warning: possibly useless use of a literal in void context

$ bin/ruby-parse --32 test.rb
test.rb:1:2: fatal: invalid Unicode escape
test.rb:1: "\u{}"
test.rb:1:  ^~~~